Author Archives: Thomas Kuhar

About Thomas Kuhar

Professor and VCE-Vegetable Entomology Specialist Department of Entomology Virginia Tech Blacksburg, VA

Introducing the MyIPM App for vegetables

Commercial vegetable producers have a new tool to assist with integrated pest management (IPM) of diseases and insects in vegetables. MyIPM for Vegetables is the newest resource in the MyIPM app series (https://myipm.app/) for smartphones and smart devices. It currently includes modules for diseases and insects of cucurbits and tomatoes, and additional vegetable crops are planned to be added in the future. Modules contain images and descriptions of diseases and insects; information on available chemical, biological, and cultural management methods for each disease/insect; and tables of labeled fungicides and insecticides that include active ingredients, product names, FRAC/IRAC codes, efficacy, application rates, preharvest intervals (PHIs), and restricted-entry intervals (REIs). Links to additional resources may also be included.

App content is focused on commercial vegetable production in the southeastern U.S., but users outside the southeastern U.S. and home gardens may also find information in the app useful. The development of MyIPM for Vegetables content was led by vegetable entomology and plant pathology specialists from universities within the southeastern U.S. who are part of the Southeastern Vegetable Extension Workers (SEVEW). The SEVEW are also responsible for the popular Southeast U.S. Vegetable Crop Handbook (www.vegcrophandbook) that has been a key resource for commercial vegetable producers in the southeastern U.S. for over 20 years. Author and image credits for specific disease or insect profiles and pictures are available at http://myipm.app/vegetabltes.

MyIPM for Vegetables is not intended to replace product labels. It is meant to be a tool to help vegetable producers make informed IPM decisions. Pesticide users should always read and follow label instructions prior to use. Product labels may change. Product rates may differ depending on the site of application (e.g., field or greenhouse) or type of application (e.g., foliar-applied or soil-applied. Check product labels for additional instructions, precautions, and/or restrictions not listed in the app. Also, check the state registration status of products prior to purchase and use; products may not be registered for use in all states.

MyIPM for Vegetables is free to download for Apple (Apple Store) and Android devices (Google Play). Content is downloaded directly to phones/devices; an Internet connection or cellular signal is not required to access content once it is downloaded. Updates, however, do require an Internet connection or cell signal, and notifications will pop up when updates for downloaded modules and the appropriate Internet/cell connection is available. The MyIPM series began with MyIPM Fruit & Nut that was originally developed by Clemson University in 2012 for peaches and strawberries; the app has since expanded to include other small fruits, tree fruits, and pecans. Other apps in the series include MyIPM Row Crops and MyIPM Hawaii. The Southern Region IPM Center maintains the databases for the MyIPM series apps.

Acknowledgement

This work is partially supported by the Southern IPM Center (Project S23-043) as part of the USDA National Institute of Food and Agriculture Crop Protection and Pest Management Regional Coordination Program (Agreement No. 2022-70006-38002).

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Prepared by Dr. Rebecca A. Melanson, Associate Extension Professor, Plant Pathology, Central Mississippi Research and Extension Center; Dr. Thomas Kuhar, Department of Entomology, Virginia Tech; Dr. Tom Bilbo, Coastal Research and Education Center, Clemson University; and Ms. Inga Meadows, Department of Entomology and Plant Pathology, North Carolina State University.

Latest on chlorpyrifos (Lorsban) regulations from EPA

EPA has finally issued a statement on the revocation of tolerances for chlorpyrifos. For this year, 2024, chlorpyrifos can be used on all product labeled crops. In 2025 and beyond, it will only be allowed on 11 specific crops; alfalfa, apple, asparagus, cherry (tart), citrus, cotton, peach, soybean, strawberry, sugar beet, and wheat (spring and winter). However, there will be further state restrictions on those 11 tolerances coming soon (e.g. chlorpyrifos will only be allowed on tart cherries in MI).


———- Forwarded message ———
From: U.S. EPA Office of Chemical Safety and Pollution Prevention oppt.epa@public.govdelivery.com
Date: Fri, Feb 2, 2024 at 1:23 PM
Subject: EPA Update on the Use of the Pesticide Chlorpyrifos on Food
To: dlfrank@vt.edu

EPA Update on the Use of the Pesticide Chlorpyrifos on Food
The U.S. Environmental Protection Agency (EPA) is issuing an update on the use of the pesticide chlorpyrifos on food.

