Category Archives: agriculture

agriculture

Biopesticides for tomato bacterial diseases: On-farm demos

row of tomato plants with some green fruit and a sign that says Double Nickel 1 qt/A alt. Kocide
On-farm demonstration of reducing copper applications by alternating with biopesticides to protect against tomato bacterial diseases.

Last summer I wrote about integrated pest management strategies (IPM) for tomato bacterial diseases and how biopesticides fit into strategies for managing these diseases. You’ll recall that research trials conducted at Cornell in Chris Smart’s lab indicated that you could replace some copper sprays with the biopesticides Double Nickel or LifeGard and achieve the same level of control of tomato bacterial diseases. In 2023, we wanted to demonstrate what this might look like on vegetable farms around New York State – Long Island, eastern NY, and western NY. Here’s what we observed.

 

Results from On-Farm Demos

Biopesticides are not a panacea for tomato bacterial disease problems. When disease pressure is severe and weather is favorable, bacterial diseases can be difficult to manage, even with copper-based fungicides. Canker is especially difficult to manage because the bacteria that cause the disease move systemically within the plant. Successful management of bacterial diseases in tomatoes requires the use of multiple IPM tools, including starting with clean seed and healthy transplants, and using new (or effectively disinfected) tomato stakes.

On farms that experienced tomato bacterial disease outbreaks, adding Double Nickel did not satisfactorily control bacterial disease. These farms had very uneven distribution of tomato bacterial canker across the fields, complicating comparisons between the Double Nickel alt. copper treatments and the copper only treatments. Two farms (in western NY) saw slight to moderate increases in fruit quality when they added Double Nickel sprays in between copper applications compared to applying copper every 10-14 days. This resulted in estimated 2% and 37% increases in fruit value, corresponding to an extra $19 (from nine harvests) or $72 (from four harvests) from 100 row feet of tomatoes. However, the Double Nickel sprays were in addition to copper sprays, not replacing them. We don’t know if applying copper every 7-10 days would have resulted in better disease control. On the third farm, we saw no benefit of replacing half of the copper applications with Double Nickel.

The two cooperating Long Island farms saw no bacterial disease in 2023. But replacing half of the copper applications with either Double Nickel or LifeGard still seemed to have economic advantages. We estimate that the value of their crops increased by 7% and 59%, or $244 and $1,617 per 100 row feet of tomatoes harvested four times. Note that the price for fresh tomatoes on Long Island is high compared to some other markets in NY. We used $5-$6/lb in our Long Island estimates. Also, we don’t know what would have happened if there had been a bacterial disease outbreak on these farms.

On all cooperating farms, we collected data on very small sections of the field (10-40 row feet of tomatoes). Estimated potential impacts on yield over much larger areas should be taken with a grain of salt.

Green Roma tomato fruit with both white spray residue and classic fruit symptoms of tomato bacterial canker – brown spots with a white ring around them
Tomato bacterial canker is a difficult disease to manage, even with weekly copper applications. Use of multiple integrated pest management (IPM) tools yields the best results. Photo credit: Crystal Stewart-Courtens.

 

Economics

We researched some prices for pesticides from a few different suppliers. Below are the assumptions we made to calculate some price estimates and make comparisons among some biopesticides and copper pesticides. Prices for pesticides can vary across regions and time. If you think any of these numbers are far out of line, please let Amara know!

If you are applying… and a container costs you… and you apply at a rate of… Your cost per A per application is:
Actinovate AG $115/18 oz bag 7.5 oz/A (range on label is 3-12 oz) $48.00
Double Nickel LC $85.25/1 gal 1 qt/A (recommended for tomato bacterial diseases) $21.31
LifeGard WG $148/1 lb bag 4.5 oz/100 gal and 50 gal/A = 2.25 oz/A $20.80
copper (Kocide 3000-O or Badge X2) $102/10 lb bag 1.25 lb Kocide, 1.8 lb Badge X2 (highest rate on label) $15.00
copper (Badge SC) $150/2.5 gal 1.8 pt/A (highest rate on label) $13.58
Copper (Champ Formula 2 Flowable) $139.95/2.5 gal 1.33 pt/A $9.31
copper (Cueva) $114/2.5 gal 1 gal/A (label rate is 0.5-2 gal) $46.27

As you can see, the biopesticides in the table range from fairly similar in price (Double Nickel and LifeGard) to approximately 5 times the cost of the less expensive coppers (Actinovate). Each copper application replaced with either Double Nickel or LifeGard is estimated to increase the pesticide cost by $6-$12 per acre per application. If a grower makes eight applications in a season to protect tomatoes from bacterial diseases, this would be an increase of $24-$48 per acre for the season if half of the copper applications are replaced with Double Nickel or LifeGard. If a grower adds LifeGard or Double Nickel applications to a 14-day copper spray program, the cost increase is greater. Purchasing product for four additional applications costs an extra $84 per acre, not including other costs of making more applications, like fuel, labor, equipment depreciation, etc.

 

Protecting people and the environment

Replacing some copper sprays with biopesticides can have other benefits. For example, the following table compares restricted entry intervals (REIs), label signal words, and field use ecological Environmental Impact Quotient (EIQ) for several biopesticides and copper formulations. Shorter REIs indicate a pesticide has lower toxicity to agricultural workers. The signal word shows the relative acute toxicity of the pesticide to the pesticide applicator.

