Category Archives: biopesticide

A new resource to help you protect pollinators

honey bee is perched on top of a young developing squash with the flower still attached
Many crops (and plenty of non-crop plants) rely on pollinators. Let’s protect them!

As I’ve discussed before, the natural enemies that provide biological control of pests include both larger creatures (like insects, mites, and nematodes) and microorganisms (fungi, bacteria, and viruses) that combat pests in a variety of ways. Microorganism natural enemies are regulated as pesticides (one type of biopesticide), while the larger natural enemies are not. Growers who are successfully using biocontrol insects, mites, and nematodes usually recognize that they need to apply pesticides in such a way that they are compatible with the biocontrol organisms they use. Take a look at my April post for a summary of online resources that can help you check compatibility of pesticides (including biopesticides) with natural enemies.

Some of these compatibility resources include information on the effects of pesticides (and biopesticides) on bees. Pollinators (including honey bees, lots of other bees, and some non-bees) are very important beneficial insects. You may have noticed that they have found their way into several of my blog posts. So, I wanted to let you know about a brand new resource (hot off the digital presses) to help you protect pollinators.

Image of the cover of the resouces entitled: Pesticide decision-making guide to protect pollinators in tree fruit orchards
“A Pesticide Decision-Making Guide to Protect Pollinators in Tree Fruit Orchards” is a terrific resource to help you choose pesticides (and pesticide combinations) that are least-toxic to bees.

A Pesticide Decision-Making Guide to Protect Pollinators in Tree Fruit Orchards” was written by Maria van Dyke, Emma Mullen, Dan Wixted, and Scott McArt. Although it’s focus is tree fruit orchards (and therefore the pesticides used in them), it should be useful for growers of other crops who want to choose pesticides that are least toxic to bees. A few highlights:

  • It includes information not only on pesticides used alone, but (when available) on synergistic effects when multiple pesticide active ingredients are used together. When you combine some chemicals (either in the tank or in the environment) the mixture is more toxic than both chemicals alone.
  • Where available, it summarizes pesticide toxicity to other bees besides just honey bees (e.g., bumble bees and solitary bees). You can read more about why this is important in this recent article.
  • It describes what we know about sub-lethal (in other words, negative effects on the bees that are less serious than death) effects of pesticides on bees.
  • It includes about half a dozen biopesticide active ingredients.
bumble bee feeding on a purple flower
Pollination is being done by more than just honey bees! This bumble bee (plus many more bee species) are important pollinators in NY.

You might be asking: If a chemical on this table is toxic to bees, will it also be toxic to the insect and mite natural enemies I am releasing or conserving on my farm or in my garden? I wish I had a definitive answer to that. As you can see from the nearly three pages of Literature Cited at the end of this document, collecting these data is a time-consuming process. For now, stick with the compatibility resources that are already available, and ask the companies you buy from (pesticides or natural enemies) about compatibility.

In closing, a huge amount of work went into this resource to summarize so much useful and current (as of October 2018) information in an easy-to-read table. Bravo to the authors! The Pollinator Network @ Cornell has other helpful resources for growers on protecting pollinators. Winter is a great time to make plans for using IPM and protecting the pollinators and natural enemies that are so good for the crops we grow!

What do biofungicides add to vegetable disease management? Part 1 – Introducing the project

butternut squash plants grown on a black plastic-covered raised bed
This summer we compared three biofungicides added to a conventional cucurbit powdery mildew management program in field trials conducted in western and eastern NY and on Long Island. Photo credit: Caitlin Vore, Cornell Vegetable Program

What we’re doing

This summer I have been working with great colleagues (Elizabeth Buck, Dr. Julie Kikkert, Dr. Margaret McGrath, Jud Reid, and Crystal Stewart) on a project funded by the New York Farm Viability Institute looking at the use of biofungicides (Remember what biofungicides are?) in vegetable disease management. Dr. Darcy Telenko (formerly of the Cornell Vegetable Program) helped plan the project before starting her new position at Purdue University, and Dr. Sarah Pethybridge has provided valuable advice based on her extensive work with white mold (including control with biofungicides). BASF, Bayer, BioWorks, Certis, Dow, and Marrone BioInnovations provided product for the field trials.