Chlorpyrifos is an organophosphate insecticide used for a large variety of agricultural uses, including soybeans, fruit and nut trees, broccoli, cauliflower, and other row crops, as well as non-food uses. In a final rule issued in August 2021, EPA revoked all tolerances for chlorpyrifos, which establish an amount of a pesticide that is allowed on food. This action effectively stopped the use of the pesticide chlorpyrifos on all food and animal feed. EPA took this action in response to an April 2021 order from the U.S. Court of Appeals for the Ninth Circuit for the Agency to issue—within 60 days—a final rule addressing the use of chlorpyrifos in food or feed crops, without taking public comment or engaging in “further fact-finding.”

That tolerance revocation rule was challenged by a chlorpyrifos registrant and several grower groups in the U.S. Court of Appeals for the Eighth Circuit. On November 2, 2023, the Eighth Circuit issued a ruling vacating EPA’s final rule and sending the issue of chlorpyrifos tolerances back to EPA for further proceedings. The ruling did not include a timeframe or specific instructions for EPA to take a final action on the use of chlorpyrifos in food or feed crops without public comment.
EPA is issuing a technical correction in the Federal Register that changed the Code of Federal Regulations to reflect the Eighth Circuit’s decision. The Eighth Circuit’s mandate issued on December 28, 2023, finalized the court’s judgment and vacated the Agency’s 2021 rule revoking chlorpyrifos tolerances.

Since the tolerances are currently in effect, growers can now use currently registered chlorpyrifos products on all crops with reinstated tolerances, consistent with directions for use on those product labels. However, such uses may be subject to restrictions by individual states.

The Eighth Circuit’s decision stated that EPA should have considered modifying the tolerances in addition to complete revocation and noted that the Agency had “identified 11 specific candidates” of food and feed crop uses whose tolerances could be modified in a Preliminary Interim Decision EPA issued in 2020. Thus, the Agency expects to expeditiously propose a new rule to revoke the tolerances for all but 11 uses with additional restrictions for geographic location and rate of application to address safety of the tolerances, and potential restrictions for farmworker and other vulnerable populations, and vulnerable species and their habitats. Those 11 uses are: alfalfa, apple, asparagus, cherry (tart), citrus, cotton, peach, soybean, strawberry, sugar beet, wheat (spring), and wheat (winter). These 11 uses were identified in the December 2020 Chlorpyrifos Proposed Interim Decision and represented about 55% of the total chlorpyrifos usage (average annual pounds applied) on agricultural commodities between 2014-2018.

EPA is also engaged in discussions with registrants of chlorpyrifos products to further reduce exposures associated with these 11 uses of chlorpyrifos. EPA will also consider the 2020 Proposed Interim Decision and public comments received on that document.
At this time, any existing final cancelation orders, including any terms for sale, distribution, and use of existing stocks of products subject to those cancelation orders and related return programs for chlorpyrifos products, remain in place, unless and until amended by EPA.
EPA will continue to update the public as it evaluates and takes any actions related to chlorpyrifos use.
For more information, view the Federal Register Notice.

Update on some pest moth activity around Virginia – to end the month of August 2023

We continue to monitor corn earworm, fall armyworm, and beet armyworm at several locations around Virginia. On the Eastern Shore, Helene Doughty observed the following this week: Very low (less than 4 moths per week at several of the Northampton County locations, but 34 CEW moths caught in Painter, VA in Accomack County. Fall armyworm activity has been low throughout Virginia, but Helene did pick up on increased numbers (13 moths) in a bucket trap in Townsend, VA. which is the highest so far this year, but still relatively low. In addition, Helene is monitoring for beet armyworm moth, which can deposit eggs on many different crops from soybeans, cotton, and vegetables like tomatoes, peppers, beans, beets, and spinach. There were high numbers of BAW moths (218) caught in Painter, VA this week. So be on the lookout for this pest. I’ve noticed over the years that they will often attack pigweed and lambsquarters weeds before infesting cash crops.