 

Product Active Ingredient (%) Rate REI Signal word Field Use Ecological EIQ1
Actinovate AG Streptomyces lydicus WYEC 108 (0.037%) 12 oz/A 4 hrs Caution NA
Double Nickel LC Bacillus amyloliquefaciens strain D747 (98.85%) 1 qt/A 4 hrs none on label NA
LifeGard WG Bacillus mycoides isolate J (40%) 4.5 oz/A 4 hrs Caution NA
Serenade Opti2 Bacillus subtilis QST 713 (26.2%) 20 oz/A 4 hrs Caution 7.2
Badge SC copper hydroxide (15.36%); copper oxychloride (16.81%)3 1.8 pt/A 48 hrs Caution 40.1
Champ Formula 2 Flowable copper hydroxide (37.5%) 1.33 pt/A 48 hrs Warning 34.5
Cueva copper octanoate (10%) 2 gal/A 4 hrs Caution NA
Kocide 3000-O copper hydroxide (46.1%) 1.25 lb/A 48 hrs Caution 38.2
MasterCop copper sulfate pentahydrate (21.46%) 2 pt/A 48 hrs Danger 66.4

1 The Environmental Impact Quotient (EIQ) seeks to quantify the environmental impacts of pesticides. Higher numbers indicate more negative impacts. The values reported here are “field use” values, calculated based on the rates listed in the table. These values vary depending on how much product you use per acre. The ecological component summarizes risk to fish, birds, bees, and beneficial insects.

2 The active ingredient in Serenade Opti is in the EIQ database, while the active ingredients of the other biopesticides in this table are not. The EIQ for Serenade Opti is expected to be similar to those of Double Nickel and LifeGard because they have similar active ingredients. It may also be similar to the EIQ for Actinovate.

3 Only copper hydroxide – not copper oxychloride – was in the EIQ database, so this ecological EIQ was calculated using 32.17% copper hydroxide (sum of the percentages of the two active ingredients).

 

Other benefits of reducing copper applications on a farm could include:

  • It reduces the risk of selecting for tomato bacterial pathogens that are resistant to copper.
  • Many copper fungicides leave a visible residue on fruit, which may impact marketability if applied close to harvest.

 

Update on labels

In last summer’s post we noted that neither Double Nickel nor LifeGard included tomato bacterial canker on their labels. In New York State, formulations of these biopesticides now have 2(ee) labels that include this disease on tomatoes. Make sure you have a copy of both the original label and the 2(ee) label in your possession if you are using these products for tomato bacterial canker in NY. If you are in NY, you can find these and other labels through NYSPAD.

 

The Bottom Line

  • It is very important to use all your IPM tools for tomato bacterial disease management, especially for canker. If you are bringing canker to your field in seedlings or on tomato stakes, it will be very difficult to catch up with the disease using any pesticide if weather conditions favor disease.
  • Some biopesticides are competitively priced (per bottle and per acre) with copper formulations. Replacing a few copper applications with these products will not cost you much more.
  • Replacing some copper applications with biopesticides offers some additional benefits, including copper resistance management, and potentially reduced risk to the environment and human health.

 

 

Changes in pesticide registrations occur constantly and human errors are possible. Read the label before applying any pesticide. The label is the law. No endorsement of companies is made or implied.

 

This post was written by Amara Dunn-Silver, Biocontrol Specialist with the NYSIPM program. Thanks to collaborators Chris Smart, Professor in the School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section at Cornell University, Crystal Stewart-Courtens, Extension Vegetable Specialist, Eastern NY Commercial Horticulture Program; Elizabeth Buck, Cornell Vegetable Program; Margaret McGrath, Retired Faculty, School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section at Cornell University, and Sandra Menasha, Cornell Cooperative Extension, Suffolk County. Support for this project was provided by the NY Farm Viability Institute.

Logo for the NY Farm Viability Institute

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.

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, Christmas tree establishment IPM, IPM, ornamentals

IPM for establishing Christmas trees: Survival and growth in the first season

Rows of small Christmas trees growing in a field on a sunny afternoon; some are surrounded by wood chip mulch, some by cultivated ground, some by bare ground, and some by tall weeds.
The different weed management strategies we are comparing certainly look different in the field. But how do they impact tree growth and quality?

Back in June we introduced you to a new project comparing different methods for weed and root disease management when establishing Christmas tree seedlings. Recall that this is a collaboration among Bryan Brown, Amara Dunn, Brian Eshenaur, Betsy Lamb, and Lynn Sosnoskie. We wrapped up our first season in October, and we have a first look at some of the data. In this post, we’ll focus on tree survival and tree growth. There’s a lot more weed data!

Treatments

Let’s start with a quick reminder of the treatments we were comparing. Each row of 28 trees received the same weed management treatment. Each row was also divided into four plots of seven trees each. Each plot within a row received a different root treatment. Here’s a map of how the treatments were laid out in the field.

