Category Archives: Insect

Reports of Soybean Aphids

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First, I would like to introduce myself. I am Tim Bryant, the new assistant professor of entomology and extension specialist at the Tidewater AREC, in Suffolk, VA. I did my master’s degree here at the TAREC under Dr. Sally Taylor, and I am excited and grateful for the opportunity to come back and work with the farming community in Virginia. I am also looking forward to continuing to provide updates on this platform as regularly as we have updates to provide. Now, on to a quick update from my first few weeks on the job…

Soybean aphids have been reported in Mecklenburg and Prince George counties (First reports 8/28). Aphids can reproduce asexually, and are capable of rapid population growth under the right conditions, so close monitoring is important. Our threshold for managing soybean aphids is 250 per plant at R4 (full pod) or prior, and 1000+ at R5 (beginning seed) and beyond. The below image shows 300 aphids on a single leaflet as a point of reference (Photo credit: Roger Schmidt, University of Wisconsin-Madison, Bugwood.org). There is likely to be multiple developmental stages of aphids present at one time, and early stages are very small.

There are a couple key considerations for managing aphids; 1) they are highly susceptible to population crashes from natural enemies or weather events, and 2) broad-spectrum insecticide applications (i.e. pyrethroids) may kill aphids, but also the afore-mentioned beneficial insects. Eliminating beneficials can potentially flare up spider mites or other pests later on. If you think you may have an aphid problem, scout several areas of the field to estimate the number of aphids per plant and pay close attention to the number of beneficial insects present. Where we scouted for aphids, there were also large numbers of lady beetle adults and larvae, which are excellent aphid predators. If you reach the aphid threshold, sample again in 5-7 days to ensure the population has not crashed. Narrower spectrum insecticides (e.g. sivanto) may preserve some beneficial insects if an application for aphids is made. See our pest management guide (beginning on page “4-62”) for more details on labeled products, application rates, etc.

The below image shows a lady beetle larvae, which were found in abundance along with the aphids we are reporting on here, feeding on an aphid (Photo credit: Winston Beck, Iowa State University, Bugwood.org).

Corn earworm and stink bug update for September 5, 2024

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Corn earworm (=bollworm) moth captures in local black light traps increased this week. The average number per night was 12 in Greensville County, 14 in Prince George/Disputanta, and 70 in Suffolk. Here is the Table. Scouting soybean in these locations indicated that larval numbers are low. Here is the customizable Corn Earworm Larval Threshold Calculator for Soybean. Thanks to Sara Rutherford, Scott Reiter, and the Tidewater AREC entomology crew for their reports.

Stink bugs tend to increase in soybean this time of year. This week in Greensville County we were finding a mixture of brown marmorated, green, and brown stink bugs. The threshold in soybean for grain is 5 stink bugs per 15 sweeps (all stink bug species combined) until the leaves begin to senesce and fall–at which point the threshold numbers are doubled to 10.

Insect pest pressure and beneficials will vary by field. Please be sure to scout your fields and check the Virginia Cooperative Extension thresholds.

Corn earworm/bollworm update for August 22, 2024

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Corn earworm (= bollworm) moth catches in southeast Virginia black light traps declined further this week. The average number captured per night was 16 in Greensville, 12 in North Dinwiddie, 2 in Prince George/Disputanta, and 6 in Suffolk. Here is the Table. Reports of soybean fields at larval threshold are coming in.

Corn earworm/bollworm update for August 15, 2024

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Corn earworm (= bollworm) moth catches in southeast Virginia black light traps declined this week. The average number captured per night was 28 in North Dinwiddie, 22 in Prince George/Disputanta, and 22 in Suffolk. Here is the Table.

Here is the corn earworm larvae threshold calculator for soybean. Additional information for corn earworm sampling, decision making, and insecticide options can be found beginning on page “4-56” of the Virginia Cooperative Extension 2024 Field Crops Pest Management Guide’s Insect Control in Field Crops Chapter.

For cotton, bollworm thresholds for Virginia and insecticide options can be found beginning on page “4-80” of the above publication.

Corn earworm/bollworm update for August 8, 2024

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Corn earworm (= bollworm) moth catches were exceptionally high this week, continuing to climb in Dinwiddie, Prince George, and Suffolk, VA black light traps. The average number captured per night was 38 in Greensville, 79 in North Dinwiddie, 72 in Prince George/Disputanta, and 124 in Suffolk. Thanks to Sara Rutherford, Scott Reiter, and the Tidewater AREC entomology crew for their reports. Here is the Table.

Corn earworm/bollworm update for August 1, 2024

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Corn earworm (= bollworm) moth catches increased greatly this week in southeastern Virginia black light traps. The average number captured per night was 50 in Greensville, 42 in North Dinwiddie, 39 in Prince George/Disputanta, and 67 in Suffolk. Thanks to Sara Rutherford, Scott Reiter, and the Tidewater AREC entomology crew for their reports. Here is the Table.

We have evaluated over 250 moths in our 2024 vial tests, with 57% surviving the 24-hour exposure to the pyrethroid insecticide, cypermethrin, at 5 micrograms per vial.

Corn earworm/bollworm moth update–July 25, 2024

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Corn earworm (= bollworm) moth catches really started to increase this week in southeastern Virginia black light traps. The average number captured per night this week was 4 in Greensville, 11 in North Dinwiddie/Petersburg, 18 in Prince George/Disputanta, and 30 in Suffolk. Thanks to Sara Rutherford, Scott Reiter, and the Tidewater AREC entomology crew for their reports. Here is the Table

We have evaluated over 150 moths in our 2024 vial tests, with 61% surviving a 24-hour exposure to the pyrethroid insecticide, cypermethrin, at 5 micrograms per vial. Even though cypermethrin is no longer widely used, survival rates this high suggest we need to watch for some pyrethroid control failures, and to consider alternative chemistries when an insecticide is needed.

Asiatic garden beetle update–June 13, 2024

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Black light trap catches of AGB per 3 to 4 nights in Sussex County, Virginia were 500 on June 7 and 487 on June 10, 2024. Producers have reported seeing adult AGB just by kicking over the top inch or so of soil in infested areas. I heard of 5 acres of cotton in Suffolk with very heavy AGB defoliation, but there are more reports where injury is not as severe. I look forward to learning when our AGB population will finally decline.

Asiatic garden beetle update–June 6, 2024

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Captures of Asiatic garden beetle (AGB) in our black light trap climbed this past week, with 300 adults caught between May 31 and June 3, 2024. We do not know if we have reached peak emergence yet for this sporadic pest. Johnny Parker (Commonwealth Gin) reported three Virginia seedling cotton fields with AGB injury so far this season, with defoliated areas reaching 2 acres. Check for these insects under weeds such as pigweed, marestail, or volunteer soybean–focus especially on sandy soils. You may see round adult emergence holes in the ground. Or, a visit to the field at night (when adult AGB are active) may confirm the problem.

In a June 4, 2024 Pest Alert, Dr. Dominic Reisig and Dr. Guy Collins (North Carolina State University) provide AGB scouting and management information which is also applicable for Virginia cotton growers. Contact insecticides would need to be applied during peak emergence, and at night.