Hartstack trap on the Eastern Shore of Virginia with nearly 800 corn earworm moths (earlier in August). Photo from Helene Doughty.

In Clover, VA (Halifax County), Mr. Bill Tiver has been monitoring for CEW moths all summer in his commercial sweet corn and has experienced relatively high catch most of the summer. This week he caught 174 CEW moths coming off of 228 moths last week. These are high numbers and has resulted in high CEW pest pressure. He told me that he has sprayed his sweet corn every 3 days, but has still suffered about 15% ears infested with CEW larvae. We don’t have all the information nailed down for thresholds yet, but moth catch over 100 probably suggests that your spray interval should be reduced to every two days. I know, easier said than done, but we can definitely reach heavy CEW flights, which command frequent controls, especially on non-Bt sweet corn.

Corn earworm in sweet corn ear.

In Blacksburg, we have not caught very many CEW moths in our sweet corn (< 5 moths per week), but several harvests of our plots this week yielded about 60-75% ears infested in our untreated control plots, despite low CEW moth trap catch. So, it is hard to figure out what trap catch really means.

European pepper moth – a new pest of vegetables in Virginia

By: Taylore Sydnor (graduate student), Tom Kuhar, and Alejandro Del Pozo (Department of Entomology, Virginia Tech)

The European pepper moth, Duponchelia fovealis, is native to southern Europe and became established on the west coast of the U.S. in 2010. Since, it has been reported in at least 15 states, including as a greenhouse ornamental pest in Virginia a few years ago.  We’ve not heard much more about this invasive species until this summer when numerous pepper plants grown at Virginia Tech’s Homefield Farm in Whitethorne, VA began dying from girdling at the base of stems.  The plants were mature and full of developing pepper fruit, which made it very frustrating. 

Girdling damage to pepper stem from European pepper moth.

With the help of several folks on the ORNAENT Digest Listserv, the problem was diagnosed.  A European pepper moth pupa was found in one of the plants.  Dr. Alejandro Del Pozo from the Virginia Tech Hampton Roads AREC has been monitoring for this pest in nurseries in eastern Virginia and shared some pheromone lures.  This week we captured some EPM moths on delta traps placed in the pepper field at Homefield.  

European pepper moth caught on sticky panel. Grid squares are 1 inch.

Although we have not 100% confirmed the identity of the moths, but they appear to look exactly like what has been described in the literature – based on size and color patterns; and given that that these moths oriented right to the lure septa containing the sex pheromone of EPM, I’m pretty sure that we have this species attacking peppers in Virginia, especially given the distinct conspicuous girdling damage that we observed. This seems to be pretty indicative of EPM. 

What do we know about this pest?

EPM larva photo from :  https://entocare.nl/biological-control/european-pepper-moth/?lang=en

It is a significant pest of ornamental plants and pepper crops. The larvae cause chewing damage to the stems, roots, flowers, and base leaves of crops. The damage appears as crescent-shaped holes on the outer edge of the foliage. The holes left by the larvae can facilitate fungal infection. They produce silk and can be found on the underside of leaves and on the soil surface by the main stem of the plant. We observed mostly stem girdling damage, which ultimately killed many plants.  The European pepper moth larvae can be hard to detect due to small size. Large numbers of this insect can cause significant damage to the crop. It can easily spread through the movement of cut foliage and potted plants. The adult European pepper moth is small (~9-12 mm long) and is brown in color with two distinctive gold bands on the forewings. A female adult moth can lay up to 200 eggs and are white/green in color. A number of insecticides have been shown to provide effective control including diamides, spinosad, pyrethroids, acephate, and Bt among others. Insecticides should target early instar larvae before feeding.   Monitoring for the moth with pheromone lures and delta traps was effective for detecting this invasive pest species. 

Reference used:

https://entnemdept.ufl.edu/creatures/veg/leps/european_pepper_moth.htm

Corn earworm moth catch has really picked up at some Virginia locations and fall armyworms have appeared in the Northern Neck

There are several corn earworm pheromone traps being monitored around Virginia. Many of the Eastern Shore locations have reported relatively low numbers this week, except for one humongous exception, the Eastern Shore AREC in Painter, VA, where Helene Doughty counted nearly 800 CEW moths in just two nights in one of the traps. That’s the highest density that I’ve ever seen in 20 years. It’s really quite striking because the other traps around Northampton County, VA didn’t catch very many.