Weed management (in-row, within a 30” band around the row of trees; between row zones were seeded with grass and mowed 4 times) :

  • Cultivate – three times early in the season using a tractor drawn KULT Kress Argus Toolbar with sweeps, finger weeders, and a rear side-shift adjustment
  • Herbicide – conventional active ingredients (oxyfluorfen and pendimethalin applied shortly after planting, with a fall application of glyphosate) as a control treatment
  • Mow – mow about every two weeks with a walk-behind mower
  • Mulch – 3 inches of chipped shrub willow mulch
  • Untreated – No weed management at all

Root disease management:

  • ProPhyt (active ingredient: potassium phosphite) – a biopesticide applied by dipping bare roots of seedlings just before planting; mixed 1.28 fl oz in 2 gallons of water for 140 trees (11 fl oz/A if you plant 1,200 trees/A)
  • RootShield PLUS WP (active ingredient: Trichoderma harzianum Rifai strain T-22 and Trichoderma virens strain G-41) – a biopesticide applied twice (the day after planting and 7 weeks later) as a drench around each tree (24 oz/A in 171 gallons of water/A)
  • Subdue Maxx – a conventional fungicide applied twice (the day after planting and 5 months later) as a soil-directed spray (2.5 pt/A in 140 gal/A in a 6-inch band on either side of the row of trees). We made the application with a hand-pump backpack sprayer fitted with a TeeJet TTI11005 nozzle with a shield rotated parallel to the row of trees. The maximum pressure possible with this sprayer is 60 psi. After application, we applied an extra 0.45 gallon of water per plot of 7 trees with the same sprayer (280 gal/A additional water).
  • Water – 1 pt of water poured around each tree at planting, as a control.

What we measured

We’re interested in how the weed and root disease treatments impact survival, growth, and quality of these trees. Thanks to our excellent technicians, Marcus and Erik, for helping us measure all of these trees! Betsy and Amara were helping, too, but in this picture Amara is behind the camera.

A woman in a pink shirt comparing a small Christmas tree to a piece of paper, while a man in a plaid shirt measures the height of a small Christmas tree seedling; both are in a newly planted field with freshly tilled soil
Betsy and Marcus measuring trees and evaluating needle color in May.

On May 25 (about a week after planting) and again on October 6 we measured the height of each tree (from the soil to the tallest part of the tree, even if it wasn’t the leader anymore) and the diameter of the tree trunk 4 inches above the soil. In both May and October, we also rated the color of the needles using this scale. However, we only used: 2 (darkest green), 5 (medium green), 7 (paler green), and 9 (yellow or brown).

Of course, measuring and rating each tree also allowed us to take note of which trees had died (versus a few that unfortunately succumbed to “mower blight”).

What we found

Bar graph showing that trees generally survived better when treated with ProPhyt, except not if weeds were managed with herbicide. The impact of root treatment varied, depending on which weed management strategy was used.
Percentage of trees in each plot (out of seven trees total) that were still alive by October 2021, not counting a couple that were accidentally mowed. Each bar is the average of four plots for each combination of root treatment (color of bars) and weed management strategy (along x-axis). The lines on each bar show variability (one standard error above and below the mean value).

It’s too early to know for sure, but it’s possible that the root treatment that results in the best seedling survival might depend on which weed management strategy you use. For example, after just one year, the RootShield PLUS-treated trees did better than the ProPhyt-treated trees where herbicide was used, but not where the weeds were allowed to grow unchecked (‘Untreated’). We haven’t done a statistical analysis on the data, yet, but the little lines at the top of each bar are an indication of the amount of variability amongst the four plots in each treatment (one standard error above and below the mean percent survival, for those who might be interested).

Bar graph showing that trees might have grown slightly more when weeds were managed with herbicides. The impact of root treatment varied, depending on which weed management strategy was used.
Change in height of Christmas trees from May to October 2021. Each bar is the average of up to 28 trees (7 trees in each of 4 plots) for each combination of root treatment (color of bars) and weed management strategy (along x-axis). The lines on each bar show variability (one standard error above and below the mean value).

These Fraser fir seedlings grew between 1 and 2.5 inches during their first season. Much like the tree survival, the root treatment that produced the most growth wasn’t consistent across all weed management strategies. Results for tree trunk diameter were similar.

Bar graph showing that needle color might be slightly darker in the plots that were treated with herbicide or no weed management. The impact of root treatment varied, depending on which weed management strategy was used.
Average needle color when trees were rated in October. Lower numbers indicate darker green color. Each bar is the median value of up to 28 trees (7 trees in each of 4 plots) for each combination of root treatment (color of bars) and weed management strategy (along x-axis).

Recall that needle color was rated as 2 (darkest green), 5, 7, or 9 (most yellow or brown). So on this graph, shorter bars indicate better needle color. Also, this rating scale impacted how we summarized the data. Instead of taking the mean needle rating, we used the median. (Here’s a quick refresher on the difference.) And the graph doesn’t have those little lines to summarize the variability in each treatment. Too early to draw firm conclusions, but again, there might be some interactions between root treatment and weed management strategy.

What does it cost?

Economic risk is one of the risks we seek to reduce through IPM, so we’ve been keeping track of the costs associated with our pest management strategies. Based on the way we applied the root treatments and some local price estimates, here’s what we would have spent per acre for these treatments, assuming we planted 1,200 trees on each acre (that’s 6 ft x 6 ft spacing).

