Close to thirty years ago, Dr. Tony Shelton (now Professor Emeritus, Department of Entomology, Cornell University) launched a website called Biological Control: A Guide to Natural Enemies in North America. It included great information about the biology of biocontrol, individual articles about species or groups of biocontrol agents, and much more. As Dr. Shelton approached retirement, he reached out to me and NYSIPM and we agreed to take over managing and updating the site. Since then, I’ve been working on migrating content, updating it as I go.
Biocontrol agents are organisms that do biocontrol (control pests). Profiles of 42 biocontrol agents are now available on NYSIPM’s website.
As I planned the migration of the articles about individual biocontrol agents from Dr. Shelton’s website, I knew that I wanted to make it easy for readers to quickly find answers to common questions (Does it work? What pests are targeted?), break up the text into smaller sections, and retain the valuable (and more technical) information that made Dr. Shelton’s website valuable to scientists, too. I am incredibly grateful to all the authors who revised or wrote brand new content that fulfills these goals. The first 42 biocontrol agent profiles are now up on the website! Currently, you can browse them based on either the type of pest they target (insects or weeds, for now), or you can browse by the type of biocontrol agent. We’re still working on ways to expand how you can search for biocontrol agents of interest.
Each new biocontrol agent profile has updated pictures and summarizes information in smaller blocks of text.
I’m excited about:
New and more pictures
Compatibility with mobile devices and more accessible
Organized to provide straightforward answers to frequently asked questions
Consistent format so you can look for the same information in the same part of each profile
So, check them out and let me know what you think! There are still many more articles to revise and migrate, and new biocontrol agents to add. If you are someone with expertise in a biocontrol agent and would like to revise or write one of these profiles, please get in touch with me!
This work is supported by NYS Departments of Environmental Conservation and Agriculture and Markets. It was also funded in part by the Northeastern IPM Center through Grant #2018-70006-28882 from the National Institute of Food and Agriculture, Crop Protection and Pest Management, Regional Coordination Program.
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.
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 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.
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
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.
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.
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:
Pesticide compatibility checkers from two companies that sell arthropod biocontrol agents: Koppert and Biobest
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?
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
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).
I don’t know about you, but I can’t wait to get some seeds into potting mix and some plans for my garden on paper! While you’re planning your garden, why not join NYS IPM for our virtual conference? This year we’re talking about “Biological Control: Partners in the Garden” and we’ve got a great line up of speakers!
Carol Glenister form IPM Labs talks about looking for signs that natural enemies (biocontrol agents) are already at work in your garden
John Losey from Cornell University talks about everyone’s favorite biocontrol agent – ladybugs
NYS IPM staff will talk about biocontrol for weeds (is there any?), conserving our biocontrol partners in the garden, and more!
Mary Centrella from the Cornell Pesticide Safety Education Program will talk about proper use of pesticides to protect garden partners
Kyle Wickings will talk about using tiny worms (entomopathogenic nematodes) to deal with lawn grubs
The conference will take place the mornings of Tuesday and Wednesday March 15 and 16, with a special interactive workshop being offered (by yours truly) on Tuesday afternoon (1-3 PM). You’ll receive some pre-workshop materials to help you get the most out of the workshop, and leave with a plan to plant flowers that will feed and support natural enemies in your garden.
The conference is just a little more than a week away, so register soon! Pay what you can afford, and please reach out if the registration fee is a barrier. NYS IPM is committed to making this conference (and all of our resources) accessible.
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
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.
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.
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.
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).
Larval lacewings (left; this one is magnified) look much different than adult lacewings (right).
Minute pirate bugs
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
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.
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
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
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
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.
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
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.
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
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:
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.
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
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.
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 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 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.
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.
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), Heterorhabditisbacteriophora, Steinernema, Steinernemafeltiae, Steinernemacarpocapsae
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
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)
many insects (target pest depends on fungal species and strain)
Paecilomyces (=Isaria) fumosoroseus, Beauveriabassiana, Metarhiziumanisopliae (= 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
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:
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.
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.
A tiny wasp lays its eggs in the larvae of the invasive lily leaf beetle. Releasing these wasps in the northeastern U.S. is a form of classical biocontrol. Photo credit: Dan Gilrein
Last week, some colleagues told me about a cool online database that will help you learn more about how classical biocontrol is helping us fight invasive insects.
Classical biocontrol means introducing a natural enemy of a pest to help manage that pest. The natural enemy establishes a population where you have released it (and maybe even spreads), so that you don’t need to repeatedly release more natural enemies. It is a strategy that can be especially useful against invasive pests.
One thing that makes a pest invasive is the fact that when it arrives in a new place (for example, on a new continent), native organisms don’t eat it because they have not evolved with this new pest as a food source. Sometimes scientists can search the geographic area from which the invasive pest came and find a natural enemy of that pest. Many tests are done over a long period of time in order to assess potential unintended consequences of introducing this natural enemy to a new place. For example, scientists determine whether the new natural enemy is likely to also impact populations of native organisms (especially those that are not pests). Only after extensive study will this new natural enemy be released to help reduce populations of the invasive pest.
When done carefully, classical biocontrol can be a lower-risk solution to managing invasive pests compared to chemical pest management. It is also a long-term solution. The new natural enemy reproduces in its new geographic range and brings the invasive pest population into balance. The invasive species won’t be eliminated, but it will likely do less damage.
A new database from the University of Massachusetts lets you learn more about insects that have been introduced to North America to control invasive insect pests as classical biological control agents. You can Search the Catalog by the scientific name of the target pest, the scientific name of the natural enemy, information about where and when the natural enemy was first released, or other criteria.
The invasive hemlock woolly adelgid on a hemlock branch. Several different classical biocontrol agents have been released in the U.S. to manage this invasive pest. Photo credit: Amara Dunn
You will need to know the scientific name of the pest or natural enemy you are interested in, but a quick Google search can help you with that. For example, Adelges tsugae is the hemlock woolly adelgid, which you may have heard about. If not, you can learn more here. Laricobius nigrinus was released to help manage hemlock woolly adelgid. Other examples include Agrilus planipennis (emerald ash borer) and Lilioceris lilii (lily leaf beetle). NYS IPM is involved in a project to use classical biocontrol to manage this last pest in NY.
As the days start to get shorter and cooler, you might find yourself spending more time indoors. And if that’s the case, why not spend some time learning more about how classical biocontrol is helping to manage pests in the landscapes around you?
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 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.
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).
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.
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).
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).
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.
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).
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.
