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.
Many people understandably think about spring as the season for seeding. When it comes to vegetables and flowers that grow as annuals in New York State (and other places with similar climates), you’re generally right. (Of course there are exceptions to every rule.) But many perennial wildflower species have adapted to produce seeds that won’t germinate immediately. Certain conditions have to prepare and signal these seeds to germinate. They require stratification prior to germination. If you are trying to germinate these seeds, you can stratify them yourself, or you can let winter cycles of freezing and thawing and fluctuating soil moisture do the work for you by planting perennial wildflower seeds in the fall.
How to sow perennial wildflower seeds in the fall
If you want to try this yourself, now (September) is a good time to prepare soil in a spot where there aren’t a lot of other plants growing already. If you’re trying to convert lawn or a weedy spot into a wildflower planting, it will be easier if you’ve spent at least one growing season managing weeds. But, if the summer flew by and you are just digging up a fresh spot now, don’t despair. You may just have more weeds to deal with in the spring. (More on weeds later!)
Once your soil is ready, put a note on your calendar to remind yourself to plant your seeds a bit later. In central NY, mid-October through December is a good time to sow perennial seeds outside. You want to wait until it’s too cool for the seeds to germinate this fall. Perennial wildflower seeds will germinate and the young plants will establish best if you invest some time in creating a nice seed bed for them first.
Ideally, select a spot where the soil is mostly bare. Pull or dig out remaining weeds. Depending on when you want to plant seeds, you could use cardboard or a tarp to help you kill existing vegetation first. You could also use an herbicide, but make sure you select a product that is labeled as an herbicide. Do NOT mix your own herbicide from ingredients around your home. Always read and follow the label when applying any pesticide, including herbicides.
Loosen the soil. You can use a shovel, rake, digging fork, or other tool, depending on the size of your planting area. You want the soil to be nice and crumbly and have “nooks” for the seeds to fall in to.
Perennial wildflower seeds benefit from soil preparation. If possible, pick a spot where few weeds or other vegetation are growing. Remove whatever vegetation is there to leave bare soil.
If you prepare your soil now (late September), make sure you check it just before you are ready to plant your seeds. Repeat step 2 if necessary to provide your seeds with a nice seed bed. And remove any weeds that may have sprouted!
Between mid-October and December (in central NY), scatter the seed on the soil. If you are using a mixture of wildflower seeds, follow the instructions that came with them to spread the seeds at the correct density. If you are just planting a few seeds, you might sprinkle them in rows so they will be easier for you to spot when they start germinating.
Gently mix the seeds into the soil, but no deeper than ¼ of an inch. Generally, the smaller the seed, the shallower it should be planted. If you have a larger area, a rake is a good tool to use. If you are planting a few seeds per species, you could use a hand rake or even a fork from the kitchen. Get creative!
Press the seeds into the soil. You want the seeds to be pressed tightly against the surrounding soil. You can use your hands, feet, or a roller depending on the area you are planting.
Label your seeds. Make sure you know where to look for your seedlings in the spring! Add some markers to remind you where to look.
You can use your feet to stomp your seeds into the soil ensuring good seed to soil contact.
In Spring 2025 I will share some tips and pictures to help you recognize your seedlings as they start to germinate (amongst the inevitable weeds that will be there, too).
A few words on weeds
Unless you have spent literally years depleting the soil of weed seeds, it is inevitable that there will be some weeds germinating with your perennial wildflower seeds in the spring. If you are planting a larger area with a seed mix and planning to manage (annual) weeds with mowing, this is not such a problem. You will be mowing the area for the first few years to prevent annual weeds from producing seed and effectively reducing the weed seed bank. Like other perennials, your wildflowers will survive the mowing just fine.
If you are planting just a few seeds of each species and carefully marking their location, this will help you know where to look for germinating perennials in the spring. Planting in rows (or some other pattern) may also help, but you’ll need to be careful not to disrupt your pattern when you gently work the seeds into the top ¼ inch of soil.
To get around some of the above weed challenges, I’m told that the “Winter Sowing Method” developed by Trudi Davidoff works well for native perennial wildflowers. But you should probably delay planting the seeds until November or December if you’re using this method. Essentially, you create a mini greenhouse using potting mix in a repurposed transparent plastic container (like a milk jug) with drainage holes. Leaving the container outside and exposed to rain allows the seeds to experience temperature and moisture fluctuations. Since your seeds are planted in potting mix in a discrete container, you won’t be fighting weed seeds and you’ll know where to look for your seedlings. An episode of the Growing Greener podcast describes how this method is used for native perennials.