 

Fungicide Rate/A Number of applications Cost/A (Supplies) Cost/A (Labor1)
ProPhyt 11 fl oz2 1 $4 $1,037
RootShield PLUS WP 24 oz3 2 $123 $4,150
Subdue Maxx 2.5 pt3 2 $82 $2,074
Water – 1 $0 $2,075

1We assumed a labor rate of $20/hr. These costs were calculated based on the time it took us to apply the products. This includes drenching each tree by hand (RootShield PLUS WP and water) and applying Subdue Maxx (and additional water to move it into the soil) with a backpack sprayer. On a larger scale, there’s surely a more efficient way to do this.

2Seedling roots were dipped in a ProPhyt solution prior to planting. The rate on the label is 4 pt/100 gallons of water. We mixed up 2 gallons of root dip solution (containing 1.28 fl oz of ProPhyt) to treat 140 trees. If we had used a fresh 2 gallons for every set of 140 trees, we would have used 11 fl oz of ProPhyt on an acre of 1,200 trees.

3Because RootShield PLUS WP was applied as a drench to each tree and Subdue Maxx was applied as a soil-directed spray banded on either side of the row, these rates are per acre of ground to which pesticide was applied. This is less than the total space taken up by these trees in the field. Read and follow the pesticide label for instructions on calculating quantity of product needed for banded applications.

And here’s a summary of our weed management costs. You can see all the details of these costs (including labor and supplies) here.

In-row weed management Cost/A (labor and supplies)
Cultivate $248
Herbicide $86
Mulch $1,153*
Mow $293
Untreated $0

*Assumes woodchips can be obtained locally at no cost

Take home

With only one season of data, it’s too early to draw conclusions about the effectiveness (or cost effectiveness) of each treatment. So far, survival of trees treated with ProPhyt is looking very good across most weed management strategies. And we’re seeing some indication that the best (in terms of tree survival, growth, or color) root treatment to use may vary depending on what you’re doing to manage weeds.

In late October we also dug up five dead trees and sent them to the Cornell Diagnostic lab to check for Phytophthora. The trees had been dead for a while, so they were only able to test for the presence of any Phytophthora species (which could include some that don’t cause disease on Christmas trees). Four out of five trees came back positive, which makes us feel more confident that we picked a good field for this trial…if by “good” you mean one where trees will be exposed to Phytophthora. For the purposes of this project, that’s exactly what we mean.

Please let us know if you have questions and stay tuned for more updates on this project. We’ve got at least two more years to go! You can check back on this blog (subscribe so you’ll know when new posts are available!), follow Lynn Sosnoskie and Amara Dunn on Twitter or on Instagram (@specialtycropweedscience and @biocontrol.nysipm), or check out Bryan Brown’s webpage. We’ll also be hosting another field event in 2022 and hope to provide updates at future Christmas Tree Farmers Association of NY meetings.

USDA logo, accompanied by the words: National Institute of Food and Agriculture, U.S. Department of Agriculture

This work is supported by Agriculture and Food Research Initiative – Foundational and Applied Science Grant no. 2021-68008-34179/project accession no. 1025660  from the USDA National Institute of Food and Agriculture.

 

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program, with helpful input from project collaborators. All images are hers, 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, Community IPM, habitat at home, home gardens

Know your friends

Pink zinnias and yellow cosmos growing next to the brick wall of a house
Zinnias and cosmos are great food sources for all kinds of insects.

As we start August in New York, I hope that your gardens and fields are full of abundant blooms, vegetables, fruits, or all of the above. They may also be humming, buzzing, or making other noises as a result of resident insects. If you find an unfamiliar insect, you might be wondering: Is it a friend or a foe? Here are some friendly insects – natural enemies of pests – you might encounter.

Lady beetles

Red lady beetle with black spots on a green leaf
This sevenspotted lady beetle is pretty easy to recognize.

Adult lady beetles are some of the most easily recognized natural enemies. For example, most would know that this sevenspotted lady beetle is a friend. But lady beetles come in many different stripes – err – spots. Here’s another lady beetle that might not be as familiar, but is an equally good predator.

oblong pink beetle with many black spots on a yellow dandelion
You might be less familiar with the pink spotted lady beetle, but it’s a friendly insect you should get to know.

Immature lady beetles look very different from adults. But the larvae are voracious predators, and leaving the pupae undisturbed means you’ll soon have more adult lady beetles around. In addition to aphids, lady beetles will eat whiteflies, thrips, mites, and eggs of other insects.

On the left a segmented, black and orange insect on a leaf. On the right, a more round black and orange insect on a leaf.
An immature (larval) lady beetle on the left is a great predator. The pupal (resting) stage of the lady beetle on the right will soon turn into an adult.

If you’d like to identify the lady beetle species you’re finding in your garden, check out these resources from The Lost Ladybug Project.

Lacewings

Similarly, while you may be more familiar with the adult lacewings (which can be green, as well as brown), in some lacewing species it’s only the larvae with their formidable jaws that are munching on pests (generally the same ones that lady beetles eat). Adult lacewings will eat pollen and nectar (and some species also eat other insects).

On the left, a brown mottled insect with large jaws, and on the right, a green insect with lacy wings.
Larval lacewings (left; this one is magnified) look much different than adult lacewings (right).

Minute pirate bugs

Black and white insect with eyes sticking out of the side of its head.
This picture of a minute pirate bug is magnified. They are no more than a quarter of an inch long.

