Category Archives: field crops

agriculture

Protect Pollinators and Natural Enemies of Pests, Choose Pesticides Carefully

A bumble bee and a smaller bee resting on a magenta cosmos covered with tiny water droplets
These bees are just two of the beneficial insects you’ll want to protect from pesticides.

Hopefully we can all agree that protecting friendly insects (pollinators and natural enemies of pests) on our farms and in our gardens and landscapes is important. We want to manage pests, without hurting bees, butterflies, ladybugs, parasitoid wasps, minute pirate bugs, hover flies, ground beetles, and so many more of our insect friends. Using IPM tools other than pesticides is a great way to do this. When it is necessary to use pesticides as an IPM tool, how do you choose a pesticide – whether it is organic, conventional, or biological – that poses the least risk?

Practices that help reduce risk to beneficial insects

No matter how hazardous or toxic any substance is, insects are only at risk if they are exposed to that substance. By using integrated pest management practices like crop rotation, sanitation, and scouting for pests, you can reduce the number of pesticide applications needed to manage pests. Making fewer pesticide applications is a great way to start protecting beneficial insects. Some pesticides are particularly dangerous to insects because they linger so long in the environment after they are applied (have a long residual), posing a greater risk. Other pesticides quickly break down in the environment after being applied to plants, so they pose less risk.

Bee pollinating a cucurbit flower
Wild bees are important pollinators of cucurbit flowers. We can thank them for many of our pumpkins, squashes, cucumbers, and melons.

Being careful about when you apply a pesticide can also reduce the likelihood that a beneficial insect will be exposed to it. Bees are less active at certain times of day (especially early morning and evening). However, some wild bee species forage at different times of day. For example, squash bees are early risers, and can be found visiting squash, pumpkin, and cucumber flowers before honey or bumble bees are active. Check the area where you plan to apply a pesticide, and pick a different time if bees are present. Some pesticide labels require that you do not apply that product while bees are foraging. Some pesticides will still harm bees that visit a flower some time after the pesticide is applied. Avoiding pesticide applications when plants are flowering will provide additional protection to beneficial insects, but may not be practical on all crops.

Where you apply pesticides also matters. Have you planted some habitat for beneficial insects? Prevent pesticide spray drift into these habitats. Are there flowers blooming amongst the grass on the orchard floor? Mowing them before you spray the fruit trees overhead could make insects less likely to visit during or right after you spray.

Resources to consult

First, read the pesticide label (and follow it). The label is the law and will have instructions on how to protect pollinators and other non-target organisms when using a pesticide.

If you know the pesticides you are considering, and especially if you know the specific natural enemies you are trying to protect, you can find some good information from companies that sell beneficial insects, or pesticides. I am aware of searchable databases or charts describing pesticide compatibility from four companies that sell (mostly) arthropod and nematode natural enemies: Agrobio, Biobest, BioWorks, and Koppert.

EIQ stands for Environmental Impact Quotient. You can read more details on the NYSIPM website, but in a nutshell the EIQ quantifies the risks of pesticides. You can use the EIQ calculator on our website to compare these numbers for different pesticides at the rates you plan to use them. The higher the number, the higher the risk. There are different components to the EIQ; risks to consumers, workers, and the environment (ecological). The ecological risk includes risks to natural enemies (as well as fish, birds, and bees). The EIQ calculator will give you an overall EIQ value as well as values for each category of risk (consumers, workers, ecological). Or, you can download this spreadsheet of EIQ values for pesticides, and sort by values for bees or beneficials (columns P and Q).

The University of California IPM Program’s pesticide active ingredients database summarizes the toxicity of some pesticides (including insecticides) to natural enemies and pollinators, as well as other hazards.

The Cornell Pollinator Network produces Pollinator Protection Guides for an increasing number of crop groups to help you understand the toxicity of different pesticide active ingredients to bees.

orange and black-striped fly with large eyes perches on small white flowers
Larvae (maggots) of this hover fly are excellent aphid predators. Killing your hover flies with pesticides could contribute to an aphid outbreak.

A few pesticides to avoid

You’re using good IPM, and you still need to use an insecticide. You’re trying to choose. I used information I collected from a few different sources (listed at the end of this post) to categorize some insecticides as “most” or “moderately” harmful. These are not exhaustive lists.

Most harmful to beneficial insects:

  • Carbaryl – active ingredient found in some products called Sevin
  • Neonicotinoids – active ingredients include imidacloprid, acetamiprid, thiamethoxam and may be found in such products as Admire, Assail, and Actara; In NY many products with these active ingredients are now classified as restricted use, so only certified pesticide applicators are allowed to buy or use them.
  • Natural pyrethrins – PyGanic is one product with this active ingredient; similar to synthetic pyrethroids, but this active ingredient degrades quickly in the environment (short residual)
  • Synthetic pyrethroids – active ingredients include bifenthrin, cypermethrin, lambda-cyhalothrin, permethrin, and others; can be found in products called Sevin, Eight, Warrior, and others; similar to natural pyrethrins, but last much longer in the environment (long residual)
  • Spinetoram – Radiant is one product that contains this active ingredient; a synthetic version of spinosad, but more toxic to beneficial insects than spinosad

Moderately harmful to beneficial insects:

  • Azadirachtin – active ingredient found in products such as Aza-Direct, Azaguard, Neemix
  • Bifenazate – active ingredient found in products such as Acramite
  • Chlorantraniliprole – active ingredient found in Coragen; among natural enemies, parasitoid wasps are probably most at risk. There may be some synergistic effects on bees when combined with other pesticides (see Cornell Pollinator Protection Guides)
  • Indoxacarb – active ingredient found in products such as Avaunt
  • Insecticidal soaps – active ingredient is potassium salts of fatty acids and can be found in M-Pede and many other products; most harmful to soft-bodied insects (including predatory mites), while beetles may be less susceptible
  • Spinosad – active ingredient in Entrust; similar to spinetoram, but it is the natural version of this chemical; not as toxic to beneficial insects as spinetoram

So what are the alternatives?

Remember that pesticides, by definition, are toxic to some living things; that’s why they kill and repel pests. There is no such thing as a completely safe pesticide. But here are a few insecticides that are gentlest on beneficial insects. And let me reiterate: Reducing the use of pesticides through good IPM is the best way to protect insects from pesticides.

  • Beauveria bassiana – several strains of this fungus are active ingredients in different insecticides, including BotaniGard
  • Bt or Bacillus thuringiensis – bacterial active ingredient in pesticides such as Agree, Dipel, and others; quite specific to the insect groups specified on the label; different subspecies are effective against different groups of insects
  • Flonicamid – active ingredient in Beleaf
  • Horticultural oils – there are many different active ingredients that fall in this group; may be more toxic to bees than to natural enemies, but require direct contact with the insect
  • Cordyceps (formerly Isaria or Paecilomyces) fumosorosea – another fungal active ingredient found in products such as PFR-97
  • Clarified hydrophobic neem oil – Note that “whole” neem oil contains azadirachtin (which I listed in the “moderately harmful group”), while clarified hydrophobic neem oil does not. Azadirachtin is extracted from neem oil, leaving the clarified hydrophobic neem oil behind.
Small insect with a black and white diamond pattern on its back on a sunflower petal
This cute little insect is a minute pirate bug. In addition to munching on pollen, it will also eat small pests like thrips, mites, and small caterpillars.

A few reminders…

  • Remember that the information in this post is not a substitute for a pesticide label. The label is the law, and you must read and follow the label of any pesticide you are using. Laws and labels change. It is your responsibility to use pesticides legally. Trade or company names used here are for convenience and information only; no endorsement of products or companies is intended, nor is criticism of unnamed products or companies implied.
  • For questions about pesticide use, regulations, and safety, contact the Cornell Cooperative Extension Pesticide Safety Education Program. If you live in New York State, you can find labels for pesticides that are registered in NY at the DEC’s NYSPAD website.
  • Just because a pesticide isn’t on the “most” or “moderately” harmful lists above, does not mean it is harmless to insects. These lists are not exhaustive, and for some products insufficient information exists.

  Sources consulted:

 

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program. Special thanks to Diana Obregon Corredor for providing review and input.