The project has two goals:

  1. Quantify what biofungicides add to management of cucurbit powdery mildew and white mold in terms of…
    – disease control
    – yield
    – plant health
    – economic value (comparing yield gains to fungicide costs)
  2. Evaluate the utility of NDVI (normalized difference vegetation index) as a measure of plant health and disease detection in fresh vegetables

Why this project?

For both diseases (cucurbit powdery mildew and white mold), we’re considering biofungicides used with other pest management – other biofungicides, conventional chemical fungicides, and/or cultural practices. Biofungicides are not expected to be silver bullets, and they work best when used in an IPM strategy. But when deciding whether or how to use them in your operation, it’s good to know what value you’re getting for the extra costs of purchasing and applying the products. This summer we ran trials in three major vegetable-producing regions of the state: western New York, eastern NY, and on Long Island.

Biofungicides for cucurbit powdery mildew

cucurbit powdery mildew on the upper side of a squash leaf
Cucurbit powdery mildew looks like a dusting of powdered sugar on the cucurbit leaf. These powdery spots start on the underside of the leaf, and then develop on the upper surface of the leaf, so excellent spray coverage is important. Photo credit: Amara Dunn, NYS IPM

For combatting cucurbit powdery mildew, we’re comparing three biofungicides: LifeGard (Bacillus mycoides isolate J), Regalia (extract from the giant knotweed plant Reynoutria sachalinensis), and Serifel (Bacillus amyloliquefaciens MBI 600). All three were applied weekly starting when the plants were small. Then, when the first signs of powdery mildew showed up, we started a rotation of conventional fungicides (Vivando, Quintec, and Luna Experience). These three treatments plus a rotation of all-organic fungicides (LifeGard, MilStop, Serifel, and a mineral oil) are being compared to two control treatments: the conventional fungicides alone, and plants that received no treatment for powdery mildew. We ran the trials on a variety of bushing acorn squash (‘Honey Bear’) that has intermediate resistance to powdery mildew.

Biofungicides for white mold

bean pod half rotted by white mold fungus
Most vegetable crops are susceptible to white mold, with legumes being among the most vulnerable. The name comes from the dense white “tufts” that the fungus forms. These develop into dark, hard sclerotia that can survive for years in the soil. Photo credit: Amara Dunn, NYS IPM

In the white mold trial, we’re looking at Double Nickel (Bacillus amyloliquefaciens strain D747) alone or in combination with Contans (Paraconiothyrium minitans strain CON/M/91-08; formerly Coniothyrium minitans). Next year we’ll look at these biofungicides in combination with reduced tillage at one site. Reduced tillage is another IPM strategy for white mold. The active ingredient in Contans is a fungus that eats the resting structures (sclerotia) of the fungus that causes the disease white mold. Because of this, it needs time to work, and is applied either in fall or spring. The goal is to reduce the number of sclerotia present in the next crop. Next year we’ll collect data on whether application of Contans reduced disease. In the meantime, during the 2018 growing season treatments we tested were Double Nickel, Cueva (an OMRI-approved copper) and no treatment for white mold on snap bean. Previous research by the EVADE Lab at Cornell AgriTech at The New York State Agricultural Experiment Station, Geneva, New York, has shown that Double Nickel is a promising biofungicide for white mold.

What is NDVI, anyway?

In a nutshell, the “normalized difference vegetation index” (NDVI) is a way to quantify how much healthy, green foliage is present. The device we used emits different types (wavelengths) of light (red and near infrared), and measures how much of each type of light is reflected back from the leaves of the plant. Leaves that are dark green and healthy reflect more infrared light and absorb a lot of red light. Less healthy leaves reflect less infrared light. A NDVI value closer to 1 indicates healthier plants. A NDVI value closer to 0 indicates less healthy plants (or more bare ground).