This friendly bug (and it is a true bug!) can be hard to spot because it’s so tiny; truly minute. If you get a chance to look at this (< ¼”) insect with a hand lens, you’ll notice a white diamond shape towards its rear, with a black diamond shape behind its head. At least that’s what the adults look like. Here’s one searching for thrips on a sign at a corn maze. The immature (or nymph) minute pirate bugs are orange and look not much like the adults. In keeping with their size, minute pirate bugs eat small pests like aphids, mites, thrips, and insect eggs. They also eat pollen and nectar, which is probably why I often bring a few inside with me when I cut flowers from my garden. Those same mouthparts that are great at eating pests can also give you a small (but startling) pinch. But it doesn’t hurt much, and if you leave them undisturbed, both you and the pirate bugs will be happier.

Hover flies

Four pictures of hover flies. Some are smaller with narrow bodies, while others are larger with rounder bodies. One is even a little fuzzy.
Adult hover flies come in different sizes, shapes, and stripe patterns, but they are great pollinators and good friends to have in the garden or field.

Sometimes hover flies (also called syrphid flies) are incorrectly called sweat bees. Sweat bees are true bees. While many hover flies are black and yellow striped, and some look quite a lot like bees, they are flies. True to their name, hover flies are often spotted hovering around flowers. Here are two tips for distinguishing hover flies from bees:

  • Hover flies have big eyes that take up most of their head; bee eyes are usually smaller and oval-shaped
  • Hover flies have only two wings; bees have four

Immature (larval) hover flies are the ones that are eating pests on your plants. They look like small worms, and may come in slightly different sizes or shapes. But they love to eat aphids, whiteflies, and scales.

Translucent green maggot with brown stripe down the middle feeding on black aphids on a plant.
I’m not 100% sure if this is a hover fly larva, or another predatory fly larva. But this will give you some idea of what you’re looking for.

(Predatory) stink bugs

brown stink bug eating a black, yellow, and white striped caterpillar
Carnivorous (as opposed to plant-eating) stink bugs are generalist predators, so you may sometimes find them eating other beneficial insects.

None of us are happy to find stink bugs (usually brown marmorated stink bugs, to be specific) invading our homes, but there are many more stink bug species, and some of them are excellent predators. I know, the one above happens to be eating a monarch caterpillar, but they will eat pest caterpillars and other insects, too. The advantage of generalist predators is that they will eat all kinds of pests. The disadvantage is that they may also eat some insects that aren’t pests. This is just part of a balanced ecosystem in your garden or field.

It can be difficult to distinguish a predatory stink bug from a pest stink bug, without looking closely at its proboscis (straw-like mouthparts used for sucking either plant or bug juices), but Virginia Cooperative Extension has a nice field guide available here, which can help. Or you could spend some time observing the stink bug to see if it’s eating a plant or another insect.

Spiders

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 of fields.

Spiders (examples on the left and middle in the above picture) and harvestmen (example on the right) may make some people feel uncomfortable, but both are generalist predators, and therefore good to have around. The spiders you are likely to find in New York are nearly all non-venomous, so welcome them without fear. More info about common spiders of NY can be found here.

Wasps

On the left, a black wasp with yellow stripes on a red flower bud, and on the right, a black and orange wasp on pink milkweed flowers
Just two of many wasps you might find visiting flowers in your garden or field.

If you are growing a diversity of flowers that produce lots of pollen and nectar, you may also see a diversity of wasp visitors. Most are unlikely to sting you, and even wasps like yellow jackets or hornets that may sting you are likely also looking for caterpillars and other insects to eat. Many wasps (including tiny ones you won’t notice and larger ones that you will) can also kill pests by laying their eggs in or on them. These are called parasitoid wasps. So if wasps aren’t hurting anyone, leave them alone. Of course, if stinging wasps are building a nest on or near a structure where they are likely to be disturbed by people, action may be required. Learn how to use IPM for stinging wasps here.

Bright green caterpillar with a horn at its rear end, with about a dozen white capsules (wasp pupae) attached to its back.
This hornworm was parasitized by a wasp, and its tomato-munching days are numbered. New wasps will emerge from the white sacks on its back.

Other flies

Large fly with thick thorax, long abdomen, and bristles on legs and around mouth
Robber flies may not look very pretty, but they are good predators to have around.

Besides hover flies, there are a whole lot more flies visiting gardens and fields, and many will either eat or parasitize pests. The robber fly pictured above is especially large and is a great predator. Of course, there are plenty of flies you don’t want around. For more info on IPM for flies around your home, you can look here. You can find resources for managing livestock flies here.

And there’s more!

This is by no means an exhaustive list of insect natural enemies. For example, there are a variety of other true bugs, including big-eyed bugs, damsel bugs, assassin bugs, and ambush bugs that will eat pests in your garden or field. The ambush bugs are the easiest to recognize.

Brown and cream colored bug perched on the cream and pink speckled petals of a zinnia flower
This ambush bug isn’t too hard for you or I to spot on this zinnia. Hopefully its prey won’t see it so easily.

And, this list  doesn’t touch on most of the ground-dwelling natural enemies (although some spiders are predominantly found on the ground. I’ll cover those in another post.