This work is supported by NYS Departments of Environmental Conservation and Agriculture and Markets.

agriculture, IPM

Biopesticide modes of action

Diagram showing an unhappy-looking caterpillar that has stopped eating a leaf. Blue diamond shapes and pale blue rectangles with smiling faces are also on the leaf.
Biopesticides include microorganisms, plant extracts, and other naturally-derived compounds that control pests.

Biopesticides are one aspect of biological control. The active ingredients in biopesticides include microorganisms (microbes), plant extracts, and naturally-occurring chemicals (like potassium bicarbonate). As a result, some of the ways they control pests (their modes of action or MOAs) are different from conventional, synthetic chemical pesticides. Also, many of them have several MOAs, and not all MOAs apply to all pests listed on the label. If a biopesticide contains live microbes, and especially if its MOA requires the microbes to stay alive on the plant for some period of time after application, this also has important implications for how the product is stored and applied. Understanding the mode of action of a product will help you get the most out of it.

I like to break down biopesticide MOAs into the following categories:

Diagrams - Tiny spores of insect-killing fungi land on the body of an insect, germinate, infect the insect, grow throughout its body, and eventually kill it. Below, a diagram shows blue spores contacting a yellow rectangle with a frightened face, representing a pathogen. The spores grow and kill the pathogen.
Eat – Some biopesticides contain living spores of a fungus (blue). These spores need to land on the insect pest or plant pathogen (yellow rectangle). Then they germinate (like a seed), invade and grow, eventually killing the pest. If the humidity is high enough, the fungus may even produce more spores and spread to other pests.

Eat – live microbe grows on/in pest

Biopesticides with this MOA can work against insect pests (e.g., products that contain Beauveria bassiana) or plant diseases (e.g. Contans, which contains Paraconionthyrium minitans strain CON/M/91-08). Many biopesticides with this MOA contain fungal spores. These spores will germinate once they land on the insect or disease-causing pathogen, and may have temperature and/or humidity requirements for germination. Make sure you store the product correctly, confirm compatibility with other products before tank mixing or applying, and apply under recommended environmental conditions.

 

Diagram - A caterpillar eats and is sprayed with a bioinsecticide (blue diamonds), and then dies. Plant pathogens (yellow rectangles) are poisoned by biopesticide microbes (blue rectangles) and the antimicrobial compounds they produce (blue droplets).
Poison – Some biopesticides (blue diamonds or blue smiling rectangles with droplets) work much like conventional chemical pesticides. They directly kill or otherwise inhibit the insect pests (like this caterpillar) or plant pathogens (yellow rectangles with frightened faces) when they contact it or are eaten by it.

Poison – biopesticide (or its products) kills the pest directly

Biopesticides with this MOA can work against insect pests (like products containing Bacillus thuringiensis) or plant diseases (e.g., Double Nickel containing Bacillus amyloliquefacies strain D747, or products containing potassium bicarbonate). Obviously, potassium bicarbonate products do not contain live microbes. Some biopesticides that poison pests do have live microbes that continue to produce antimicrobial products after they are applied. Others work because of the compounds the microbes produced while the biopesticide was being made.

 

Green leaves covered with smiling blue rectangles. Yellow rectangles with angry faces are next to the leaves.
Keep out – Some biopesticides contain microbes (blue smiling rectangles) that grow on the plant. These beneficial microbes use up space and nutrients so there is no room for the pathogen (angry yellow rectangles.

Keep out – live microbe grows on plant, leaving no room for pests

Biopesticides with this MOA can work against plant disease (e.g., Actinovate which contains Streptomyces lydicus WYEC 108, or Serifel, which contains Bacillus amyloliquefaciens strain MBI 600) and may be bacteria or fungi. The microbes in biopesticides with this MOA must be alive when applied and need to be able to grow on the part of the plant that is being protected.

 

Diagram of a plant with blue smiling rectangles on both leaves and roots. Little yellow lightning bolts surround the roots and leaves.
Turn on resistance – Some biopesticides contain microbes (blue smiling rectangles) or other natural compounds that activate the plants defense system, so that it’s ready when it encounters a pathogen.

Turn on resistance – turns on the plant’s defenses before pest attacks

As far as I know, these biopesticides only work against plant diseases, but as new products are developed, or as we learn more about existing biopesticides, this may change. Some examples include Regalia (giant knotweed extract) and Lifeguard WG (Bacillus mycoides isolate J). Some of these products contain live microbes that need to stay alive (like LifeGard), while others do not. These biopesticides need to be applied before infection.

 

Diagram - The plant on the left has no smiling blue rectangles on leaves or roots. The plant on the right has these blue rectangles on roots and leaves and is larger.
Grow strong plants – Some biopesticides contain microbes (blue smiling rectangles) or other natural compounds that enable the plant to grow stronger and healthier. As a result, the plant can better withstand attack from a pest.

Grow strong plants – makes plant stronger, healthier, more resilient

These biopesticides primarily work against plant diseases. Some examples include: Serenade (Bacillus subtilis strain QST 713), RootShield (Trichoderma harzianum), and Sil-Matrix (potassium silicate). Some of these products contain live microbes that need to stay alive, while others do not (e.g., Sil-Matrix). These biopesticides need to be applied before infection.

 

Diagram - One leaf is covered with blue diamonds and smiling rectangles (bioinsecticide), but the other is not. The caterpillar is feeding on the leaf that has no bioinsecticide.
Repel – Some bioinsecticides (blue diamonds and blue rectangles with smiling faces) protect plants because they repel insect and mite pests.

Repel – pest avoids plants treated with biopesticide

Biopesticides with this MOA can work against insect pests, but perhaps only on certain insect life stages. Some products with this MOA could contain live microbes, while others do not. You can evaluate the effectiveness of products with this MOA, not by scouting for dead insects, but by looking for reduced damage or lower insect populations on treated plants. Examples include: Grandevo WDG (Chromobacterium subtsugae strain PRAA4-1 and its spent fermentation products) and products containing azadirachtin.

 

Diagram - A caterpillar eats or comes in contact with a bioinsecticide, and then stops feeding.
Stop feeding – Some bioinsecticides (diamonds and rectangles on the leaf) cause insect and mite pests to lose their appetites.

Stop feeding – stops pest from feeding; pest eventually starves

Biopesticides with this MOA can work against insect pests either by contact or ingestion and may only be effective against insects of certain ages or life stages. It depends on the biopesticide and pest. Examples include insect-killing viruses and some types of Bacillus thuringiensis products. Some products with this MOA could contain live microbes, while others do not. Live pests will still be present for some time after applying a product that works in this way, since the pests die of starvation. Watch for feeding damage to stop or a reduction in insect numbers over time to know if the product is working.

 

Diagram – Three aphids on a leaf, two of which are exposed to blue diamonds. The aphids exposed to the diamonds stay the same size. Another aphid that was not exposed grows normally.
Stop growth – Some bioinsecticides (blue diamonds in this diagram) don’t kill insects and mites outright, but they can prevent them from molting and growing into the next life stage. Pests that can’t move on to the next life stage will eventually die.

Stop growth – stops pest from growing or molting; pest eventually dies

Biopesticides with this MOA may work against insect pests either by contact or ingestion and may only be effective against pests of certain ages or life stage. It depends on the biopesticide and pest. Examples include Venerate (Burkholderia spp. strain A396) and some products containing azadirachtin. Some products with this MOA could contain live microbes, while others do not. Products with this MOA will not kill pests immediately, but will prevent them from growing or molting. Watch for insect populations to decline over time, but do not expect pests to die immediately.

 

Diagram - Two yellow moths surrounded by blue diamonds. A red heart has a line through it.
Stop reproduction – Pheromones (represented here by blue diamonds) are a type of bioinsecticide that confuses insects looking for a mate. As a result, males and females can’t find each other, don’t mate, and females don’t lay eggs.

Stop reproduction – hampers pests’ ability to find a mate or produce eggs

The two main groups of biopesticides I know of with this MOA are (1) pheromones that make it hard for male and female insects to find each other, or (2) products that reduce the number of eggs female insects lay. Grandevo (Chromobacterium subtsugae strain PRAA4-1 and spent fermentation products) is an example of the later, but may not work in this way against all ages and species of pests listed on the label. The products I know of with this MOA do not contain live microbes. This mode of action will reduce insect populations in subsequent generations, not the current one. So use it on a pest with multiple generations per season, or in combination with other MOAs.