Check out my full instructions for creating habitat for beneficial insects to learn more about other methods for establishing these plants. And remember that growing perennial wildflowers from seed will take some time. Be patient!
It will be a few years before your wildflowers look like this, but they are worth the wait!
Native plants provide many ecological benefits and make the shores of Seneca Lake even more beautiful.
Native plants are a key component of the green infrastructure the City of Geneva, NY has installed throughout downtown. In addition, numerous volunteers have dedicated countless hours to planting and maintaining native plants along Seneca Lake. The goal is to support native insects, wildlife, and the rest of the ecosystem, reduce water and maintenance needs, increase the ecological resilience of the City, and protect beautiful Seneca Lake.
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.
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)
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.
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.
Perennial wildflowers add both beauty and food for beneficial insects to your yard.
Why grow perennial wildflowers?
Native wildflowers feed and shelter beneficial insects that pollinate our plants and help us control pests. Beneficial insects include a diverse collection of pollinators — not just honey bees — as well as natural enemies (flies, wasps, beetles, bugs and other insects that kill pests). While not technically insects, spiders and predatory mites also serve as natural enemies of pests. Cooperating with insect natural enemies for pest control helps us reduce damage from pests while reducing risks to the environment and people from other pest management strategies like pesticides.
The pollen and nectar produced by these native flowers – and many non-native flowers – either directly feed these friendly insects, or feed other insects that are prey for natural enemies. The leaves and stems also provide shelter for beneficial insects year-round. While we’re focusing on flowers today, many grasses also provide this shelter. Beyond all the ecological benefits, native wildflowers are beautiful!
Preparing perennial seeds to germinate
Growing perennial flowers from seed does take longer, but it can be fun and rewarding!
In this part of the world (now known as upstate New York), seeds from native perennial wildflowers that mature in summer and fall experience a lot of “weathering” between maturation and germination the following spring. This includes cycles of freezing and thawing temperatures as well as varying levels of moisture during the winter. They may even pass through the digestive system of animals. This is why planting perennial wildflower seed in the fall is a great option. You are allowing nature to do the work of preparing the seeds for germination in the spring. If you harvest seeds of native perennial wildflowers and want to start them in the spring with other seeds, you will need to do this work yourself.
Some seeds have very hard seed coats that need to be broken by physical force (for example scratching with sandpaper, a file, or a knife), heat (for example, submerging in boiling water), cold (for example, freezing), or chemicals (like a strong acid). This is called seed scarification. Seeds that require scarification – and those that don’t – may also require stratification, which signals to the seeds that they can “wake up” (called breaking dormancy) and start germinating. Seed stratification generally requires exposing the seeds to the right level of moisture and the right temperature for the right length of time. Some examples include:
Hot water soak – Pour hot water over seeds and allow them to soak overnight or for 24 hours
Cold moist stratification – Mix seeds with sterile sand, vermiculite, or another substance that won’t hold too much moisture. You could also place seeds between layers of a damp paper towel or coffee filter. Make sure that whatever medium you use is only damp and not too wet. Put the mixture in a plastic bag or closed container in your refrigerator for the required amount of time.
If you buy perennial wildflower seeds, they may have already been stratified. Follow the instructions that come with your seed or reach out to the seller for more information.
One way to stratify seeds (prepare them for germination) is to place them in moist potting mix in the refrigerator for several weeks to several months.
Species-specific instructions
Examples of perennial wildflower seeds that benefit from scarification and/or stratification follow. After these seeds are scarified and/or stratified, germination may be improved by putting them in a warm place (but not for all species). Remember that you can always sprinkle seeds on well-prepared, weed-free soil outside in the fall and let the winter do the work for you! Also, your experience germinating these seeds may differ from the recommendations below. There is so much beautiful diversity in these perennial wildflowers!
Blue false indigo (Baptisia australis) – First scarify the seeds. Gently rub them between medium-grit sandpaper to scratch the seed coat. Then use the cold moist stratification method, leaving them in the refrigerator for about 10 days.