 

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, Christmas tree establishment IPM, IPM, ornamentals

Introducing a new Christmas tree project

Field with mostly bare ground and small Christmas tree seedlings, each marked by a flag. In the background are some trees and a blue sky with puffy clouds.
We planted a new field of Christmas trees this spring!

If you’ve been following this blog for a bit, you might recall that the beneficial insect habitat plots I’ve been helping to establish and monitor with my colleagues Betsy Lamb and Brian Eshenaur are located on the edges of a field of Christmas trees. Once the trees get a bit bigger, we’ll be able to start assessing whether trees closer to these wildflowers have fewer pests or not.

New in 2021, I’m collaborating with Bryan Brown, Brian Eshenaur, Betsy Lamb, and Lynn Sosnoskie on a three-year project funded by the USDA to look at IPM when you’re establishing a new field of Christmas trees. An important part of IPM is the integration of multiple strategies when managing pests. So in this project we’re looking at some tools for managing both weeds and root diseases (specifically Phytophthora).

Weeds

Our weed management strategies include:

  • Mulching with approximately 3 inches of chipped shrub willow
  • Cultivating three times early in the season using a KULT Kress Argus Toolbar with rear side-shift adjustment pulled by a tractor
  • Mowing grass seeded around the trees
  • Conventional herbicides (oxyfluorfen and pendimethalin applied shortly after planting, with the possibility of additional applications depending on the length of the residual control) as a control treatment
  • No weed management at all (another control treatment)

We planted 560 Fraser firs in 20 rows on May 19th, and four of these rows will be receiving each of these different weed management treatments. So far, we’ve spread mulch…

Four people spreading mulch around small Christmas tree seedlings in a field with rakes or by hand.
Mulch was dumped in small piles along the row of trees, and we raked it in to place. Photo taken by Lynn Sosnoskie.

…and applied herbicides.

Woman in Tyvek suit with backpack sprayer applying herbicides to rows of Christmas tree seedlings. Seedlings receiving herbicide have plastic cylinders around them to protect them.
Since a few of the trees were getting close to budbreak, we shielded them when applying the herbicide.

Lynn and her team collected soil from the field to assess which weed seeds are currently present in the seedbank. They will continue to evaluate the weed seedbank yearly to determine whether different weed management programs result in different weed seeds in the seedbank. Bryan, Lynn, and technicians working for them will also be assessing the success of each weed control strategy throughout the season (weed density and biomass).

Disease

Within each row, plots of seven trees have been assigned to one of four different treatments for root disease control. The biocontrol piece of this project is the root disease management tools. The biofungicide RootShield PLUS WP contains two different species of the fungus Trichoderma. These fungi may protect the trees by:

  • Inducing resistance – turning on the plants defense mechanisms ahead of pathogen attack
  • Exclusion – growing on the roots so there’s no space for the pathogen to grow
  • “Eating” the pathogen – Trichoderma is a fungus that parasitizes other fungi (and water molds)
  • Poisoning the pathogen – Trichoderma produces antimicrobial compounds
  • Promoting plant growth – Stronger, healthier trees are more likely to survive pathogen attack (and probably be more resilient to water stress).

A study done in Oregon on Douglas fir found that Trichoderma species might help improve survival of trees in pots when they are being attacked by the water mold Pythium. So we’re curious if we can document similar results in the field. We applied RootShield PLUS as a soil drench immediately after transplanting, and will repeat the application 6-8 weeks later.

There’s also been some work done by Richard Cowles in Connecticut suggesting that ProPhyt could improve the color of Fraser firs when they are planted in a field known to have Phytophthora. The active ingredient in ProPhyt is potassium phosphite (equivalent to phosphorous acid), so this product is also classified as a biopesticide by the EPA. I think of it as not really a biological control, since it neither contains a (current or formerly) living organism, nor was made by a living organism. We applied ProPhyt as a root dip immediately before planting. It works by inducing plant resistance, and also inhibiting (“poisoning”) water molds like Phytophthora.

The other two root disease treatments are controls: Subdue Maxx (active ingredient mefenoxam) and just water. Subdue Maxx was applied as a shielded, soil-directed spray the day after we transplanted the trees. All the trees were watered in right after planting because we planted a bit late in the season and it was a pretty warm day. The label calls for a second application in the fall.

So far, we’ve collected data on the initial height, stem diameter (4 inches above the soil) and needle color of every tree in the field. We’ll do this again in the fall to assess tree growth over this first season, and tree health (needle color). We will also record how many trees in each treatment survive. Bi-weekly weed surveys have also been initiated. Bryan has started cultivating the trees in that weed control treatment.

Video of Christmas tree cultivation

For updates on this project, you can check back on this blog (subscribe so you’ll know when new posts are available), follow Lynn and Amara on Twitter or on Instagram (@specialtycropweedscience and @biocontrol.nysipm), or listen to Bryan’s podcast. We’ll also be hosting events at the field (Geneva, NY) in this and subsequent years (put August 19th on your calendars, and stay tuned for more details), and hope to provide updates at future Christmas Tree Farmers Association of NY meetings.

USDA logo, accompanied by the words: National Institute of Food and Agriculture, U.S. Department of AgricultureThis work is supported by Agriculture and Food Research Initiative – Foundational and Applied Science Grant no. 2021-68008-34179/project accession no. 1025660  from the USDA National Institute of Food and Agriculture.

