Just in time for spring, the New York State Integrated Pest Management Program’s annual conference is all about growing vegetables in your home garden. Whether you have a few containers on a porch or balcony, or some carefully planned garden beds in the backyard, there’s always room for more IPM in your garden! We have a great line up of speakers from around New York, covering topics from garden planning and soil health to composting, weeding, and choosing plant varieties that resist pest attacks. Yours truly will be talking about insects that are natural enemies of pests and make great allies in the home garden.

As with so many things over the past year, this event will be virtual, which means it’s even easier for you to attend. To combat “Zoom fatigue” we’ve planned it for two half days (April 27 and 28). After the sessions on April 27, you’ll be able to stick around and chat with speakers and other attendees about your choice of garden topics while you enjoy your lunch. (Sorry, no lunch provided with meeting registration. )

We invite attendees to choose the registration price that works for you (between $10 and $20 for both days). But please don’t let cost keep you from attending! We want this meeting to be accessible to everyone. See the meeting page (linked in the next paragraph) for more info.

All the details for how to register and the schedule of topics and speakers can be found here. Please register by April 21, if possible. The link to sign up for a discussion topic at the end of the first day of the meeting will be sent out shortly after April 21, and you’ll be assigned to a discussion topic on a first-come-first-serve basis.

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

There are a lot of different “biological” products on the market. Frankly, the terms used to describe them can be a little confusing. So let’s take a closer look at a few terms and exactly what they mean.

First, what is a pesticide? According to the Cornell Pesticide Management Education Program, “a pesticide is any substance or mixture of substances used to kill pests or to prevent or reduce the damage pests cause”. Pesticides include repellents, but exclude traps (if they are only mechanical or physical). The important point is that pesticides are defined by their purpose, not by their ingredients. Pesticides may be chemicals, plant extracts, or microorganisms, but their purpose is to prevent pest damage. Pesticides are regulated by the Environmental Protection Agency (EPA), and must always be used according to their labels.

“Biopesticide” is a term defined by the EPA as “certain types of pesticides derived from such natural materials as animals, plants, bacteria, and certain minerals.” All biopesticides are pesticides, and must be handled and applied as such. They fall into one of three groups:

• Microbial – active ingredient is a living microorganism (fungi, bacteria, viruses, protozoa) or a product made by a microorganism
• Biochemical – natural compounds including both plant extracts and naturally-occurring chemicals
• Plant-incorporated protectants – the products that result from inserting new genes into plants (i.e., the result of genetic engineering)

Biopesticides control plant diseases in five ways:

1. Consuming or parasitizing the pest, directly – An example of this is a beneficial fungus that eats a pest fungus, or a beneficial fungus that infects and kills a pest insect.
2. Poisoning the pest – Some microorganisms produce antibiotics that are toxic to pests. There are numerous bacteria that do this.
3. Crowd out the pest – Pest microorganisms (pathogens) can’t colonize and invade a plant if the surface of the plant (leaves, roots, etc.) are already covered with beneficial microorganisms. There just isn’t space.
4. Stimulating plant defenses – Although very different from human immune systems, plants do practice self-defense. Beneficial microorganisms can cause plants to “turn on” their defenses before they encounter a pest. The plant is then less likely to be damaged by the pest.
5. Promoting plant growth and stress tolerance – Healthier plants are more resilient when faced with a disease. If the purpose of the product is to protect the plant from disease, this would be its mode of action.

Check out this blog post for more information on how biopesticides that target insect pests work.