Hartstack wire mesh trap baited with pheromone lure with ~790 corn earworm moths. Trap located in Painter, VA. Photo by Helene Doughty.

In Halifax County, Virginia, Mr. Bill Tiver, is still reporting relatively high trap catch at his farm. Catch has ranged from 100 to 250 moths per week. Those numbers would likely suggest that CEW control on susceptible crops like sweet corn, tomato, and beans is a must. Sweet corn spray rotations should probably be 3 times a week under that trap catch level. Meanwhile, in Blacksburg, VA, trap catch has been relatively low so far.

Another pest of sweet corn and some other crops is fall armyworm. According to VCE agent, Stephanie Romelczyk, a sweet corn farm in the Northern Neck of Virginia had a fall armyworm outbreak in the whorls, which required a spray of Coragen. We’re all hoping that it did the trick. So in short, it’s definitely time to monitor for the “worm” pests in your late summer crops.

Fall armyworm larvae. Photo from Bill Tiver.
Fall armyworm in sweet corn. Photo by Tom Kuhar.

Continued Monitoring of Corn Earworm and Armyworm Moth Trap Catch in Virginia – July 27, 2023

INSECT MONITORING PROGRAM – 2023

We are monitoring for corn earworm in multiple Virginia locations this year using the Heliothis (mesh) trap baited with the Hercon pheromone lure.  These moths can damage numerous crops including sweet corn, tomatoes, cotton, soybeans and green beans. Traps of 7 or more moths per week indicate the need for intensive scouting of crops for the pest.

Thank you to all of our trap monitors. 

Northampton County and Eastern Shore AREC – Led by Helene Doughty, Research Specialist Sr. | Entomology, Eastern Shore Agricultural Research and Extension Center

Bill Tiver monitoring in Clover, VA (Halifax County)

Brian Currin (Montgomery County, VA)

Week July 20th – July 27th 2023   Helitothis traps have been set up in 4 locations in Northampton County as well as one location each in Accomack County, Montgomery County, and Halifax County to monitor the activity of the corn earworm moths.  Pheromone bucket traps have also been set up in Northhampton County to monitor the flight activity of the fall armyworm. 

Corn Earworm Trap LocationCEW weekly moth catch 7/27/23Pest pressure
Townsend (Northampton Co.)4Low
Cheriton (Northampton Co.)1Low
Machipongo (Northampton Co.)2Low
Nassawadox (Northampton Co.)2Low
Painter (Accomack Co.)20High
Blacksburg (Montgomery Co.)10Moderate
Clover (Halifax Co.)46High

Fall armyworm trap catch has been low so far, although it’s a little early for that tropical moth. 

Fall Armyworm Trap LocationFAW Count 7/27/23FAW Count 7/20/23
Townsend10
Cheriton00
Machipongo10
Nassawadox00

Corn earworm monitoring in southwest and southside Virginia

Written by Brian Currin (Entomology Graduate Student at Virginia Tech). Brian is working on sweet corn IPM for his research. Corn earworm monitoring is continuing in Virginia. As we grow nearer to the time corn begins to silk, and when corn earworm moths lay their eggs, monitoring is important for integrated pest management strategies.

Trap catch for this week ending July 20 at two locations was as follows:

Clover, VA (Data collected by Bill Tiver) 77 moths per wk (high pressure)
Blacksburg, VA (Data collected by Brian Currin) only 2 moths (very low pressure)

The farm in Blacksburg has yet to reach its reproductive stage but during trap monitoring more adults were seen flying in the corn.

Corn earworm moths caught in a Hartstack wire mesh trap.

Corn earworm trap catch from several locations in Virginia – Week ending July 14, 2023

Mid-July is that time of year when we begin to see corn earworm moth activity really pick up in Virginia.  As most of us know, corn earworm moths deposit their eggs on flowering plants of many important agricultural crops including sweet corn, cotton, soybean, and hemp, to name a few.  Eggs hatch in a couple days into larvae that feed on buds, flowers, fruit, and leaves.  Pheromone trap counts of 7 or more CEW moths per week indicates that this pest is active on the farm and could potentially become a pest threat.   