 

Things to keep in mind:

If the biopesticide contains live microbes, make sure you…

  • store the biopesticide correctly (and for the correct amount of time); check the label.
  • confirm compatibility of the biopesticide with other products before tank mixing or applying; read the label and contact the manufacturer with questions.

In addition, if the biopesticide contains microbes that need to stay alive for some period of time after application in order to be effective, make sure you also…

  • pay special attention to the recommended optimal environmental conditions for application; start by reading the label.

Remember!

  • Biopesticides are pesticides. Their labels are the law. Read the labels and follow them, along with other pesticide application laws in your state.
  • Not all biopesticides are permitted for use in certified organic production. Check with your certifier if you have questions.

 

Questions to ask when you are considering/purchasing a biopesticide

The manufacturer or dealer should be able to tell you:

  • How does it work (MOA)?
  • Is it alive? Does it need to stay alive to work?
  • Special instructions for storage or use? (e.g., temperature, spray tank pH, time of day)
  • Is it compatible (in the tank, greenhouse, or field) with other products in use (e.g., pesticides, fertilizers)?

 

Additional biopesticide Resources

 

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program.

habitat at home

Fall is for planting…these resources can help!

A mixture of plant seedlings in plots and trays sitting on a gravel surface
Cooler days and more moisture make fall a less-stressful time for transplanting perennials.

You’ve probably heard that fall is the best time to plant perennials (including seed for perennial wildflowers). Are you planning to start or expand a planting that supports pollinators and natural enemies of pests (beneficial insects) this fall? Trying to decide what to plant? I wanted to make sure you know about some resources from NYSIPM (some of them new this summer) that can help!

Who are you trying to attract?

Red lady beetle with black spots perched on a goldenrod plant
Some lady beetle species weed on pollen, in addition to aphids and other insects.

The good news is that flowers that produce lots of pollen and nectar and provide season-long blooms (usually as part of a mixed planting) will support a diverse group of both natural enemies that eat pests and pollinators. If you want to get a bit more specific than that, you might consider checking out:

  • Natural Enemies and What They Eat in the Field – Targeting a particular pest? This chart can help you determine which natural enemies will help.
  • (New!) Pocket Guide to Beneficial Insects – This guide was created for urban growers in New York City, but fortunately all of the beneficial insects in the Guide can be found throughout NY. It will help you recognize beneficial insects when you see them.

These resources are linked from this page. The NYSIPM website is in the process of migrating, and I’ll update this link once this page moves. You can also read about “friends in the garden” (natural enemies) that you’ll find on the ground and on plants or flying through the air in previous blog posts.

Picking plants

A raised bed containing a variety of different plants (with red, purple, yellow, or pink flowers) and labels naming each plant
Choosing a mixture of flowering plants can provide season-long blooms for beneficial insects.
  • Plants for Natural Enemies (full list) – A very large spreadsheet summarizing data from university research and extension resources; Everything I could find about individual plant species and which insects (especially natural enemies) they support.
  • (New!) Plants for Natural Enemies (2 pg handout) – Much shorter table listing 26 plants (perennials and annuals) that will support natural enemies (and pollinators); Bloom times are for central NY, and may vary in other locations (especially different USDA plant hardiness zones).

These resources are also linked from this page. And I’ve written a few blog posts about choosing plants (here and here).

 

What are you planting this fall?

 

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program.

Uncategorised

Which biopesticides work? Updated resources

A caterpillar eats or comes in contact with a bioinsecticide that causes the caterpillar to stop feeding.
Some bioinsecticides cause insect and mite pests to lose their appetites. Depending on the bioinsecticide, it either needs to contact the pest or be eaten by it.

Biological pesticides (biopesticides) are pesticides with active ingredients that are considered natural. According to the EPA they “include naturally occurring substances…microorganisms that control pests…and pesticidal substances produced by plants containing added genetic material.” This last category is more often recognized as certain (but not all) genetically modified organisms (GMOs). The “naturally occurring substances” (plant extracts, some natural chemicals) and microorganisms (bacteria, fungi, viruses) are the focus of today’s post. There’s a deeper dive into how biopesticides work in another blog post.

Biopesticides can be an important tool for integrated pest management because some of them may pose less risk to people or the environment than some conventional chemical pesticides. (But always read and follow the label on biopesticides to ensure you are minimizing risks!)

If you are considering using a biopesticide as part of your IPM program, you will of course want to know whether or not it is effective against a particular pest on a particular crop. A few years ago I wrote a post about efficacy of biocontrol. With some great help, I’ve been collecting summaries of efficacy trials on biopesticides conducted by universities. These summaries are available as downloadable Microsoft Excel spreadsheets for the following crops:

  • Berries
  • Field crops
  • Grapes
  • Greenhouse, nursery, and ornamental crops
  • Hemp
  • Hops
  • Tree fruit

The Cornell Vegetables website has some excellent information about biopesticides for vegetable diseases.

Green leaf with blue rectangles with smiling faces representing microbes as natural enemies of the pest microbes (yellow rectangles with shocked faces). The blue microbes are producing blue droplets (representing antimicrobial compounds).
Microbes used to control pests are biopesticides. In this conceptual diagram, the happy blue microbes are producing antimicrobial compounds that are killing the plant pathogens (represented by yellow rectangles with shocked faces).

Once you download a spreadsheet, take a look at the ‘Notes’ sheet for some important background information, then look at the data on either the ‘Diseases’ or the ‘Arthropods’ (insects and mites) sheet. You can sort the data on either sheet by crop, pest name, name of the product, active ingredient, or other column headings. I’ve included both a simple rating of efficacy (-, +/-, +, ++), and a numerical summary that shows how much each product improved control compared to doing nothing to control the pest.

The spreadsheets do indicate whether each product was registered in New York State at the time the sheet was last reviewed. Remember that you must confirm that the product you want to use is currently registered in New York, and that the label includes your setting, crop, and pest. You can check for current registration and download NYS pesticide labels from NYSPAD.

If you are not able to open an Excel spreadsheet, please let me know and I’m happy to get you the info in a format that works for you.

 

This work is supported by NYS Departments of Environmental Conservation and Agriculture and Markets, as well as the National Institute of Food and Agriculture, Crop Protection and Pest Management Extension Implementation Program, award number 2021-70006-35672.

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program.

agriculture

EPNs: Good worms

light brown dead grub in a petri dish broken open and surrounded by hundreds of tiny, white, crescent-shaped nematodes
Insect-killing nematodes (tiny white crescent) emerging from a dead insect larva. Photo credit: Peggy Greb, USDA Agricultural Research Service, Bugwood.org

Nematodes are tiny worms. While some of them can damage plants, some prefer to eat insects, and these “good worms” (entomopathogenic nematodes is the technical term, but we can call them EPNs for short) can be helpful biocontrol agents. Teresa Rusinek (Cornell Cooperative Extension eastern NY Commercial Horticulture Program) wrote a guest blog post about her work testing EPNs for control of wireworms in sweet potatoes. Elson Shields (Cornell Entomology) has spent many years perfecting the use of persistent EPNs that are native to New York in agricultural fields where they control insect pests. Kyle Wickings is my go-to expert on using EPNs to manage white grubs in turf. A former graduate student in Kyle’s lab (Max Helmberger) made an amazing video describing the life cycle of EPNs. John Sanderson is the Cornell guru of greenhouse biocontrol (including EPNs for greenhouse insect pests).

So many people have developed so many great materials on EPNs, the purpose of this post is to point you to some of these great resources. Why re-invent the wheel? And if I’ve missed something, please let me know!

John Sanderson (Cornell University) has done some great work evaluating different EPN species for controlling insect pests in greenhouses. You can watch a webinar summarizing this work here.

Carol Glenister (IPM Laboratories) and Elson Shields (Cornell University) did a presentation on “Getting the Most Out of Beneficial Nematodes in Organic Production” for the UMass Amherst Extension Vegetable Program. You can watch the recording on YouTube, and you can read their answers to frequently asked questions online.

Screen shot of Grub ID homepage including the url: grubid.cals.cornell.edu
Proper identification is essential to good IPM, and Kyle Wickings’ Grub ID key helps you do just that.

Need help identifying your white grubs (a critical first step to using EPNs effectively in your lawn)? Kyle Wickings developed a simple key.

