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.
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.
With current rainfall from Idalia and cooler temperatures over the next three days, peanut fields with a history of SB (Sclerotinia blight) should be sprayed soon with a fungicide that can reduce losses to that disease.
SB is favored by rainfall and periods of high relative humidity, but what really triggers it is cooler temperatures. The current forecast is for daily highs to be in the upper 70s and 55 to 60° lows over the next three days. Those lows will really get SB cranked up! I have already seen SB slowly moving in my trials and I’ve heard reports that peanut growers are seeing it in some of their fields. According to Dr. David Jordan, peanuts are likely 1 week behind in maturity compared to last year due to the record cool temperatures observed in May, so there’s plenty of time for SB to do some damage.
This late in the game the second spray of Miravis tank-mixed with Elatus surely has been applied, or is about to based on when the first spray was applied. I do not recommend the first application of the Miravis/Elatus tank-mix be used this late, mainly due to it’s having no curative activity on either LLS (late leaf spot) or SB and for reducing risk of fungicide resistance to those chemistries. I’m quite hesitant even to recommend the second application at this time.
The safe bet is applying Omega 500 for SB tank-mixed with an effective fungicide for LLS. If you sprayed Miravis/Elatus the first week of August, I’d prefer to use Omega 500 at 1.0 pt/acre in the next few days to protect against SB. If you have a field that’s notorious for severe losses to SB, you can go to 1.5 pt/acre, but I haven’t seen a big difference in control between the two rates. I consider Omega 500 to have 3 weeks of activity against SB. So if it’s been 3 weeks or more since you applied Omega 500, I’d be thinking about that 2nd application right about now. Remember, Omega 500 has a 30 day PHI (preharvest interval). That’s 30 days prior to harvesting with a peanut picker, not 30 days until digging.
One saving grace is that temperatures go up again next Monday and maintain daily lows in the upper 60s/low 70s and highs in the upper 80s/low 90s until about September 11th according to the current forecast. Most peanuts in the region have fairly dense canopies now, so while the higher temperatures may slow SB development, the disease will continue to progress and potentially explode again if favorable conditions present themselves.
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.
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 Location
CEW weekly moth catch7/27/23
Pest pressure
Townsend (Northampton Co.)
4
Low
Cheriton (Northampton Co.)
1
Low
Machipongo (Northampton Co.)
2
Low
Nassawadox (Northampton Co.)
2
Low
Painter (Accomack Co.)
20
High
Blacksburg (Montgomery Co.)
10
Moderate
Clover (Halifax Co.)
46
High
Fall armyworm trap catch has been low so far, although it’s a little early for that tropical moth.
Within the past week two outbreaks of FLS (frogeye leaf spot) have been reported in southeastern Virginia. Southeastern Virginia has experienced warm, humid conditions and frequent rain events which favor FLS development. Both outbreaks were found on soybean varieties susceptible to FLS in the R1 stage. This creates an issue as the recommendation for fungicide timing on soybeans is R3-R5. Having disease already in the field is also less than ideal as fungicides perform better if applied prior to symptom development. To deal with this situation I recommend:
Scout fields for FLSand Target…
fields planted to FLS-susceptible varieties and with a history of frogeye leaf spot
fields in continuous soybean production
fields in short rotations between soybean crops
fields with conservation tillage
low-lying areas of fields
FLS symptoms found in the upper canopy last Friday.
If you have fields that meet the above risk factors you should use a preventive fungicide application no sooner than R1. If you find FLS in R1 soybeans spray immediately with a FRAC Group 3 (DMI, triazole) fungicide as these fungicides have some curative activity. University pathologists in the U.S. have had the best results with Domark, Topguard, Lucento, Revytek, and Miravis Top when spraying after FLS is detected. Follow-up sprays may be needed if FLS continues to progress.
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.
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 Location
moths per wk
Location
6/9
6/15
6/22
6/29
7/6
7/13
Townsend
46
7
3
4
19
3
Cheriton
1
2
2
0
0
1
Machipongo
4
1
0
0
2
1
Nassawadox
3
3
4
0
1
0
Chatham
40
50
55
Blacksburg
2
10
8
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.
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.
When I look at how small my peanuts are today, spraying them for leaf spot seems hard to imagine. We’re at least 40% behind in peanut heat units compared to previous years. Slow, late development tells me we will likely be digging peanuts later than usual. How does that affect initial fungicide spray program decisions?
To me, digging later means there’s potential to apply more fungicide sprays, which can get expensive. My response to late-developing peanuts is to delay the first leaf spot application. The rule of thumb NC and VA have used for initiating leaf spot fungicide programs is 60 DAP (days after planting), but no later than July 10th. But with peanuts so far behind I’d consider shifting that back to no sooner than July 15th, maybe a little later to extend disease control later in this season and to avoid “extra” leaf spot sprays. Not only for leaf spot, but also for soilborne diseases like SSR (southern stem rot/white mold) and SB (Sclerotinia blight). This may be especially true for SB as temperatures cool down as we approach harvest and cool temps favor SB. Saving expensive SB fungicide applications in lieu of a later harvest makes sense to me. I recommend keeping up with peanut heat units and the leaf spot and SB advisories on the Peanut Cotton InfoNet (url link here) or call the Peanut Hotline at 1-800-795-0700. That way you can gage peanut maturity and disease risk to help make fungicide timing decisions.
If questions arise concerning peanut disease management this season please don’t hesitate to reach out to me. My contact info is below:
address: 6321 Holland Rd., Suffolk, VA 23437 office phone: (757) 807-6536; mobile phone (preferred): (757) 870-8498 email: dblangston@vt.edu