GreenSeeker device over a dark green (healthy) cucurbit plant and a light green (less healthy) cucurbit plant. Arrows show that red and infrared light are reflected differently from these two plants. NDVI values closer to 1 indicate a lot of healthy green leaves. NDVI values closer to 0 indicate less healthy (or fewer) leaves.
NDVI (normalized difference vegetation index) quantifies the amount of dark green foliage based on how much light of different wavelengths is reflected. It is used in some crops to decide when to apply fertilizer, or to help detect below-ground pests. Photo credit: Amara Dunn, NYS IPM

NDVI and similar indices are already used in other crops and in other places to help growers make decisions about when to fertilize, or to help detect parts of a field where a pest may be present. So far in NY, NDVI is not being widely used by fresh market vegetable growers for disease detection. Collecting NDVI data from this project will do two things:

  1. Help us quantify the health of plants. Even though NDVI is not a measure of disease, we would expect to see more healthy foliage if biofungicides are contributing to disease control.
  2. Provide some preliminary data to help us determine whether NDVI measurements could be useful to NY fresh vegetable growers.
people walking through a winter squash field
Growers and industry reps had a chance to visit the 2018 cucurbit powdery mildew field trials shortly before they were harvested. Photo credit: Amara Dunn, NYS IPM

Field meetings were held at each powdery mildew trial location so that local growers could see the trials and hear about the project. We’re currently wrapping up data analysis from the 2018 field season. You’ll be able to learn about results from the first year of this two-year project at winter meetings around NY, in extension newsletters, and here on this blog. Also, stay tuned for Part 2 of this post with details about how these biofungicides work (modes of action), and how to use them most effectively.

This post was written by Amara Dunn (NYS IPM), Sarah Pethybridge (Plant Pathology & Plant-Microbe Biology, School of Integrative Plant Science, Cornell University), and Darcy Telenko (Department of Botany & Plant Pathology, Purdue University).

Managing mosquitoes around your home…there’s a biocontrol for that!

adult mosquito emerging, larvae nearby
An adult mosquito emerges, while other immature mosquitoes (larvae) are still present in this container of standing water. The first step to mosquito management around the home is eliminating standing water wherever possible to prevent mosquito breeding. Photo credit: Matt Frye, NYS IPM

Are mosquitoes bothering you while you enjoy summer in your backyard? An IPM approach is definitely the way to go. Start by checking your yard to see where water might be standing. It could be in toys, flower pots, tarps, wheel barrows, gutters, bottle caps, or so many other places you may not have noticed. Removing standing water from your yard takes away places where mosquitoes breed. Less mosquito breeding, fewer mosquitoes. Always think prevention first when you’re addressing a mosquito problem. Read more about mosquito IPM on the Think IPM Blog and What’s Bugging You?

If there are still some containers you just can’t empty (for example, a lined garden pond), you can find some biopesticides (remember, some biopesticides are biocontrols, too!) in your local garden center to help you with your mosquito IPM. Just make sure you follow all instructions on the label of any product you buy. Read all about mosquito biocontrol on this new fact sheet.

And, if you want to learn so much more about IPM for both mosquitoes and ticks, you still have a little time to register for the 4th Annual NYS IPM Conference on Integrated Management of Ticks and Mosquitoes. But hurry – the conference is August 7th!

 

Mix and Match: Compatibility of biocontrol with other pest management strategies

Delphastus eating whitefly
This small black Delphastus is helping to control whiteflies in a greenhouse. It’s important that other pest management strategies in this greenhouse are used in such a way that they do not harm the Delphastus.

If you were going to tank mix chemical pesticides, you would of course read the label to check for compatibility before mixing products. The same concept applies when using living organisms for pest control. Whether you are using parasitoid wasps, predatory mites, microorganisms, or nematodes, you need to know whether your biocontrols are compatible with each other and any other pest management products you plan to use. For example, a biocontrol fungus might be killed if you tank mix it with (or apply it just before) a chemical fungicide. Insecticides (whether or not they are biological) could be harmful to natural enemy insects and mites. Even some beneficial insects are not compatible with each other because they may eat each other instead of (or in addition to) the pest.

It’s a good idea to keep an updated list of the products and organisms you plan to use for pest management, and their compatibility with each other. For biopesticides (remember the difference between “biopesticide” and “biocontrol”?), start by reading the label (see label excerpt below). You must follow all instructions you find there. Many manufacturers also provide lists, tables, databases, or apps to help you find compatibility information (some links at the end of this post). This is especially useful for insect, mite, and nematode natural enemies, which are not pesticides and do not have pesticide labels. When possible, obtain compatibility information from the manufacturer or supplier you will be using. Different strains of the same microorganism or nematode may have different sensitivities to chemicals.