Are you concerned about grub damage in your home lawn? Put back that pesticide bottle, and start by scouting and identifying grubs, then apply some EPNs (only if you need them). You can find all the details here.

white grub on soil with a few grass plants nearby
Count how many white grubs you actually have per square foot (and identify them) before deciding if an EPN application would help.

If you are growing alfalfa, Elson Shield’s lab has all the information you need to successfully use EPNs to control alfalfa snout beetles, starting with an overview, and including detailed resources to help you be successful.

Wondering if EPNs can help you control fruit and vegetable insect pests? In consultation with my colleagues, I developed a summary of what we know about which fruit, vegetable, and ornamental pests you are likely to be able to manage with EPNs. More research is ongoing, so this list will continue to evolve.

This work is supported by NYS Departments of Environmental Conservation and Agriculture and Markets.

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program, but was only possible due to the great work done by colleagues. All images are Amara’s, unless otherwise noted.

agriculture, habitat at home, home gardens, ornamentals, vegetables

Know your friends…on the ground

Small clump of blue-green grass surrounded by some bare ground and weeds
We may not spend a lot of time looking at the ground, but there are plenty of friendly insects living at the soil surface and taking shelter in plants like this little bluestem grass that don’t produce pollen-rich flowers, but still support beneficial insects.

In August I wrote about some of the friendly insects that might be visiting your garden this summer. I promised to write more about the natural enemies of pests that you might find at ground level. That time has come! Because these insects (and some other arthropods) live at or near the soil surface, you’re much less likely to see them, unless you happen to be cleaning out a garden bed this fall (which is not actually recommended). Also, they may be more active at night. But they are still doing lots of good things in your garden or on your farm, so they’re worth knowing about.

Rove beetles

Black beetle with a long segmented abdomen that protrudes beyond the short wing covers that look like a cape.
Rove beetles have wing covers that are much shorter than the rest of their body. Image courtesy of Joseph Berger, Bugwood.org.

These beetles live in the soil or at the soil surface and they eat lots of different soil invertebrates, including pests like slugs, snails, thrips, and eggs of other insects. They also eat seeds, so they could help reduce your weed seed bank, too. Like other beetles, they have hard covers over their wings called elytra. Because these covers are much shorter than their bodies, I think it makes them look like they are wearing little capes.

 

Carabid beetles

Black beetle crawling on the ground
Ground beetles may not look very exciting, but they’re great predators to have in fields and yards. Image courtesy of Mary C Legg, Bugwood.org.

Also called ground beetles, this large group of insects mostly live on the ground, and tend to have prominent jaws and move very fast. Their speed makes them great predators of many insects, as well as snails and slugs. Depending on the species, they may also eat seeds. They like to spend the winter in sheltered places including perennial grasses that grow in clumps. In the spring, they can travel almost 200 feet from these grassy shelters (Landis et al. 2000. Annual Review of Entomology 45:175-201). They come in different sizes, but tend to be darker colored.

On the left a black ground beetle with large jaws, and on the right a ground beetle with large jaws that is brown on top of its body and iridescent green on the underside of its body
Just a few more examples of ground beetles, because they’re so cool!

Centipedes

brown centipede with one pair of legs per body segment
Centipedes may not be so pretty to look at, but they’re good predators to have around. Image courtesy of Joseph Berger, Bugwood.org.

They may not look as friendly as lady beetles, but centipedes are also generalist predators that eat lots of invertebrates (including pests) in the soil. In case you were wondering, the difference between a centipede and a millipede is that centipedes have only two legs (one pair) on each segment of their body, while millipedes have four legs (two pairs) per body segment. But they can move pretty quickly, so it’s understandable if you don’t have time to count.

Spiders and harvestmen

From left to right – black and yellow spider, cream-colored spider on a red flower eating a bee, brown daddy long legs on green foliage.
These are just a few of the eight-legged friends you might find in your garden or fields. Some species you’re more likely to find on plants, and others spend more time on the ground.

I wrote about spiders in my previous post, but many species live on or near the ground. Both are good predators, and friends you’d like to have in your fields or garden. Technically, harvestmen (also called daddy long legs) are not spiders, but they do have eight legs. Because they don’t have an obvious “waist” they appear as though their head and body are a single “blob”.

Fireflies

Adult firefly, mostly black with some orange markings
Adult fireflies are more easily recognizable, even when they aren’t lit up. Image courtesy of Whitney Cranshaw, Colorado State University, Bugwood.org.

Yes, you read that correctly. When they are immature, fireflies (or lightening bugs, depending on where you grew up) look a bit more like worms than beetles (which is what they actually are). They live on the ground (especially in places with more moisture) and feed on invertebrates with soft bodies, including both snails and insects. Although we tend to notice them when they are flying, adult fireflies (depending on the species) also spend plenty of time on the ground, and may or may not be predators. The Xerces Society has some really good information about fireflies and their conservation.

immature firefly with distinct body segments. Looks sort of like an armored worm, but with six legs
Immature fireflies may not be so familiar, but are good “friends” because they eat soft-bodied invertebrates, including pests. Image courtesy of Gerald J. Lenhard, Louisiana State University, Bugwood.org.

So remember, not everything that creeps or crawls through your fields or garden is a problem. There are lots of friendly insects (and other arthropods) that can help you with pest control. Take a closer look and you might be surprised!

 

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program. All images are hers, unless otherwise noted.

This work is supported by:

  • New York State Department of Agriculture and Markets
  • New York State Department of Environmental Conservation
  • The Towards Sustainability Foundation
agriculture, home gardens, IPM, ornamentals, pollinators, vegetables

Compatibility: Pesticides and natural enemies of pests

Green insect with lacey wings
Lacewings (especially larvae; this one is an adult) are great natural enemies of pests. You want to keep them happy and healthy!

Natural enemies of pests are going to help you out with pest control, so when you are applying pesticides, it’s in your best interest to choose products that will have the least impact on them. Two quick points before we get into details for where to find this information:

  1. Remember that the information in this post is not a substitute for a pesticide label. The label is the law, and you must read and follow the label of any pesticide you are using. Laws and labels change. It is your responsibility to use pesticides legally. Trade names used here are for convenience only; no endorsement of products is intended, nor is criticism of unnamed products implied. For questions about pesticide use, regulations, and safety, contact the Cornell Pesticide Management Education Program: pmep_webmaster@cornell.edu.
  2. A great way to protect natural enemies is by following the steps for IPM. Preventing pests (e.g., through cultural strategies and exclusion), scouting to detect pests early when populations are low, and proper identification of pests will help you reduce your need to use pesticides and can save you money. Win win!

Ok, let’s assume you’re doing good IPM and you’ve gotten to the point where you need to choose a pesticide. How do you make the best choice for protecting natural enemies? Here are a few options. (Note that I did post about this about 2 years ago. I’ve learned more, so I thought an update would be in order.)

Read the label

This should go without saying. You should be doing this anyway when you are considering using a pesticide. The label may contain information about the compatibility of a pesticide with either natural enemies or pollinators. And of course it will contain important information about how to minimize risks to yourself and the environment when you use it.

EIQ

EIQ stands for Environmental Impact Quotient. You can read more details on the NYSIPM website, but in a nutshell the EIQ puts a number on the risks of pesticides at the rates they are applied in the field. You can use the EIQ calculator on our website to compare these numbers for different pesticides. The higher the number, the higher the risk. There are different components to the EIQ; risks to consumers, workers, and the environment (ecological). The ecological risk will include risks to natural enemies (as well as fish, birds, and bees).

Pocket IPM Greenhouse Scout App

The Greenhouse Scout app provides information for doing IPM in greenhouses, including pest insects, beneficial insects, application technology, and pesticide interactions. It also gives you a place to record scouting results and track product applications.
A screenshot from the home screen of the Pocket IPM Greenhouse Scout App. You can find information about compatibility with natural enemies under either “Beneficials” or “Pesticide Interactions”.

Temporary update: As of January 2024, this app is in the process of being updated and is not currently available. Hopefully a new and improved version will be available again soon!

Especially if you are growing in a greenhouse and releasing a lot of natural enemies, you may find this app helpful. In addition to providing information about compatibility of pesticides with arthropod natural enemies you may be releasing, you can also use it to help you keep records of scouting and product applications.