New York Ironweed (Vernonia noveboracensis) – Use cold moist stratification, keeping seeds chilled for 60 days.
Asters (Symphyotrichum spp.) – If you look up how to seed asters, you’ll see different instructions for different species, including seeding them in the spring without stratification and using a 60-day cold stratification period. Amara tried germinating Symphyotrichum oblongifolium (aromatic aster) seed and had better luck with cold moist stratification than seeding without stratification. You might see different results with different species.
Milkweed (Asclepias spp.) – Store (well-dried!) seeds in the freezer for several months (e.g., from the time you harvest them in the fall, until you are ready to start them in the spring). Learn more from Petra at Fruition Seeds.
Coreopsis (Coreopsis spp.) – Note that some coreopsis species are annuals in upstate NY. Perennial species will likely germinate best with cold moist stratification (30-60 days, depending on species).
Echinacea (Echinacea purpurea) – These seeds will likely germinate just fine if you plant them in moist soil and provide warmth (e.g., a heat mat) just as you would annual seeds.
Blazing star (Liatris spicata) – Moist stratify for 60 days before planting seeds.
Beard tongue (Penstemon spp.) – Cold stratify for 30-60 days before planting seeds. Some species may require light for germination. Cover seed of these species with only a very thin layer of potting mix (if any) and provide light when germinating.
Mountain mints (Pycnanthemum spp.) – You should be able to germinate seeds without stratification, but they will likely germinate better with light. Cover seed with only a very thin layer of potting mix (if any) and provide light when germinating.
Rudbeckia (Rudbeckia spp.) – Different species of Rudbeckia may require different stratification (or none) for seed to germinate. For many species, cold moist stratification for at least 30 days is recommended.
Goldenrod (Solidago spp.) – There are many species. Most will likely germinate best if seed is moist stratified for 60 days, and then receive light after seeding. Cover seed with only a very thin layer of potting mix (if any) and provide light when germinating.
Spiderwort (Tradescantia ohiensis) – For this species, you are better off direct-seeding in the fall. The recommended cold moist stratification period is 120 days, and these seeds will germinate better in cool soil.
Golden alexanders (Zizia aurea) – You may have better luck sowing these seeds outside in the fall than trying to start them inside in the spring. Their leaves are fairly distinctive (like celery) so seedlings are easier to spot outdoors. If you do want to try starting them indoors, use a 60-day cold moist stratification.
For some of the species that require longer stratification, you may be worried that you’re running out of time this spring. Remember that even after you have prepared your seeds to germinate, they will likely need around 6 weeks to germinate and grow big enough to consider transplanting outdoors. Don’t despair! Fall is a great time to transplant perennial wildflowers. And perhaps your heat mats and grow lights (or other seed germination spot) are otherwise occupied starting annual vegetable and herb transplants this spring. If you start stratifying seeds in early May, even those that require 60 days in the fridge will be ready for germination in early July. Then your seedlings will have plenty of time to grow big and strong before fall transplanting. Just be sure to keep them watered.
Echinacea and goldenrod are just two species of native perennial wildflowers that feed beneficial insects.
For the past six years, we’ve been cultivating perennial grasses and wildflowers that feed and support beneficial insects. All of these plants came from seeds—whether sown by us or by others—and we’ll focus this year’s annual open house on these wonderful seeds.
Come join folks from New York State Integrated Pest Management, and Petra Page-Mann from Fruition Seeds to talk about how we harvest, clean, store, and germinate seeds of perennial wildflowers that support beneficial insects. Stop by our open house between 3:30 and 6:30 p.m on Thursday, August 17. We’ll offer guided explorations of our established plots of perennial wildflowers and grasses at 3:45, 4:45, and 5:45 p.m. You are also welcome to explore the field on your own, or browse our interactive resources on display. There will be a few hard copies of resources available at the event, and we’ll continue to add digital resources to this folder up to and following the event. Everyone will go home with seeds of native perennial plants that support beneficial insects.
No registration needed for this free event. Find all the details at our event page. When you arrive at the entrance to the farm, look for signs with the pink echinacea flower and the Christmas tree on them, and follow the signs to our field.
Follow these signs to find our field!
Funds for this project were provided by NYS Dept of Ag and Markets and the USDA National Institute of Food and Ag.