Compatibility information from Preferal label
This excerpt from the label of the bioinsecticide Preferal provides some information on its compatibility with other products. All instructions on a pesticide label must be followed.

Remember that NY pesticide labels (including biopesticide labels) can be found through the NYSPAD system.

Below are some links to resources from several manufacturers and suppliers of biocontrol products. No endorsement of specific companies or products mentioned in this post is intended. If you know of a link to additional information that is missing, please let me know so that I can include it!

Beneficial nematodes from BASF – This chart describes compatibility of beneficial nematodes sold by BASF with natural enemies and pesticides. Note that only the genus name of each “biological” active ingredient is listed, and that over time, the names of some predatory mites (and whether they belong to the genus Amblyseius or Neoseiulus) have changed.

BASF table describing compatibility
Screen shot of part of a table summarizing compatibility of BASF beneficial nematodes with other pest management tools (in this case, biocontrol insects and mites).

Biobest Side Effect Manual – This side effects manual is available either as an interactive website, or as an app. Choose pest management products by active ingredient or name of the commercial product (including the biocontrol microorganisms Beauveria bassiana and several types of Bacillus thuringiensis). The list of “beneficial organisms” to choose from includes bumble bees and nematodes, but not beneficial microorganisms (fungi, bacteria, and viruses). Select active ingredients/commercial products and beneficial organisms from both lists, then use the legend to interpret the compatibility information that is generated.

Biobest compatibility information
Screen shot from the web-based version of Biobest’s compatibility resource.

 

 

 

 

 

 

 

Compatibility of BioWorks products – Compatibility sheets are linked from each product page.

BioWorks compatibility information
A portion of one of the compatibility sheets provided by BioWorks for their products.

 

 

 

 

 

Koppert Side Effects Information – This information is available either as an interactive website, or as an app. Select beneficial organisms of interest (by either the Koppert product name or the Latin name). Select one or more “Agents” (pest management products) by either the trade name or the active ingredient. Click on Results, and use the Legend to interpret the output.

Koppert compatibility information
Screen shot from the web-based version of Koppert’s compatibility resource.

But does it work? Efficacy of biological control

yellow sticky card for monitoring insect pests in a greenhouse
Biocontrol should be preventative. This yellow sticky card lets you monitor which pests are present and when so that the correct biocontrol (or other management tool) can be used at the right time. It will also help you assess whether your management strategy is working.

If you are thinking about trying biological control, of course you want to know if it is effective. The short answer is, “Yes!” But of course it depends on which biocontrol organism you want to use (and how), which pest you want to manage, and where.

First, you should ask yourself a question: What do I hope to achieve? Some great reasons to use biocontrol for pest management include:

  • Protecting the environment and human health by using more environmentally-friendly pest management strategies
  • Reducing the number of chemical pesticide applications to a crop
  • Preventing (or dealing with) pesticide resistance
  • Meeting a need for a short REI (re-entry interval) or PHI (pre-harvest interval) on the crop
  • Biocontrols are the most effective (and cost-effective) management strategy (definitely true for some pests and settings!)

Second, in what context are you using biocontrol? Biocontrol is best used within a larger integrated pest management strategy. Are you using good sanitation and cultural practices (e.g., adequate but not excessive nutrition and water) that promote healthy plants? Are you regularly checking your plants so that you will notice pests when they are still infrequent (scouting)?

peppers in flooded field
Biocontrol should be used as part of an IPM plan. The excess rain and poorly-drained soil in this field make it unlikely that a biocontrol will be able to protect these peppers from a soil-borne disease.

Biocontrol should also be preventative (before pest pressure becomes high). If you are expecting to use only biological control to solve an already out-of-control pest problem, you will probably be disappointed. Similarly, if environmental conditions are very favorable for a pest, a biocontrol solution will probably be insufficient.