 

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

agriculture, habitat plots, IPM, ornamentals

Creating Habitat for Beneficial Insects: 2020 Growing Season Update

panoramic view of a field with some pink and purple wildflowers blooming in the foreground and rows of small Christmas trees in the background
Trips to our beneficial insect habitat and Christmas tree research plots this year were very solitary, but it was good to get outside.

As many people did, we had to change our plans for this project in response to COVID-19. The biggest change was that we didn’t collect any insects this year. If you follow me on Twitter or Instagram, you saw some pictures of different insects I spotted while visiting these plots this summer. Here are a few highlights:

Composite of images showing a blue dragonfly, several bees (brown and green), a large black and yellow spider, a red ladybug with black spots, a black and yellow striped hover fly, and an orange and black ladybug larva.
Just a few of the cool insects (and one arachnid) I was able to photograph during my weekly visits to the habitat plots.

The Christmas trees are still growing, and Brian Eshenaur and I made sure that the weeds didn’t take over. One Christmas tree grower suggested that they might need some trimming next year. I’m adding “Christmas tree shearing” to the list of new things I will try (learn?) in 2021.

Several smaller Christmas trees growing in a field
Slowly but steadily, the Christmas trees adjacent to our beneficial insect habitat plots are growing!

From May through mid-October, I visited our beneficial insect habitat plots once a week to take pictures and document what was blooming. Brian and I also mowed plots that were direct seeded in fall 2018 twice (May and June). Those of you reading this from NY know how dry much of our summer was, and there really wasn’t a need for more frequent mowing. We decided not to mow Treatment C, which had been direct seeded in spring of 2018. The standard recommendation for establishing perennial wildflowers from seed is to mow for the first two growing seasons, and in the third year to start scaling back on the mowing. Since this was the third season for these spring-seeded plots, we skipped the mowing. I’m not sure we made the right decision for our plots.

Plot of mostly grass and small white asters with a few blackeyed susans and purple coneflowers mixed in.
One plot that was direct seeded in the spring of 2018 and not mowed this year. There were a lot of weeds (some blooming) in addition to some of the species we seeded.

Some of the perennials we seeded bloomed, but mostly these plots were over-run by grass and some weedy asters. It could be that the wildflower establishment was poor. Spring is not the recommended time for planting perennial wildflower seeds. Or it could be that these plots needed to be mowed at least once this season. Since 2021 will be the third year for the fall-seeded plots, I’m wondering about reducing the mowing in these plots, instead of stopping “cold turkey”.

In the meantime, the fall-seeded Treatments F and G (mowed twice in 2020) are developing nicely! Even when there weren’t many flowers, I could recognize lots of wildflower seedlings.

Picture of mixed species plants, with only two yellow flowers. Purple circles and labels identify butterfly milkweed, blackeyed susan, wild bergamot, smooth blue aster, purple coneflower, and coreopsis seedlings.
At first glance, this might look like a patch of weeds, but I’ve learned to spot some of the seedling perennial wildflowers direct seeded in fall 2018.

In July and August, there were abundant blackeyed susan blossoms, and in September and October all four aster species bloomed.

Somewhat weedy plot with lots of blackeyed susan blooms (yellow with dark brown centers); some Christmas trees, grass, and blue sky with puffy clouds are in the background
The fall-seeded habitat plots don’t look manicured like the plots that were transplanted in spring and mulched, but there were a lot of blackeyed susans blooming in mid to late summer this year!
Mixture of seedlings, some with daisy-shaped flowers in various shades of purple
Direct seeded plots contained New England asters (darker purple flowers), zigzag asters (pale flowers, stems grow in zigzag pattern), smooth blue asters (pale purple flowers, smooth leaves and stems), and aromatic asters (more compact growth habit, light purple flowers).

This year, I kept notes not only on what was blooming each week, but on whether blossoms had just started to open (E = early bloom), were fully open (P = peak bloom), or were fading (F = fading bloom). Because there were 12 plots for each transplanted or direct seeded species, if the plots were evenly split between early and peak (E/P) or peak and fading (P/F), I included these two intermediate categories. You can see a color version of the following tables here. The colors give a nice visual of the progression of blooms over the season (including some weeks when there was a bit of a lull in blooms).

E early bloom
E/P evenly mixed early & peak bloom in different plots
P peak bloom
P/F evenly mixed peak & fading bloom in different plots
F fading blooms

When transplanted wildflowers bloomed in 2020

May Jun Jul Aug Sep Oct
5 12 21 27 1 9 16 23 30 6 14 21 28 6 12 17 26 1 8 15 22 28 6 14
Golden alexanders E P P P F F
Ohio spiderwort E E E P P P F F F F F F F F
Catmint E P P P/F F F F F F F F F F F F F F F F F
Lanceleaf coreopsis E P F F F
Blue false indigo E P
Tall white beard tongue E P F F F F
Common milkweed E F
Purple coneflower E E P P P F F F F F F F
Wild bergamot E P/F F F F F F
Anise hyssop E P P F F F F F
Boneset E P P F F F F
NY ironweed E E E P P P P F F
Orange coneflower E E P P P P P/F F F F F
New England aster E E E E P P P F
Showy goldenrod E P P F F