 

Cornell Guidelines

If you are a commercial producer, hopefully you are already utilizing the Cornell Guidelines, as they are a wealth of information on many subjects. At least some of them also include information on the toxicity of different pesticides to natural enemies. For example, if you have the grape guidelines, check out Table 4.2.2 for insecticide toxicity to natural enemies.

Websites and apps from companies that produce natural enemies

Companies that sell natural enemies (especially predatory and parasitoid arthropods for greenhouse pest control) have an interest in making sure that customers don’t inadvertently kill the natural enemies they buy with pesticides they are applying. I am aware of searchable databases, apps, or charts describing pesticide compatibility from four companies that sell (mostly) arthropod and nematode natural enemies: Agrobio, Biobest, BioWorks, and Koppert. If you know of some I’ve missed, please let me know! There are of course other companies that supply natural enemies. Here I’m focusing on resources that help you choose pesticides to conserve natural enemies.

Agrobio

This website is also available as an app for Android (but not Apple) devices. To use it, start by clicking Organisms selection and choose the natural enemies you want to conserve. Then, click Ingredients selection and choose the pesticides you are thinking about applying. You can only search active ingredients, not product names. Finally, click Query. Use the legend to help you interpret the table that’s produced.

Biobest

Biobest has put their compatibility information into an app for Android and Apple devices. Select pesticides by either active ingredient or commercial product name. Then, search for the name of the Beneficial organism you want to conserve. Note that there are a lot of pesticide/natural enemy combinations for which toxicity data just aren’t available. If you select a pesticide, then natural enemies for which no data are available will be grayed out in the Beneficial organism list. As you check boxes next to pesticides and natural enemies, a chart is automatically generated. The results include information on toxicity to different life stages of the beneficial organisms and persistence of the product.

BioWorks

BioWorks provides a table of the compatibility of their products with pesticides, fertilizers, and adjuvants. You can filter the table by several criteria to find the information you’re looking for.

Koppert

This website is also available as an app for Android and Apple devices. Start by entering the name of the Beneficial organism you want to protect. You can search by either the Koppert product name, or the Latin (scientific) name, but you can’t select from a drop-down menu. Just start typing. Then, choose the Agent (pesticide you are considering applying), by either trade name or active ingredient. Again, you need to know the name; you can’t select from a drop-down list. Start typing, and then check the box next to the product you are interested in. Click Results and be sure to click on ‘Legend’ at the bottom to help you interpret the table. There is also a more complete explanation of information in the legend under Info.

Some caveats about these websites

Admittedly, finding information about conserving natural enemies that are not commercially available for release (e.g., in greenhouses) has some challenges. These websites tend to focus on what you can buy and release, rather than on what may be naturally occurring in a field. Although sometimes there is some overlap. These apps/websites don’t include all natural enemies, and data aren’t available for all natural enemy/pesticide combinations. Also, these websites/apps usually list natural enemies by scientific names. Do you know what the scientific name of a lacewing is? I didn’t before I started this job!

To help with this last barrier, I created a chart (also below) to help you figure out what scientific names you should look for on these websites/apps if you want to conserve a particular natural enemy. It also includes information about which pests the natural enemies target, whether they are commercially available, and whether they are naturally occurring (not necessarily native) in NY.

Arthropod and nematode natural enemies

Can I buy them? Found in NY? If I want to conserve this beneficial arthropod… (whose scientific name is…) that helps me control… I should look for these names on the compatibility apps: 
yes yes aphid midges Aphidoletes aphidimyza aphids Aphidoletes aphidimyza
some yes beetles that are predators (for example, rove beetles, ground beetles, and others) Coleoptera is the scientific name of the insect group that includes all beetles. The following families are generally predatory: Coccinellidae (lady beetles), Carabidae (ground beetles), Staphylinidae (rove beetles), Cantharidae (soldier beetles), Melyridae (flower beetles) many insect pests Coleoptera is a beneficial insect listed on at least one compatibility app. However, some coleoptera are pests. And, since this is such a broad group, the compatibility information provided may not be correct for all beneficial beetle species.
yes hover flies, syrphid flies Syrphus spp, and many, many others aphids Syrphus spp.; Syrphus corollae; Episyrphus balteatus
some yes lacewings Chrysoperla spp. and some others aphids, insect eggs, small larvae Chrysopa carnea = Chrysoperla carnea; Chrysoperla spp.
some yes lady beetles Coccinellidae aphids, mites, small insects, insect eggs Coccinelidae, Coccinella 7-punctata, Hippodamia convergens
some yes minute pirate bug Orius insidiosus insect eggs, small caterpillars, thrips, mites, aphids Orius laevigatus may be a reasonable proxy; Orius spp.; Orius insidiosus
yes yes nematodes Steinernema spp., Heterorhabditis spp. thrips, fungus gnats, shore flies, some grubs Nematodes (note that this is a very broad category and it’s possible there are differences among species), Heterorhabditis bacteriophora, Steinernema, Steinernema feltiae, Steinernema carpocapsae
some yes parasitoid wasp Aphidius spp. aphids Aphidius spp., Aphidius colemani, Aphidius matricariae, Aphidius ervi
some yes parasitoid wasp Eulophidae, Diglyphus spp. leafminer larvae Diglyphus isaea
yes yes parasitoid wasp Braconids, Dacnusa sibirica leafminers Dacnusa sibirica
yes parasitoid wasp Aphelinidae, Aphelinus semiflavus aphids on potatoes Aphelinus abdominalis or Aphelinus mali may be reasonable proxies
yes yes predatory gall midge Feltiella acarisuga spider mites Feltiella acarisuga
some yes predatory mites Amblyseius (= Neoseiulus) fallacis, Typhlodromus spp., and probably others thrips, whitefly, pest mites; may vary among natural enemy species Amblyseius californicus, Amblyseius cucumeris, Amblyseius swirskii, Phytoseiulus persimilis are sold commercially and may be good proxies for the pesticide compatibility of naturally-occurring predatory mites
yes yes spined soldier bug Podisus maculiventris many immature insects, including many species of caterpillars Podisus maculiventris
 

some

 some trichogramma wasps Trichogramma spp. moth eggs Trichogramma spp., Trichogramma brassicae, Trichogramma cacoeciae, Trichogramma evanescens, Trichogramma pretiosum

Other species of interest…

Can I buy them? Found in NY? If I want to conserve this beneficial insect… (whose scientific name is…) that helps me control… I should look for these names on the compatibility apps: 
yes yes bumble bee Bombus spp. NA – pollinator Bombus spp., Bombus terrestris
yes yes European honey bee Apis mellifera NA – pollinator Apis, Apis mellifera

Notes:

Different strains or populations of these natural enemies are sold by different companies and each population may differ from natural populations. Each company is most likely to report compatibility data that applies to their population. It’s not perfect, but it’s a start.

When the first word in the scientific name of an insect (e.g. Trichogramma) is followed by the designation ‘spp.’, it means multiple species that all belong to the same genus. Some compatibility information is given for only the larger group (e.g., Aphidius spp. or Syrphus spp.).

Natural enemies that are pesticides (active ingredients are microorganisms, i.e., fungi, bacteria, viruses)

If I want to conserve this microbial natural enemy… (whose scientific name is…) that helps me control… I should look for these names on the compatibility apps: 
Bt Bacillus thuringiensis (various strains are available, and they control different pests) many caterpillars and some immature beetle and fly pests (target pest varies by strain) Bacillus thuringiensis
entomopathogenic fungus Paecilomyces fumosoroseus = Isaria fumosorosea, Beauveria bassiana, Metarhizium anisopliae (= M. brunneum) (various strains) many insects (target pest depends on fungal species and strain) Paecilomyces (=Isaria) fumosoroseus, Beauveria bassiana, Metarhizium anisopliae (= M. brunneum)
fungi that attack plant diseases there are multiple species, including Trichoderma harzianum (several strains) Plant pathogens (the target pathogen depends on the fungal strain) Trichoderma harzianum T-22 is the only fungal natural enemy I found on these apps, so far. It is unlikely that its compatibility is representative of other fungi that are natural enemies.

Notes:

Different strains or populations of these microorganisms are sold by different companies and each of these populations may differ from natural populations. Each company is most likely to report compatibility data that applies to their population. It’s not perfect, but it’s a start.