Corn earworm larva. Helene Doughty photo.

Trap catch for this week ending July 14 at several locations is as follows:

Corn Earworm Trap Locationmoths per wk     
Location6/96/156/226/297/67/13
Townsend46734193
Cheriton122001
Machipongo410021
Nassawadox334010
Chatham   405055
Blacksburg   2108
Corn earworm moth catch in Heliothis mesh traps baited with pheromone lures at 6 locations in Virginia.

In summary, CEW moth activity has subsided on the Eastern Shore for the time being as the pest is likely mostly in the larval stage right now.  In Chatham (southside VA) CEW moth activity has remained high >50 moths per week.  Blacksburg, VA has experienced only low moth numbers so far. 

Thank you to Helene Doughty who is monitoring the traps on the Eastern Shore, Bill Tiver who is monitoring a trap in Clover, VA, and Brian Currin who is monitoring traps around Blacksburg.

The Asian Jumping Worm Invasion: Exploring Its Range and Environmental Consequences in Virginia

This article was written by Jordan Thompson, a graduate student in the Department of Entomology working with Drs. Tom Kuhar and Alejandro Del Pozo. Jordan is a graduate student at Virginia Tech studying the Asian jumping worm in Virginia and hoping to find possible control methods. Jordant95@vt.edu

Earthworms might not be the first thing that comes to mind when thinking about invasive species. In fact, you might be familiar with all the benefits of earthworms, such as how they recycle nutrients by breaking down organic matter, making them more available to plants, or how they tunnel through the soil, aerating it, which in turn makes room for delicate plant roots to spread. You may have even purchased a bag of worm castings to spread in your garden, or perhaps you compost with red wigglers. Whatever your association with earthworms, the thought of eradicating them probably didn’t immediately come to mind.

Unfortunately, we now have a worm in the United States that is detrimental to our delicate soil ecosystems. Known as the Asian jumping worm (Amynthas spp.), this invasive earthworm is named for its signature jumping move, a form of predator evasion. They are characterized by their smooth iridescent skin, and their pale clitellum (band). The Asian jumping worm is able to quickly reshape invaded soil ecosystems, resulting in soil that offers minimal benefits to plants and other terrestrial organisms. Where there was once a rich organic matter layer, is now a dusty and lifeless earth, incapable of supporting certain plant life, thereby permanently altering the landscape and inviting other invasive species to move in and thrive. It is evident that these worms are far from being the allies we seek in maintaining a healthy ecosystem.

But how did they get here? Why does it do so well in so many diverse soils? What are the long-term effects of this species? Let’s break it down.

Figure 1. A graduate student from Virginia Tech holds jumping worms dug from a homeowners property in Floyd, Va, a county previously thought to not have the worm.

The Asian Jumping Worm: An Uninvited Guest

The Asian jumping worm originally hails from East Asia and is believed to have been introduced to other regions through various pathways, including horticultural trade, transportation of plants, and contaminated soil or plant material. One key factor contributing to the Asian jumping worm’s rapid spread is its ability to reproduce via parthenogenesis, meaning it can reproduce without a mate. Each worm produces tiny cocoons at around 60 days of age, and each cocoon will hold between 2 and 20 worms – which will again start producing more cocoons in about 60 days. This allows for about 2 generations per year. Often in a soil rich in organic matter, it is not unusual to find hundreds of worms living within an area of a few square feet. The juveniles are almost microscopic, resembling tiny white threads. The cocoons are the size of a mustard seed, and could easily be picked up by animals and humans walking through worm infested soil.

Additionally, the Asian jumping worm’s adaptability to different soil types is another reason for its success as an invasive species. Although it seems to prefer organic matter rich soils, it can thrive in a wide range of soil conditions, even in sandy or clayey soils. Moreover, unlike other earthworms which tend to stay within certain soil layers, Asian jumping worms are more surface-dwelling, making them highly mobile and able to colonize new areas rapidly.

Their ability to survive in colder climates also contributes to their successful spread. Adults will die with the first frost, but leave behind specialized cocoons that protect their eggs and developing juveniles during winter months. This enables them to establish populations in regions that experience cold winters.

