Category Archives: Insect

Asiatic garden beetle monitoring–May 23, 2024 update

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In 2023 there were multiple, scattered reports of severe defoliation and/or death to cotton seedlings caused by Asiatic garden beetle (AGB) in Virginia and northeast North Carolina. Infested cotton areas varied in size, with some reaching 10 acres. AGB feed on roots (as grubs) and foliage (as adults) of many different host plants. The adults hide in the soil during the day and feed at night. AGB prefer sandy soil over heavier soil. When we visited the infested cotton fields, we often found AGB in the soil below weeds (e.g., marestail) and volunteer soybean plants.

Asiatic garden beetle injury to seedling cotton, 2023 season, Sussex County, VA.

This April the Tidewater Agricultural Research and Extension Center’s entomology program began sampling field “hotspots” from the 2023 season using soil samples, pitfall traps, and a black light trap. We found AGB grubs in soil samples from fields in Wakefield and Sussex County, VA, but did not find them in a northeast North Carolina field infested last year. AGB grubs can be differentiated from other white grubs by their “puffy cheeks.”

Soil samples (about a shovel full) to monitor for Asiatic garden beetle grubs.

The black light trap is being operated in Sussex County, VA; it had a peak of 114 AGB adults (total per 3 nights) on May 9, 2024, followed by a sharp decline in captures. Other states have reported a single generation of AGB per season, but we plan to keep monitoring for several more weeks. We are still finding grubs and pupae in our soil samples. Pitfall traps placed in the field, designed to capture crawling adults (not flying due to cool temperatures), have not captured any AGB so far.

Asiatic garden beetle adult (size is similar to a coffee bean). Image credit: Whitney Cranshaw, Colorado State University, Bugwood.org

Cotton infestations and seedling injury from 2023 may have been due in part to cool May temperatures, keeping AGB adults on the ground, feeding in the cotton fields where they emerged; the cooler weather also limited cotton seedling growth.

We’ll provide further updates as we learn more. If you suspect an AGB problem in your seedling cotton, please feel free to reach out to me, or contact your county Extension Agent.

Acknowledgements: We are grateful for the financial support provided by Cotton Incorporated and the Virginia State Cotton Support Committee, and for the assistance provided by local cotton growers.

Cereal leaf beetle egg peak for Suffolk, VA (2024 season)

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Yield reductions in small grains can result from cereal leaf beetle larvae feeding on leaf photosynthetic tissue. Infestations in Virginia are sporadic, but if you scout for them I wanted to share the following information. A temperature-based model indicates that Suffolk (Virginia) will reach the egg peak for this pest on March 22, 2024 (that’s the day when 182 degree days have accumulated). The model uses January 1 as a biofix; a lower development threshold of 8℃, and an upper development threshold of 25℃.

Eggs are yellow-orange, elliptical, about 1/32-inch long, and are often found along the midvein of the leaf.

Cereal leaf beetle eggs

The larval peak follows the egg peak by an average of 17.5 days, which is predicted to fall during the second week of April for Suffolk.

Cereal leaf beetle larvae

To scout for cereal leaf beetle, inspect 10 tillers (stems) in at least 10 different sites. If you are seeing mostly eggs, you should scout again in 5-7 days when some have hatched into small larvae. The eggs may be parasitized. Virginia’s threshold is 25 eggs + small larvae (total) per 100 tillers. At least half of that 25 should be larvae. An insecticide spray, if needed, should target the newly-hatched larvae. There is only one generation per year.

Peanut Burrower Bug in Virginia peanuts

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Peanut Burrower Bugs (Pangaeus bilineatus) have been collected and identified, by the Virginia Tech Insect Identification Laboratory, on the Tidewater AREC farm. Peanut burrower bugs are a subterranean pests that feed on pods and pegs of developing peanuts. Burrower bugs have most likely been around for a while but Lorsban (active ingredient is chlorpyrifos) was controlling their populations. Since the removal of Lorsban (chlorpyrifos) from market shelves, there are no effective chemical controls for producers. Damage caused by the peanut burrower bugs looks similar to stink bug damage. This damage is only seen when peanuts are shelled. The skin is removed at buying points by graders: The insect does not leave an indicator of damage on the shell of the peanut. Peanut burrower bug is more of an issue in hot dry years, and they are just as sporadic as southern corn rootworm.

