Tag Archives: classical biocontrol

EPNs: Good worms

light brown dead grub in a petri dish broken open and surrounded by hundreds of tiny, white, crescent-shaped nematodes
Insect-killing nematodes (tiny white crescent) emerging from a dead insect larva. Photo credit: Peggy Greb, USDA Agricultural Research Service, Bugwood.org

Nematodes are tiny worms. While some of them can damage plants, some prefer to eat insects, and these “good worms” (entomopathogenic nematodes is the technical term, but we can call them EPNs for short) can be helpful biocontrol agents. Teresa Rusinek (Cornell Cooperative Extension eastern NY Commercial Horticulture Program) wrote a guest blog post about her work testing EPNs for control of wireworms in sweet potatoes. Elson Shields (Cornell Entomology) has spent many years perfecting the use of persistent EPNs that are native to New York in agricultural fields where they control insect pests. Kyle Wickings is my go-to expert on using EPNs to manage white grubs in turf. A former graduate student in Kyle’s lab (Max Helmberger) made an amazing video describing the life cycle of EPNs. John Sanderson is the Cornell guru of greenhouse biocontrol (including EPNs for greenhouse insect pests).

So many people have developed so many great materials on EPNs, the purpose of this post is to point you to some of these great resources. Why re-invent the wheel? And if I’ve missed something, please let me know!

John Sanderson (Cornell University) has done some great work evaluating different EPN species for controlling insect pests in greenhouses. You can watch a webinar summarizing this work here.

Carol Glenister (IPM Laboratories) and Elson Shields (Cornell University) did a presentation on “Getting the Most Out of Beneficial Nematodes in Organic Production” for the UMass Amherst Extension Vegetable Program. You can watch the recording on YouTube, and you can read their answers to frequently asked questions online.

Screen shot of Grub ID homepage including the url: grubid.cals.cornell.edu
Proper identification is essential to good IPM, and Kyle Wickings’ Grub ID key helps you do just that.

Need help identifying your white grubs (a critical first step to using EPNs effectively in your lawn)? Kyle Wickings developed a simple key.

Are you concerned about grub damage in your home lawn? Put back that pesticide bottle, and start by scouting and identifying grubs, then apply some EPNs (only if you need them). You can find all the details here.

white grub on soil with a few grass plants nearby
Count how many white grubs you actually have per square foot (and identify them) before deciding if an EPN application would help.

If you are growing alfalfa, Elson Shield’s lab has all the information you need to successfully use EPNs to control alfalfa snout beetles, starting with an overview, and including detailed resources to help you be successful.

Wondering if EPNs can help you control fruit and vegetable insect pests? In consultation with my colleagues, I developed a summary of what we know about which fruit, vegetable, and ornamental pests you are likely to be able to manage with EPNs. More research is ongoing, so this list will continue to evolve.

This work is supported by NYS Departments of Environmental Conservation and Agriculture and Markets.

This post was written by Amara Dunn, Biocontrol Specialist with the NYSIPM program, but was only possible due to the great work done by colleagues. All images are Amara’s, unless otherwise noted.

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

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

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

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

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

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

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

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

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

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

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

 

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

Learn more about classical biocontrol

Several brown, slimy-looking larvae on a leaf of a lily plant that has been chewed up. A small black wasp that is less than a third of the size of the larva is perched on one of them.
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.

Held against the background of a person's hand, you can see the underside of a hemlock branch. It looks like there are small tufts of white cotton where each needle attaches to the branch.
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?