In these apps/websites, the microbial active ingredient may be listed as the natural enemy (e.g., Paecilomyces fumosoroseus on Biobest website), but sometimes it’s only listed as a pesticide active ingredient. For compatibility of biopesticides with chemical pesticides, you should start by reading the label, then seek information provided by the manufacturer. I am starting to create biopesticide profiles that include available compatibilitiy information for these products.

All tables were assembled by Amara Dunn, NYSIPM using information from Natural Enemies of Vegetable Insect Pests (Hoffman & Frodsham) and were last updated January 2020.

Give it a try!

Imagine you were considering using one of the following active ingredients:

abamectin

acequinocyl

fenpyroximate

…to control spider mites. (Of course, before you did this, you’d read the labels and be sure that the use you were considering was legal!) If you were concerned about hurting parasitoids that help with aphid control (for example, the species Aphidius colemani and Aphidius ervi) which of these active ingredients would be the best choice (from a compatibility standpoint)?

 

Go ahead!

 

Look it up!

 

A note about microorganisms as natural enemies

Green leaf with blue rectangles with smiling faces representing microbes as natural enemies of the pest microbes (yellow rectangles with shocked faces). The blue microbes are producing blue droplets (representing antimicrobial compounds).
Microbes used to control pests are biopesticides. In this conceptual diagram, the happy blue microbes are producing antimicrobial compounds that are killing the plant pathogens (represented by yellow rectangles with shocked faces).

There are a few “natural enemies” on this chart that are actually biopesticides, and I have listed them separately. Remember that microorganisms (fungi, bacteria, viruses) that are natural enemies of pests are biopesticides. A few of them can be found in the websites/apps summarized above. There are two compatibility questions when it comes to using biopesticides with living microorganisms as active ingredients: (1) Will this biopesticide harm other natural enemies (e.g., predators and parasitoids)? and (2) Will the living microbe in this biopesticide be killed by other pesticides I might use? The websites/apps have some information about the compatibility of biopesticides with arthropod natural enemies. If you’re wondering about the compatibility of biopesticides with other pesticides, that may be a topic for another post (so many posts to write, so little time!). I’ll just offer two quick pieces of advice here:

  1. Read the label of the biopesticide. If it doesn’t contain compatibility information (for use with other pesticides) or doesn’t answer your questions about compatibility with other natural enemies, contact the manufacturer to get your questions answered.
  2. If you happen to be using one of their products, BioWorks describes the compatibility of their products with other pesticides, and this information is linked to individual product pages.

And what about the bees?

Take a look at the resources created by the Pollinator Network @ Cornell. They have prepared decision-making guides for several crops already, with more to come.

 

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program. All images are hers, unless otherwise noted.

agriculture, habitat plots, home gardens, IPM, ornamentals, pollinators, vegetables

Creating habitat for beneficial insects: Time, money, and weeds

On the left is a picture of a woman in a sundress and straw hat standing in the middle of a sunny sunflower field with her arms raised in the air. Written at the top of the picture is the title “What I thought establishing habitat for beneficial insects would be like…”. On the right is a picture of three people, either on their hands and knees or bending over, pulling weeds (including dandelions) that are several feet tall. This picture has the title: “What it’s actually like.”In December, I updated you on how perennial wildflowers and grasses were establishing in our beneficial insect habitat plots during the 2019 growing season. As I wrote that post, I quickly realized that there was too much good information for just one post. So here’s the rest of the story when it comes to plant establishment – time, money, and weeds.

Before I get started, below is a quick reminder of what our treatments were. You can read all the details here.

Treatment Description
A Spring transplant, no mulch
B Spring transplant with mulch
C Spring direct seed
D Buckwheat cover crop, then fall transplant
E – control Whatever was growing there, just keep it mowed
F Soil solarization, then fall direct seed
G Herbicide and tillage, then fall direct seed

Weed control

One thing that has surprised me about this project (although others certainly gave me fair warning) was how big a role weed management plays in establishing habitat for beneficial insects. It’s definitely still a struggle in our plots.

Bryan Brown did weed assessments for us in May and September of 2019. The graph below shows the average percent of the area of each plot covered by either weeds (orange) or beneficial habitat flowers and grasses (blue).

Bar graph shows the average percent of plots covered with either weed or beneficial habitat plants in May 2019. Weed control in the treatment (B) where transplants were mulched had the best weed control. The worst weed control was in treatment D, where seedlings were planted in Fall 2018 after a buckwheat cover crop.
Mulching provided the best weed management when plots were assessed in May of 2019. Each bar shows the average of four plots per treatment, and has an error bar showing variation among these plots (one standard error above or below the average for the treatment).

This was before we did any hand-weeding. By far, the plots that were mulched in Spring 2018 (treatment B) had the fewest weeds compared to beneficial habitat plants. You’ll also notice that in May there were still relatively few weeds in the plots where we tried to deplete the weed seed bank in the soil through solarization (treatment F) or repeated herbicide and tillage (treatment G).

Picture on the left is of treatment B (Spring transplant and mulch) and shows small wildflower plants surrounded by mulch and few weeds. The middle picture shows treatment C (spring direct seed), a weedy plot. The picture on the right shows treatment F (solarization and fall direct seed), where you can still see at least 50% of the plot is bare soil, although many small and a few larger weeds are visible.
What some of the plots looked like on May 16, 2019 when Bryan did the weed assessment.

By September 2019, the spring transplant treatments looked even better. Our wildflowers grew well during 2019 (with the help of some extra hand weeding). The plants we transplanted in Fall 2018 are still struggling and not nearly as large as the wildflowers in treatments A and B. I think this may have more to do with the weed competition they experienced that first fall (when we couldn’t plant for a few weeks after the buckwheat was mowed) than transplant timing. Hopefully they will catch up.

Picture on the left is of treatment A (spring transplant, no mulch) and shows tall wildflower plants with some weeds. The middle picture shows treatment B (Spring transplant and mulch), full of large wildflowers and few weeds. The picture on the right shows treatment D (buckwheat and fall transplant), where the wildflower plants are much smaller, there are more weeds, and some bare ground is visible.
What some of the plots looked like on September 19, 2019 when Bryan did the weed assessment.

There are still a lot of weeds in the direct-seeded treatments (C, F, or G). Remember that our weed management strategy in these plots is repeated mowing to control annual weeds. Over time, the perennial wildflowers and grasses should take over. But it’s not supposed to be a quick method.

Bar graph shows the average percent of plots covered with either weed or beneficial habitat plants in September 2019. Weed control in the treatment (B) where transplants were mulched still had the best weed control. The worst weed control (besides the control plot where no beneficial habitat plants were planted) was in the three treatments using spring or fall direct seeding (C = spring direct seeding, F = soil solarization and fall direct seeding, G = herbicide and tillage with fall direct seeding).
Spring transplant treatments (A and B) looked the best after their second full growing season. The fall transplants (D) had more weeds, but these plants also have been in the ground for one less growing season. I’m still hoping they will catch up. Each bar shows the average of four plots per treatment, and has an error bar showing variation among these plots (one standard error above or below the average for the treatment).

Effort

Most of the treatments we are comparing required much less work in their second year (2019) than in their first (2018). The exception is that we spent a lot more time hand weeding treatment D (buckwheat cover crop followed by fall transplanting) in 2019. Although we weeded the two spring transplanted plots the same number of times in 2019 (twice), it took longer to hand weed the plots without mulch. I’m not surprised. If you’re looking for the right establishment method for your project, you really need to ask yourself how much help you have available and when. If you can get a lot of people excited about helping you install the planting, but worry about getting consistent volunteers year after year, mulch may be the right choice for you. In the direct seeded treatments (C – spring; F – fall following solarization; G – fall following herbicide and tillage), the time input for 2019 was mowing, which was relatively quick. And we did just a little hand weeding of perennial weeds.

Bar graph shows time (in person hours) spent on each treatment for both 2018 (in blue) and 2019 (in orange). The tallest bars are for treatments A, B, and D, but most of the bar for treatment B is blue (representing transplanting, mulching, and hand weeding in 2018). For treatment D, half the bar is orange (representing hand weeding in 2019). Treatment A shows more orange than treatment B, but less than treatment D.
Transplanting (treatments A, B, and D) still takes more time than direct seeding, but the extra time we spent mulching in 2018 paid off in 2019 when we spent less time hand weeding (treatment B compared to A and D).

