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.
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.
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.
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.”
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.
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.
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.
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.
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 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.
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=sharingCereal leaf beetle, a pest of small grains, overwinters as an adult.
When temperatures warm, adults migrate to small grains to lay eggs; eggs are yellow-orange in color, usually in the midvein of the leaf, and may be single or several eggs end-to-end.
I saw a few eggs at our research center field today (March 9), they were a bit darker (and stickier) than their normal color. A female may lay 50 eggs. Larvae have orange-yellow bodies with dark heads and legs, but often appear as shiny black due to the covering of mucus and fecal matter they have on their body (they look like small slugs).
Larval feeding strips leaves of phytosynthetic tissue and can cause reductions in grain quality and yield. A temperature-based model developed using Virginia and North Carolina data shows that peak egg lay occurs at approximately 182 degree-days (using January 1 as a biofix; a lower development threshold of 8℃, and an upper development threshold of 25℃). With our warm February 2023 temperatures, we hit an earlier-than-normal peak egg threshold in Suffolk, VA on March 3 (I used the Tidewater AREC WeatherSTEM as my temperature source). The larval peak follows the egg peak by an average of 17.5 days, which would be the third week of March for Suffolk. It is important to note that the model states that extremely hot or cold years may affect its accuracy. Dominic Reisig (Professor and Extension Specialist, North Carolina State University) posted that the Salisbury, NC egg peak was predicted to occur on March 5-11, but a cooler forecast may push back the larval peak to the last week of March. As of March 8, Warsaw, VA is at 123 degree-days for cereal leaf beetle and the Eastern Shore has accumulated 119 degree-days.
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. Both Virginia and North Carolina recommend an economic threshold of 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. Please refer to pages 4-44 and 4-45 of the Virginia Cooperative Extension 2023 Field Crops Pest Management Guide for additional information and spray recommendations. Another useful resource is a Journal of Integrated Pest Management article by Philips et al. (2011), Fifty Years of Cereal Leaf Beetle in the U.S.: An Update on Its Biology, Management, and Current Research.
I want to remind everyone that the Virginia Ag Expo, Virginia’s largest field day, is next Thursday, Aug 4. The Expo is an educational, marketing, and social event that farmers and agribusiness look forward to each year. It moves from one location to another each year and strives to showcase the diversity of Virginia Agriculture. Our host this year is Mill Creek Farms and the event will be located at Camden Farm, which is located near Port Royal, right off of Highway 17 in Caroline County.
Precision for Profits is the theme for the 2022 Virginia Agricultural Expo. There will be a wide variety of agribusinesses present (currently over 85 exhibitors) showcasing the latest equipment, technology, goods, and services. Virginia Cooperative Extension will be working with NRCS to highlight the diversity of soils on this farm and the high potential for precision agriculture practices. Field plots are once again a walking, go-at-your-own-pace tour designed to fit your interest and schedule. Breakfast and Lunch will be catered by the vendors shown below.
The Virginia Ag Expo is jointly sponsored by the Virginia Grain Growers and Virginia Soybean Associations, in Cooperation with Virginia Cooperative Extension.
This event is FREE to the public. Click the link below to let us know you are coming!
The upcoming weekend rainfall (our meteorologists seem assured that it’ll be widespread) should greatly help parts of Virginia that are short on or getting short of topsoil moisture and position us perfectly for a good start to the soybean growing season.
However, with the rainfall comes cooler soil temperatures. Below are predictions for 4-inch soil moisture and soil temperature over the next 10 days from Orange (one of the coolest parts of Virginia) and Suffolk (one of the warmest parts). As you see, soil temperatures will plummet from relatively warm (>60o) to nearly 50o or less over the weekend. While soybean seed will germinate and emerge in a reasonable amount of time at 60O, germination and emergence will be very slow when temperatures dip below this.
Therefore, heed my suggestion and make sure that you have a good fungicide seed treatment on anything that you are planting now or early next week.
Below is the fungicide efficacy chart from our Pest Management Guide. The main diseases that we need to concern ourselves with are Rhizoctonia and Fusarium sp. If in wet soils, Pythium and Phytophtora sp. could also be a problem with slow-emerging soybean. Be sure to protect a slow-emerging crop with a fungicide containing the active ingredients that provide good to excellent control of the appropriate disease.
Many may have already planted. Some have stopped planting other crops such and peanut and cotton due to cool soils and started planting soybean instead. Regardless, an advantage of soybean is that it tolerates a wide range of planting dates. I’ve found no advantage to planting soybean before May and have seen little yield penalty from planting as late as the first week of June, under most conditions. There are advantages to planting early and planting late, but that is not the subject of this post. Contact me for more detailed discussion on this matter-it will take more that a few comments.
With that said, I’ve always preferred May planting due to less risk of frost damage and slow emergence that is common with earlier planting. Still there are big differences in management when planting in early- versus late-May. Here I’ll review a few of these.
As always, contact me for more details regarding these tips or discuss other early-season soybean issues.