Sometimes a single biopesticide functions in more than one of the above ways. But, again, the purpose of using a biopesticide is to control a pest. Biostimulants have a different primary purpose: enhancing plant health (which can lead to the plant being less susceptible to attack by a pest). The European Biostimulants Industry Council has defined a biostimulant as “containing substance(s) and/or microorganisms [e.g., bacteria and fungi] whose function when applied to plants or the rhizosphere [soil surrounding plant roots] is to stimulate natural processes to enhance/benefit nutrient uptake, nutrient efficiency, tolerance to abiotic [non-biological] stress, and crop quality.” This definition is also supported by the Biological Products Industry Alliance. No regulatory definition of biostimulant currently exists in the United States. Biostimulants are registered either as fertilizers or as biopesticides, depending on the claims (pest control vs. plant health enhancement) made by the registrant.

Biostimulants can include a wide variety of ingredients, which can be placed in the following four categories:

• Microorganisms (e.g., fungi and bacteria)
• Extracts from plants or seaweed
• Organic (i.e., carbon-containing) molecules including various components of soil organic matter
• Inorganic (i.e., not carbon-containing) elements or molecules

Biostimulants can enhance plant health in multiple ways. In some cases, scientists don’t yet know how a biostimulant enhances plant health, just that it does. Like biopesticides, a biostimulant may have more than one of the following modes of action:

1. Improve soil quality by impacting soil characteristics like water holding capacity, structure, or aeration
2. Improve plant access to nutrients already present in the soil
3. Stimulate plant defenses or otherwise increase the plant’s tolerance to stress (from biological or non-biological sources)
4. Improve root growth of the plant (so that the plant can take up nutrients better)
5. Improve the quality of something produced from or by the plant (e.g., improved flavor or nutrition of fruit)

And where does biocontrol fit in? In several places on this blog, I have noted that definitions of biocontrol vary. I think most scientists who study biocontrol would agree that a living microorganism that is applied to the soil or to a plant and that consumes or parasitizes a pest (a type of biopesticide) is a biocontrol agent. But there are lots of gray areas. What if the biopesticide contains only products of the microorganism which are antagonistic to the pest, and no living organisms?

These are debates I’d rather not spend a lot of time on (at least on this blog). Suffice it to say that at least some biopesticides are also considered types of biocontrol. There are a lot of biological products available to you. Exactly how each is classified (biostimulant versus biopesticide) makes a difference in how the product can be legally used. Know what you are using and why. And always, always, always read and follow the label!

Biocontrol can be an important part of an integrated pest management strategy (learn more about “IPM in a Nutshell”). For example, biocontrol organisms that support plant health can make them less susceptible to the pests that damage them (prevention). If something needs to be applied to reduce pest populations (or keep them low), biocontrol products tend to be less harmful to other critters or people than chemical pesticides (choosing a pest management strategy with low environmental impact).

In the images at the top of this blog, you can see some examples of biocontrol. From left to right…

Syrphid flies are often seen foraging for pollen and nectar on flowers, but immature syrphid flies (larvae; not pictured) also eat pest insects. (Photo credit: Ken Wise)

Some bacteria produce compounds that slow the growth of pest fungi, or even kill them. (Photo credit: Carly Summers)

Many different species of parasitic wasps use their stingers to lay eggs inside pest insects (which is what happened to this aphid). The egg hatches, and the developing wasp eats the pest from the inside out, eventually leaving through the exit hole seen in this picture. (Photo credit: Ken Wise)

Some stink bugs are pests, while other stink bugs (like this one) are predators of pests. (Photo credit: Ken Wise)

Adult ladybugs are more easily-recognized than immature ladybugs (larvae), like the one that is eating aphids in this picture. (Photo credit: Ken Wise)

In the background is a picture taken under the microscope of nematodes (tiny worms). Some nematode species seek out and enter soil-dwelling pest insects, carrying bacteria that will kill the insect. (Photo credit: Maxwell Helmberger)

Posts on this blog will explain how biocontrol is already contributing to IPM in New York, and how its use in pest management could be improved. The information is posted by Amara Dunn, Biocontrol Specialist with the New York State Integrated Pest Management Program. If you have questions about biocontrol, you can contact Amara by email (arc55@cornell.edu), call her office (315-787-2206), or leave a comment on this blog.