In terms of prevention, there is no chemical control with the loss of lorsban. Some producers have gone back to using a moldboard plow and completely turning over the soil. Some producers have been planting earlier hoping for a thicker hull development earlier in the season. Damage is minimal in Suffolk, VA, but it is something to keep in mind.

Peanut burrower bugs can cause a wide range of damage, which is not visible until after the peanuts are harvested and shelled.
Peanut burrower bug poses a complex problem for producers | Colquitt County Ag Report (uga.edu)
Peanut Burrower Bug (tamu.edu)

Corn earworm update for September 7, 2023

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Black light trap captures for corn earworm moths averaged 15 per night in Greensville and 10 per night in Suffolk this week. Here is the Table. Our adult corn earworm cypermethrin vial tests are at 20% survival for the 5 microgram/vial rate of this pyrethroid insecticide (n = 754 moths tested, Suffolk, VA). I’m sweep netting high numbers of corn earworm larvae in R5 soybean at our research center, along with an increasing soybean looper population.

Video tutorial on how to scout for Japanese maple scale crawlers

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Crawlers are the most vulnerable stage to control the Japanese maple scale under nursery conditions. Monitoring crawler activity throughout the growing season will aid to refine the timing of deployment of any control tactic.

Graduate student Mollie Wyatt (Virginia Tech, Entomology Department) took the lead on creating a video showing us the step-by-step process on how to do the ‘tape method’ for monitoring crawler activity for this pest in ornamental trees.

You can click on the link below to access to a short version of this video. You might need an actual computer to watch that clip. The full version will be posted soon on our VCE website. Stay tune! Funding to support this project was provided by the Southern IPM Center and USDA NIFA.

https://drive.google.com/file/d/1Rw8N2rirx8BeryyEg4CX4N_Md0lhFsAI/view?usp=sharing

Corn earworm update for August 24, 2023

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Black light trap captures of corn earworm moths decreased this week in southeast Virginia. Sara Rutherford in Greensville had 13 per night; Scott Reiter reported 7 per night (Prince George-Templeton) and 8 per night (Prince George-Disputanta); Suffolk dropped to 20 per night. Here is the Table. Scott was getting 2 to 8 larvae (mostly in the 0.5-inch size range, or 4th instar) in his soybean samples this week. I had larval numbers range from 1 to 10 larvae per 25 sweeps in untreated Suffolk and Greensville soybean. There is no substitute for scouting your fields. To calculate your thresholds, please see this online calculator

Corn earworm update for August 17, 2023

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Black light trap captures of corn earworm moths increased this week. Sara Rutherford reported an average of 27 moths per night for Greensville; in Prince George, Scott Reiter had 13 per night (Templeton) and 18 per night (Disputanta); in Suffolk, we saw an average of 62 per night. Here is the updated Table

In our August corn earworm vial tests, 19% of moths survived the 24-hour exposure to 5 micrograms of cypermethrin. This is below our 10-year average of 32% survival.

Corn Earworm Update – Aug. 10, 2023

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The presence of corn ear worm moths in the blacklight traps have increased this week. Sarah Rutherford in Greensville (Jarratt) recorded an average of 13 moths per night; Scott Reiter in Prince George had 62 moths per night in Wells and 42 per night in Rosbicki; The Tidewater AREC entomology team recorded an average of 50 moths per night in Suffolk.

Corn earworm update for Aug. 2, 2023

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Corn earworm moth catches are starting to pick up in our black light traps, but at this point are still fairly low. Sara Rutherford in Greensville (Jarratt) averaged 6.8 moths per night; Scott Reiter in Prince George had 3 per night in Templeton and 1.5 per night in Disputanta; the Tidewater AREC entomology team (Benjamin McManaway and Gwenyth Gregory) captured an average of 4.4 moths per night in Suffolk. Here is the Table

Pheromone trap catches of corn earworm moths in Suffolk increased this week–we are using these moths as part of our insecticide resistance monitoring program. So far we have tested 76 moths, with 17.6% surviving a 24-hour exposure to cypermethrin (a pyrethroid insecticide).