Costs

Nearly all of our costs were incurred in the first year of the project (2018). The only additional costs from 2019 were for gas to run the mower. We did replace a few plants in transplanted plots in Fall 2019, but we used some extra plants we had purchased in 2018. Below is the total cost of the plants and other supplies for each treatment. Transplanting will always be more expensive than direct seeding.

Treatment Costs
A $417.12
B $539.29
C $18.83
D $390.55
E $3.40
F $149.10
G $23.12

 

You may remember that we were also collecting insects. I promise I will write more about the insects we caught in another post. If you are tired of looking at snow and bare trees outside, you can see pictures of some of the insects we caught in my post from August 2019.

This post was written by Amara Dunn. All pictures were taken by her, unless otherwise credited.

This work is supported by:

  • Crop Protection and Pest Management -Extension Implementation Program Area grant no. 2017-70006-27142/project accession no. 1014000, from the USDA National Institute of Food and Agriculture.
  • New York State Department of Agriculture and Markets
  • Towards Sustainability Foundation
agriculture, habitat plots, home gardens, IPM, ornamentals, pollinators

Creating habitat for beneficial insects: How are things growing?

Planting of purple, yellow, and white flowers with blue sky in the background
Lots of flowers bloomed in 2019 in our habitat plots. Some we had planted, and some we hadn’t.

Obviously, nothing is growing right now, but I thought this would be a good time to update you on the success of our beneficial insect habitat plots during the 2019 growing season.

When things bloomed

Recall that the goal is to have at least one plant blooming all season long. We choose wildflower species accordingly, and it worked! The following table shows which months each species bloomed in 2019 (at least in the transplanted plots). An ‘X’ means the species was blooming during that month.

Wildflower May June July Aug Sep
Golden alexanders X X
Catmint X X X  X
Lanced-leaved coreopsis X X
Tall white beard tongue X X
Ohio spiderwort X X
Anise hyssop X X  X
Echinacea X X  X
Orange coneflower X X  X
Boneset X X X
Wild bergamot X X
Common milkweed X
NY ironweed X  X
Showy goldenrod  X
New England aster  X
Blue false indigo

You may notice that the blue false indigo never bloomed in 2019, which was disappointing. Most of these plants are still alive (as you’ll see later in this post). They just didn’t bloom. Maybe next year?

Here’s what each species looks like:

Plant with tiny yellow flowers arranged like Queen Anne’s Lace.
Golden alexanders (Zizia aurea)
Small purple bell-shaped flowers on stems with frosty-green leaves
Catmint (Nepeta faassinii)
Yellow daisy-shaped flowers with toothed edges
Coreopsis (Coreopsis lanceolata)
Clusters of white or pink bell-shaped flowers on top of tall stems
Tall white beard tongue (Penstemon digitalis). Obviously not all of these flowers are white!
Three-petaled purple flowers growing on plant with grass-like leaves.
Ohio spiderwort (Tradescantia ohiensis)
Small, pale purple flowers clustered at the top of a stem
Anise hyssop (Agastache foeniculum)
Pink daisy-shaped flowers with organge centers
Echinacea (Echinacea purpurea)
Large clump of daisy shaped flowers with yellow petals and dark brown centers
Orange coneflower (Rudbeckia fulgida var. fulgida)
Small white flowers in flat clusters
Boneset (Eupatorium perfoliatum)
Pale pink-purple flowers that look like small tufts on the top of stems
Wild bergamot (Monarda fistulosa)
Pale pink flowers with 5 sets of petals and a complex shape
Common milkweed (Asclepias syriaca)
Bright magenta flowers formed into small tufts at the top of the plant
NY Ironweed (Vernonia noveboracensis)
Large clump of small, bright yellow flowers
Showy goldenrod (Solidago speciosa)
Purple daisy-shaped flowers with yellow centers and very narrow petals. A small bee is visiting one of the flowers
New England aster (Symphyotrichum novae-angliae)
Pale blue-purple legume flowers. One is being visited by a bumble bee
Blue false indigo (Baptisia australis); hasn’t bloomed yet in our field. Photo credit: Ansel Oommen, Bugwood.org

Transplanted wildflowers

The wildflowers in our transplanted plots are surviving pretty well (>80%). In the plots that were transplanted in the fall after the buckwheat cover crop, the survival is a bit lower. I think this has to do with some weed control issues (more on this in a future post).

Percent of plants surviving was lowest in treatment D, but still above 80%. Survival did not change very much from Spring to Fall 2019.
How well have the transplanted wildflowers survived so far? Treatment A was transplanted in Spring 2018 and not mulched. Treatment B was transplanted in Spring 2018 and mulched. Treatment D was transplanted in Fall 2018 following a buckwheat cover crop. All have been hand weeded periodically. In both Spring and Fall of 2019 I counted plants to see how well they survived. The black lines on each bar in the graph show one standard error above and below the mean percent survival.

Some species have survived better than others, as the following chart shows. Again, we counted plants both in Spring and Fall 2019.

Bar graph showing the mean percent of plants of each species that were still alive in Spring and Fall 2019. With the exception of milkweed, all survival rates were at or above 80%, and losses were minimal from Spring to Fall.
Do some species of wildflowers survive better when transplanted? There’s a little bit of variability, but overall most are surviving pretty well.

What about the direct-seeded plots?

Only three species of wildflowers planted by seed in Spring or Fall 2018 bloomed during the 2019 season. The table below shows which months these blooms were seen (marked with an ‘X’).

Common name May June July Aug Sep
Coreopsis X X X
Blackeyed susan X X X
Partridge pea X X

Here’s what the flowers of blackeyed susan look like. The plant has much hairier leaves than the orange coneflower.

A daisy-shaped flower with yellow petals and a dark brown center
Blackeyed susan (Rudbeckia hirta)

And here’s the partridge pea:

Yellow flower with compound leaves cupped in a person’s hand
Partridge pea (Chamaecrista fasciculata)

But, I also spotted some wild bergamot, tall white beard tongue, asters, golden alexanders, and either echinacea or orange coneflower seedlings. (I haven’t honed my horticultural skills enough yet to distinguish the foliage of these last two wildflowers.)

Pictures of seedlings labeled (left to right, top to bottom) aster, golden alexanders, echinacea or orange coneflower, wild bergamot, and beard tongue.
Seedlings of some wildflowers could be identified in the direct-seeded plots by September 2019.

There were also plenty of weeds blooming throughout the summer, and many of them were providing pollen and nectar for pollinators and natural enemies. Here are just a few examples:

Four pictures showing a bee on a yellow flower, several daisy-shaped flowers with white petals and yellow centers, a yellow dandelion with a pink lady beetle on it, and a bumble bee visiting a pink clover flower
From left to right: A bee feeding on a weed in the aster family, blooming chamomile, a lady beetle on a dandelion, and a bumble bee visiting clover (that wasn’t planted).

This table summarizes when during the season different weeds were in bloom. Again, an ‘X’ indicates the weed was blooming that month.

Weed May June July Aug Sep
Campion X X X X X
Chamomile X X X X X
Clover X X X X X
Dandelion X X X X X
Vetch X X X X X
Viola X X X X X
Mustard X X X X
Deadnettle X X
Baby blue eyes X
Henbit X
Asters X X X X
Buckwheat X X X X
Oxalis X X X X
Plantain X X X X
Wild lettuce X X X X
Cinquefoil X X X
Indian hemp X X X
Redshank X X X
Chickweed X X
Galinsoga X X
Geraniums X
Sandwort X
Grass X X
Horse weed X X
Lambsquarters X X
Ragweed X X
Black bindweed X
Chicory X

There’s more!

In addition to keeping track of what bloomed from May through September, we were also still tracking costs and time spent on each plot in 2019. And of course we collected a LOT of insects. But those stories will have to wait for another post.

This post was written by Amara Dunn. All pictures were taken by her, unless otherwise credited.