Each year, university researchers, extension staff, and private companies conduct efficacy trials to quantify how well pest management strategies work. Knowing how a biocontrol product/organism performed in these trials can help you decide if you want to try it on your farm or in your yard. It helps to know a little about how these trials are structured. Efficacy trials typically include some combination of the following types of control treatments:

  • non-treated control – plants are exposed to pests (either naturally, or deliberately by the researcher), but no pest management strategy is used; disease/damage severity should be highest in this treatment
  • chemical control – plants are exposed to pests, and a chemical pesticide is applied to manage the pest; sometimes an “industry standard” (what is typically used to manage that pest in that crop and setting) is designated by the author of the study; if no industry standard is designated, comparisons can still be made to the chemical treatment that worked best; disease/damage severity should be very low in this treatment
  • non-inoculated control – no pest pressure (i.e., plants were not deliberately exposed to the pest); sometimes disease or damage still occurs because of natural pest pressure, or because disease or insects spread from other treatments in the trial; disease/damage severity should be lowest in this treatment

Efficacy trials also include statistical analysis. In a nutshell, this analysis tells you whether two values are really different (often described as “statistically different”), or not. If two numbers are not statistically different from each other, it means that only by chance is one larger or smaller than the other. If you did the same experiment again, you might see the opposite relationship. One common way of expressing these differences is by using letters. If two treatments are assigned the same letter, then they are not statistically different. So in the example below, “Bio1” is statistically different from “Bio3” but neither is different from “Bio2”.

graph of sample efficacy trial results
An efficacy trial may compare biocontrol products (Bio1, Bio2, Bio3, and Bio4) to non-treated (high disease/damage), chemical (low disease/damage), and non-inoculated (low disease/damage) controls.

 

When interpreting an efficacy trial, you should compare a biocontrol of interest to the control treatments. Of course, it would be great to see biocontrol products that are just as effective as the chemical control (like “Bio1”), and sometimes they are. Sometimes, a biocontrol may be less effective than the chemical control, but more effective than the non-treated control (like “Bio3”). Sometimes there’s so much variability (represented by the lines extending above and below the blue bars on the chart), that a biocontrol product is not statistically different from either the non-treated control, or the chemical control (like “Bio2”). This makes it difficult to draw conclusions about how well the product worked.

But, it’s not always quite that simple. For example, in these efficacy trials, researchers deliberately expose plants to pests, and often they manipulate the environment to favor pest populations (for example, over-watering plants to promote a soil-borne disease like damping off). While there can be value in assessing product efficacy in a “worst case scenario”, this may be much higher pest pressure than you are likely to encounter on your farm or in your yard. When looking at efficacy trials, you should consider:

  • How much disease/damage was observed on plants that were not protected in any way (non-treated/control)? If it’s too low, it’s hard to be confident that the biocontrols being tested were effective, since even unprotected plants were pretty healthy.
  • How much did the most successful treatment (chemical control) reduce disease/damage? If even the “best” pest management strategy in the trial was not very effective, then pest pressure may have been too high, and it’s not surprising that the biocontrol was ineffective. If you practice good IPM, you likely won’t experience such high pest pressure.
  • How was the biocontrol applied (alone, or as part of a spray program with other products)? Applying single products in an efficacy trial can simplify interpretation, but may not mimic how you plan to use a biocontrol product. If a biocontrol was applied in combination with other products, you should compare the “biocontrol + other products” to the “other products alone” to see what the biocontrol added to pest management.
  • What was your goal, again? For example, if you are hoping to replace one or two chemical applications in a larger spray program with a biocontrol, then a moderately effective biocontrol product (like “Bio3”) may meet this goal.

Because the efficacy of a biocontrol can depend a lot on the environment in which it is used (temperature, humidity, soil conditions, etc.), it’s also a good idea to initially try a new biocontrol in a small area of your farm or yard, and keep notes on what you did and how well it worked for you. You can modify your plan to find what works best for you. The manufacturer or distributor should be able to provide you with important details on how (and for how long) the biocontrol should be stored, and exactly how and when to apply it. And (as always!) if you are using a biocontrol that is also a pesticide (see previous post), make sure that you read, understand, and follow the label.

The following resources summarize efficacy results for biocontrol of plant diseases. As I find efficacy summaries of insect and mite pest biocontrol, I will add them. Or, feel free to suggest efficacy resources you know of in the comments!