Are you using copper to protect your tomatoes from bacterial diseases? Research from Cornell suggests that you could replace some of those copper applications with a biopesticide.
On tomatoes bacterial speck and spot both look like small black spots which may develop yellow halos around them as the lesions age.
Preventing bacterial diseases on your tomatoes starts with good integrated pest management practices.
> 3-year rotation out of tomatoes and peppers
Clean seed or disease-free transplants
Heat treat seed (unless it is pelleted or treated)
Good sanitation in transplant production facility (e.g., new flats or sanitize between uses, sanitize greenhouse after each season)
Inspect transplants and destroy any with symptoms of bacterial disease
Do not work in tomatoes (e.g., tie, prune) when leaves are wet
Either sanitize tomato stakes between growing seasons, or use new stakes each year (preferred)
If you have an outbreak, till in plant debris quickly.
Bacterial canker lesions on tomato fruit
If you are doing all of these things and still need some extra protection from bacterial diseases (e.g., in a wet growing season), pesticides might also be in your IPM toolbox.
In New York, we’re fortunate that so far few bacterial isolates have been found to be resistant to copper. Copper resistance is a major problem in the southern U.S. and we’d certainly like to preserve its efficacy here in NY. Some people are also understandably concerned about the environmental impacts of using a lot of copper on their farms.
Cornell vegetable research programs led by Chris Smart and Meg McGrath have been testing products against our three bacterial diseases – spot (Xanthomonas), speck (Pseudomonas) and canker (Clavibacter) for a number of years. So far, two products – Double Nickel LC (1 qt/A recommended) and LifeGard (4.5 oz/100 gal water) – have been rising to the top. When comparing these products alone to alternating either with copper, both worked better as replacements for some copper sprays than alone. Some research trials only included the biopesticide by itself, but the Double Nickel label states that it should be applied only tank mixed or rotated with copper-based fungicides.
Double Nickel alone (one year of data in Geneva) was as good as copper against bacterial spot. Double Nickel alone (two years of data in Geneva) and LifeGard alternated with copper (one year on Long Island) were as good as copper against bacterial speck. While neither product is registered (legal) for use against tomato canker, in research trials in Geneva, Double Nickel (one year) and LifeGard (two years) alternated with copper controlled canker as well as copper alone. So if you are replacing some copper sprays with either Double Nickel or LifeGard, you’ll likely notice some incidental bacterial canker protection, too.
New to using biopesticides? The New York State IPM Program has a new resource to help. Biopesticide profiles (scroll to bottom of page) for Double Nickel, LifeGard, and seven other products provide information on tank mix compatibility, shelf life, and other practical tips.
Follow the link in the text and scroll to the bottom of the page to find these biopesticide profiles from the NYSIPM program.
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, Biocontrol Specialist with the NYSIPM program, and Chris Smart, Professor in the School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section at Cornell University. Support for this project was provided by the NY Farm Viability Institute.
Follow the link in the text and scroll to the bottom of the page to find these biopesticide profiles from the NYSIPM program.
I’m excited to announce that the New York State IPM Program has a new resource – Biopesticide Profiles!
(Scroll down to the bottom of the page linked above, past the efficacy summaries, which are also cool.)
So far, we have profiles for nine biopesticides registered for use on various crops in NY (including one for use in home gardens) against plant diseases. I plan to add more profiles over time, and will definitely add some bioinsecticides in the future.
These profiles are not meant to replace pesticide labels; always read and follow the label and only use pesticides that are currently registered in your state or province. These profiles have practical details about how to use biopesticides most effectively, including information on mode of action, compatibility with other pesticides, best storage conditions, and shelf life. I’ve also included information on any known toxicity concerns for not just bees, but other beneficial insects like natural enemies of pests.
Just some of the practical information you can find on the NYSIPM biopesticide profiles.
I collected this information from pesticide labels, pesticide manufacturers, EPA registration documents, and peer-reviewed literature, to save you time when you’re considering using a biopesticide. But you should still always read the label.
Take a look and let me know what you think! Which biopesticides should be next on my list?
This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program. Support for this project was provided by the NY Farm Viability Institute.
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
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:
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.
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.
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.
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.
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.
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.
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.
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.
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
Summary of modes of action for biopesticide active ingredients