In 2022, Asian jumping worms had been confirmed in a handful of counties in Virginia, but a bit of citizen science with the help of Facebook confirms their presence is being severely under-reported or simply, they’ve been surviving unnoticed, and have likely spread well beyond the original counties.

Disturbing the Ground: Impacts on Soil Ecosystems

Asian jumping worms have a voracious appetite for organic matter. They consume leaf litter, mulch, and other organic debris at an accelerated rate, rapidly depleting the available organic material in the soil. This feeding behavior disrupts the soil structure and leaves soil vulnerable to runoff, in addition to reducing the plant life capable of growing there. This specifically affects forest understories, where small trees and shrubs are essential in providing groundcover, soil stability, and forage for wildlife. When Asian jumping worms invade, it can alter the understory therefore altering the native habitat and displacing wildlife and native plant communities.

In residential areas, avid backyard vegetable growers might notice their gardens becoming less prolific. Their plants might begin to struggle and eventually they may see bare spots where once there were lush gardens. Compost piles can become breeding grounds as banana peels and grass clippings become fuel for more generations of jumping worms. In large turf areas such as golf courses, where worm castings already present an issue with aesthetics and maintenance, worms that altogether destroy the soil could spell disaster for ranges trying to maintain quality greens.

There is some understanding of how these worms alter soil chemistry, C/N (carbon to nitrogen) ratios, and soil electrical conductivity, but more research is needed to better understand the severity of these alterations and their long term effects. What we do know is that while soil development takes thousands of years, the Asian jumping worm can significantly alter soil composition in a matter of months. This poses a grave concern and demands our immediate attention.

Current Research and Areas of Study

Researchers from Virginia Tech’s Department of Entomology are actively studying the impacts of the Asian jumping worm in Virginia and exploring potential control methods. Through field observations and laboratory experiments, they are investigating the effects of Asian jumping worms on other soil arthropods, soil nutrient availability, soil electrical conductivity, and more. By understanding the mechanisms through which these worms degrade the soil, researchers aim to develop targeted management strategies. These may include exploring biological control agents, evaluating cultural practices, and assessing the efficacy of chemical interventions.

Current Research and Areas of Study

Researchers from Virginia Tech’s Department of Entomology are actively studying the impacts of the Asian jumping worm in Virginia and exploring potential control methods. Through field observations and laboratory experiments, they are investigating the effects of Asian jumping worms on other soil arthropods, soil nutrient availability, soil electrical conductivity, and more. By understanding the mechanisms through which these worms degrade the soil, researchers aim to develop targeted management strategies. These may include exploring biological control agents, evaluating cultural practices, and assessing the efficacy of chemical interventions.

Jordan Thompson
Jordant95@vt.edu
BS in Environmental Horticulture VT ‘23
MSLFS in Entomology VT ‘25
Jordan is a graduate student at Virginia Tech studying the Asian jumping worm in Virginia and hoping to find possible control methods.

Monitoring Corn Earworm Moths in Virginia

We know that we aren’t the only ones, but we are monitoring corn earworm moths again in Virginia at multiple locations. Pheromone trap counts of 7 or more moths per week indicates that this pest is active on the farm and could potentially become a pest threat to the numerous crops that it attacks such as sweet corn, cotton, hemp, soybean, tomato, and many others. Female egg-laying moths are particularly attracted to flowering plants or plants with fruiting stages.

Corn earworm moth.

Trap catch for this week ending June 29 at several locations is as follows:

  • Townsend (Eastern Shore) – 4 moths
  • Cheriton (Eastern Shore) – 0
  • Machipongo (Eastern Shore) – 0
  • Nassawadox (Eastern Shore) – 0
  • Clover (Southside VA) – 66 moths
  • Blacksburg (southwest ridge and valley) – 2 moths

Thank you to Helene Doughty who is monitoring the traps on the Eastern Shore, Bill Tiver who is monitoring a trap in Clover, VA, and Brian Currin who is monitoring traps around Blacksburg. Moth catch was low on the Eastern Shore and in Blacksburg this week, but rather high at the Clover site; however, sweet corn is in reproductive stages on that farm and probably a very attractive location in southside, VA.