When direct seeded wildflowers bloomed in 2020

May Jun Jul Aug Sep Oct
5 12 21 27 1 9 16 23 30 6 14 21 28 6 12 17 26 1 8 15 22 28 6 14
Golden alexanders E P P/F
Hairy beard tongue E E
Lanceleaf coreopsis E P/F F F F F F E P F F F F F F
Tall white beard tongue E
Blackeyed susan E E P P P P P P P/F P/F F F F F F F
Purple coneflower E E P P P P F F F F F F E/P
Wild bergamot E F F
Butterfly milkweed P F E
Orange coneflower E P P P/F F F
Smooth blue aster E E P P P P
Gray goldenrod E E E/P P F F
New England aster E E P P P
Zigzag aster E E P P P
Aromatic aster E/P E/P P
Yellow false indigo
Partridge pea
Marsh blazing star
Narrowleaf mountainmint
Wild senna
Maryland senna
Early goldenrod
Ohio spiderwort

 

Common name Scientific name
Anise hyssop Agastache foeniculum
Aromatic aster Symphyotrichum oblongifolius
Blackeyed susan Rudbeckia hirta
Blue false indigo Baptisia australis
Boneset Eupatorium perfoliatum
Butterfly milkweed Asclepias tuberosa
Catmint Nepeta faassinii
Common milkweed Asclepias syriaca
Early goldenrod Solidago juncea
Golden alexanders Zizia aurea
Gray goldenrod Solidago nemoralis
Hairy beard tongue Penstemon hirsutus
Lanceleaf coreopsis Coreopsis lanceolata
Marsh blazing star Liatris spicata
Maryland senna Senna marilandica
Narrowleaf mountainmint Pycnanthemum tenuifolium
New England aster Symphyotrichum novae-angliae
NY ironweed Vernonia noveboracensis
Ohio spiderwort Tradescantia ohiensis
Orange coneflower Rudbeckia fulgida va. Fulgida
Partridge pea Chamaecrista fasciculata
Purple coneflower Echinacea purpurea
Showy goldenrod Solidago speciosa
Smooth blue aster Symphyotrichum laeve
Tall white beard tongue Penstemon digitalis
Wild bergamot Monarda fistulosa
Wild senna Senna hebecarpa
Yellow false indigo Baptisia tinctoria
Zigzag aster Symphyotrichum prenanthoides

From the second or third week of May through the second week of October, there was always something blooming in these plots, whether they were transplanted or direct seeded. You can also see that a fair number of species in the seeded plots did not bloom this year. Hopefully next year.

In the meantime, I’ll be making plans for the 2021 growing season, which will hopefully include a return to insect sampling. Stay well and stay safe!

 

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:

  • 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
  • The Towards Sustainability Foundation
agriculture, Community IPM, home gardens, IPM

New biocontrol solution coming to invasive weeds near you? Probably not yet.

Large clump of knotweed with large heart-shaped leaves and clusters of small white flowers
Japanese knotweed is very invasive. Photo credit: Amara Dunn, NYSIPM

At a previous residence, Japanese knotweed was the bane of my backyard gardening endeavors. Masses of these invasive plants can easily stifle native or non-invasive plants. The roots grow deep and even small pieces left in the ground can re-grow new plants. I used frequent hand-pulling and digging in an attempt to keep it in check, and I knew that if I stopped it would just grow back. For more information on this invasive weed, refer to this excellent fact sheet.

Large leaves with smooth edges attached alternately along a red stem.
Close-up of Japanese knotweed leaves. Photo credit: John Cardina, The Ohio State University, Bugwood.org

I have read that you can cook and eat it, but I haven’t tried. And no matter how delicious it might be, it would still be horribly invasive. While bees will visit the flowers late in the summer, there are better ways to feed the bees.

small white flowers of Japanese knotweed being visited by a wasp
Japanese knotweed can provide food for pollinators, like this wasp.

You may have heard that Cornell researchers led by Dr. Bernd Blossey released the Knotweed Psyllid (Aphalara itadori) in June 2020 in Tioga and Broome counties as a potential biocontrol agent for this invasive weed. This release came only after thorough testing and permission from the U.S. Department of Agriculture, since this insect is native to Japan. You can learn more about the process of using classical biocontrol to manage weeds here. Be assured, many precautions are taken before non-native species are intentionally released in the U.S.

Tiny brown insects perched on a large smooth leaf and a small folded up leaf
Tiny psyllids released in Tioga County in an attempt to control invasive Japanese knotweed. Photo credit: Bernd Blossey, Cornell University

Unfortunately, attempts to establish this insect in both the United Kingdom and Canada have not been successful. Preliminary results from the NY releases suggest that this psyllid will not be the biocontrol solution we need for Japanese knotweed. Most of the insects that were released do not seem to have survived and even when the insects were protected in cages put around the knotweed plants, they didn’t reduce the growth of the plants.

It seems that if we are going to solve this weed problem with biocontrol, we will need to find other insects from the native range of Japanese knotweed. Assessing these insects prior to release in the U.S. will be a lengthy process, so in the meantime keep using other IPM tools for this invasive weed.

If you’d like to learn more about this project, the New York Invasive Species Research Institute is hosting a webinar on September 30, 2020 at 11:00 AM.

 

This post was written by Amara Dunn (NYSIPM) and Dr. Bernd Blossey (Cornell Department of Natural Resources).