This work is supported by:

  • Crop Protection and Pest Management -Extension Implementation Program Area grant no. 2017-70006-27142/project accession no. 1014000, from the USDA National Institute of Food and Agriculture.
  • New York State Department of Agriculture and Markets
  • Towards Sustainability Foundation
agriculture, augmentative biocontrol, IPM

Cereal Leaf Beetle Biocontrol Project Underway

This month’s post is about a project being led by Jaime Cummings, the Field Crops and Livestock IPM Coordinator at NYS IPM. The goal is to improve biological control of the cereal leaf beetle, a pest of small grains. Before we tell you about the biocontrol project, you’ll need some background information on this pest and the other management options available. You can use the following links to navigate to each section of this post:

Cereal leaf beetles and damage they cause

Scouting for cereal leaf beetle and deciding when to spray

Biocontrol of cereal leaf beetle

Our project: Improving biocontrol of cereal leaf beetle

Cereal leaf beetle damage on the flag leaf of a winter wheat plant. (Photo by J. Cummings, NYS IPM)

Cereal leaf beetles and the damage they cause

The cereal leaf beetle (CLB), Oulema melanopus, can be a significant pest of winter and spring small grains production in NY, especially in parts of western NY.  This invasive species was first detected in Michigan in 1962, and has since become established in many grain producing states in the US, despite quarantine and pesticide eradication efforts in the 1960’s and 1970’s.

Left: a black beetle with a red middle (thorax), sitting on the leaf of a small grain crop; Right: a yellowish larva sitting on the leaf of a small grains crop
Figure 1. Cereal leaf beetle adult (A) and larval (B) stages. (Photos by J. Cummings, NYS IPM)

You may be familiar with this pest either in the larval or beetle stage (Fig. 1).  CLB has one or two generations per growing season, and the adults overwinter in hedgerows, woods or field margins.  We usually start seeing the adults move into small grains fields in April or May to lay eggs which develop into the damaging larvae.  The larger the larvae get, the more damage they inflict on the crop.  After about two weeks of feeding, the larvae drop to the ground and pupate for about two weeks before the adults emerge again.

When looking for these pests, keep an eye out for the typical larval feeding damage that looks like strips of green tissue missing between leaf veins.  Severely damaged leaves may appear skeletonized, and intense feeding pressure in a field may result in a ‘frosted’ appearance of flag leaves (Fig. 2).

green heads of winter wheat surrounded by leaves that have tan stripes on them
Figure 2. Severe cereal leaf beetle larval feeding on winter wheat. (Photo by J. Cummings, NYS IPM)

Considering that the top two leaves of the wheat/barley/oat crop are what contributes most to grain yield, severe infestations of CLB can significantly impact yield and grain quality.  Even in small grain or mixed stand forage crops, this pest can have negative effects on the yield and quality of the forage because they can significantly reduce leaf area and photosynthetic capability of the crop.

Scouting for cereal leaf beetle and deciding when to spray

It’s important to scout for this pest, usually starting in early to mid-June when larvae are first appearing.  The economic threshold for insecticide application for CLB is when you count an average of three or more larvae per plant before the boot stage or one or more larvae per flag leaf after the boot stage.  Occurrence of this pest can be inconsistent within a field, therefore plan to scout weekly and walk a random pattern throughout each field stopping at 10 random locations to count larvae on 10 plants at each location.  Because insecticides labeled for CLB target the larval stages, in order for your pesticide applications to be most effective, make sure that at least 25% of CLB eggs have hatched and that larvae are present and actively feeding when you decided to spray.  And, if you’re seeing adults in late June or beyond, it’s probably too late to spray for the larvae.  (Always follow label recommendations and restrictions when applying pesticides)

Paying attention to CLB populations in your fields via scouting is an important part of an integrated management approach for minimizing losses to this pest.  A growing degree day (GDD) model for CLB developed in Michigan determined that adult CLB begin to emerge around 350-400 GDD (base 48) to begin egg laying.

Biocontrol of cereal leaf beetle

Unfortunately, there is no specific host plant resistance available for CLB, but there are natural predators of the larvae and eggs which can help to keep the pest population in check, and possibly below the economic threshold when well-established in an area.  Lady beetles are known to prey on CLB larvae and eggs, and there is at least one egg parasite though it is not widely distributed.

There is also a CLB larval parasitoid wasp, Tetrastichus julis, which was originally introduced from Europe as a biological control agent in Michigan in 1967 (Fig. 3).  Subsequent releases into other states, including NY in 1973, have led to a sporadic establishment of this biological control parasitoid throughout small grain production areas of the US.

Tiny black wasp perched on dark brown larva clinging to a leaf
Figure 3. Tetrastichus julis, a parasitic wasp on a cereal leaf beetle larva. (Photo courtesy of Washington State Department of Agriculture)

Our project: Improving biocontrol of cereal leaf beetle

Given that CLB damage can be widespread and undermanaged in many small grains fields in NYS, and under the advice of Dr. Elson Shields (Cornell University Field Crops Entomologist), the NYS IPM program decided to try to determine the parasitism levels of CLB larvae in various locations around the state and to try to increase populations of the parasitoid in the Aurora area of Cayuga County, where the CLB tends to be a perennial pest.  The multiyear project was initiated this year, with CLB larval collections from locations in six counties.  However, there were no CLB present to collect at two of the locations, so the data collected in 2019 includes only four locations (Table 1).

Table 1.  Cereal leaf beetle collection efforts for determining parasitism levels in 2019.

Location County Collection date Crop # CLB larvae collected
Seneca Falls Seneca 6-Jun winter wheat, rye, barley 96
Aurora/Musgrave Cayuga 12-Jun spring barley 92
Ithaca Tompkins 12-Jun winter wheat, rye, barley 45
Penn Yan Yates 13-Jun spring oats and peas 110
Oriskany Oneida 11-Jun winter wheat 0
Homer Cortland 10-Jun winter wheat 0

 

At each location, a target of approximately 100 CLB larvae of all different sizes/growth stages were collected by hand from wheat, barley or oat fields.  The larvae were temporarily reared in incubation chambers on host plant leaves until approximately half of the larvae were dissected to determine baseline parasitism levels for each location (Fig. 4).

Left: Petri dishes with white filter paper and torn up leaves of oats; Right: Brown and yellow larvae of the cereal leaf beetle (some are squished) on a moist white filter paper in a petri dish
Figure 4. Cereal leaf beetle rearing chambers (A) and dissection process (B). (Photo by J. Cummings, NYS IPM)

The eggs of the parasitoid are visible when the CLB larvae are cut open under a microscope (Fig. 5).

close-up image of squashed yellow larvae. Dark head capsules are still visible, and small oblong eggs of the parasitoid can be seen next to one squished larva. The picture has the following labels: Dissected CLB larvae, and T. julis parasitoid wasp eggs from inside CLB larva
Figure 5. Dissected CLB larvae, and one with T. julis parasitoid eggs. (Photo by J. Cummings, NYS IPM)

After baseline parasitism levels were determined for each collection location, the other half of the CLB larvae were then released at the Cornell Musgrave research farm near Aurora, NY (Fig. 6).  This process will be repeated over the next few years.

Left: Hand hold an open petri dish filled with oat leaves, cereal leaf beetle larvae, and white filter paper; Right: Small dark larvae on an oat leaf with feeding damage
Figure 6. Cereal leaf beetle larvae with known level of parasitism being released in Cayuga County (Photos by J. Thomas-Murphy, Cornell University)

The goals of this project are to determine the established levels of the T. julis parasitoid around the state since the initial release in 1973, and to try to determine if we can increase its population at the research farm through consecutive releases.  From this first year of data collection, we know that the parasitoid population is low at the research farm in Cayuga County (6%) and at two of the collection sites (7% and 10%, in Seneca and Yates Counties, respectively), but was at approximately 30% at the Ithaca (Tompkins County) collection site (Fig. 7).

Graph shows that in Seneca County and Cayuga County only 7% and 6% (respectively) of cereal leaf beetle larvae were parasitized, while in Tompkins County the parasitism rate was 30%, and in Yates County the parasitism rate was 10%
Figure 7. Percent T. julis parasitized cereal leaf beetle larvae collected from various locations.

We also know that although there has been a need to spray insecticides to manage CLB at the research farm in Cayuga County and near the other collection sites, there has been no need to spray for CLB at the Ithaca (Tompkins County) collection sites.  It’s likely that the T. julis parasitoid population at the Ithaca site keeps the CLB population below economic threshold levels.  We hope that by intentionally distributing this parasitoid into an area with known CLB problems, we can establish a robust parasitoid population that may result in a reduction of necessary insecticide sprays for this pest.

This post was written by Jaime Cummings, Ken Wise, and Amara Dunn, all of the New York State Integrated Pest Management Program.