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.

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.

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.

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. 

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.  

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?

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

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.

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.

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 20^th – July 27^th 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. 

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

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.

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.   

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

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.

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.

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.

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.

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.

By Helene Doughty and Tom Kuhar

Everyone is gearing up and planning for potato planting to begin soon! With two primary insect pests of great economic importance: Colorado potato beetles and wireworms, growers are sometimes perplexed on what the best option may be or looking for that new product that will solve all their insect problems.

COLORADO POTATO BEETLES:
No new products have been registered for Colorado potato beetle control for 2023. However, at-planting neonicotinoid insecticides are still working well in our area (thankfully!). Field trials at the ESAREC in 2021 comparing labeled at-planting insecticides yielded great results for Colorado potato beetle control, up to 56 DAP (Figure 1 and 2). Similar residual efficacy has been shown on commercial farms on the Shore as well based on previous assays from 2021.

And for those pesky beetles infesting fields later in the season (likely from neighboring potato fields from the previous year) once the at-planting insecticide has worn off, there are still numerous options for foliar control (being mindful to rotate to a foliar insecticide in a different IRAC group) (Figure 3). A couple new insecticides with new mode of actions should be available later in 2023 or 2024, which have performed very well in our CPB efficacy trials; these include plinazolin a new Group 30 mode of action, and Calantha (a new RNAi insecticide that is highly specific to CPB and not toxic to any other organisms).

WIREWORMS:

Questions about wireworm control come back every year. With recurring problematic fields, growers are always in search of new options. Based on 15 years of research at the ESAREC, the combination of Regent (fipronil) with a neonicotinoid (thiamethoxam or imidacloprid) at planting still offers the best control for seedpiece protection. A new option is available in 2023 with a group 30 insecticide, broflanilide, currently marketed under the trade name Nurizma. We are looking forward to testing it as an at-planting insecticide in our potato field trials in the upcoming season.  We are also interested in assessing the wireworm suppression ability of this same insecticide applied as a seed treatment to wheat cover crops.  Research has shown that this can significantly reduce wireworm populations in a field for subsequent crops like potato. 

More research work in the upcoming years will continue to focus on understanding the biology of this pest in its larval and adult stage as well as reduction of wireworm population in fields for potato production through seed treatments in rotational crops.

This week I visited several vegetable farms in southside (southcentral) Virginia and found beet armyworm infestations at all of the farms. This is not good news as this insect pest can be difficult to control. One field of Brussels sprouts had been sprayed with a pyrethroid and with Lannate the spray before and had a healthy population of beet armyworms doing a lot of damage (see photo). I saw mostly young larvae and even some egg masses (see photo). Based on my experience, this pest is resistant to those two classes of insecticides.

History and Pest Status of the Beet Armyworm in the U.S.

The beet armyworm (BAW) is a widely distributed polyphagous insect pest of >90 species of plants and cultivated crops, including alfalfa, asparagus, bean, beet, broccoli, cabbage, cauliflower, celery, chickpea, corn, cotton, cowpea, eggplant, lettuce, onion, pea, peanut, pepper, potato, radish, safflower, sorghum, soybean, spinach, sugarbeet, sweetpotato, tobacco, tomato, and turnip.  The insect also feeds on fruit and ornamental plants.  The BAW is native to Southeast Asia, but has spread throughout much of the world.   It was first discovered in North America in the late 1800’s on the west coast, and reached the southeastern U.S. by the 1920’s.  As it is a tropical insect, it lacks a diapause and ability to overwinter in colder (temperate) climates.  High populations of BAW occur in the southeastern and southwestern states in the spring, and highly mobile migrants usually make their way northward each summer to the Mid-Atlantic states, Colorado, and northern California.  Occasionally the pest is found as far north as New York and even Canada. 

Damage

BAW larvae feed on foliage and fruit.  When they are young, larvae feed gregariously, usually in great numbers, where they skeletonize and web leaves.  As they mature, larvae devour more foliage and may burrow into fruit or heads of plants.  When BAW outbreaks occur in a region, they are conspicuous and often become the primary pest control focus of growers of numerous field and vegetable crops because of the sheer numbers of larvae and their ability to move from crop to crop.  If they are not controlled, BAW infestations can sometimes result in total crop losses.  The insects have a high reproductive potential; eggs are laid in clusters of 50 to 150 eggs, and female moths can produce over 1300 eggs in a lifetime.  In addition, eggs are well protected from the environment and predators because they are usually deposited on the undersides of leaves and are covered with cottony scales deposited by the female moth.  This usually results in numerous larvae infesting a single plant after egg hatch. 

Insecticide Resistance in the Beet Armyworm

BAW has a high propensity for developing resistance to insecticides. In the southeast and southwestern states, the relatively high abundance of BAW coupled with large acreages of valuable crops has stimulated a long history of intense insecticide use . Not surprisingly, this has resulted in the development of resistance to a diverse array of pesticide classes, including chlorinated hydrocarbons, organophosphates, carbamates, pyrethroids, and benzoylphenylureas. Some recommended insecticide options include the diamides such as Coragen, Harvanta, Beseige, Elevest, etc.., spinosyns like Radiant or Blackhawk or Entrust for organic growers. Bt products like Dipel, Agree, Xentari, Javelin, Deliver, etc.. will provide very good control of small larvae. Proclaim and Avaunt are also effective products from past efficacy trials.