Category Archives: Pest Group

Cooler Soil Temperatures = Delayed Soybean Emergence

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.

Corn earworm/bollworm update for August 26, 2021

Captures of corn earworm (=bollworm) moths decreased this week in our black light traps. The average number of moths caught per night was: Dinwiddie = 2; Greensville = 6; Prince George-Templeton = 1; Prince George-Disputanta = 2; Suffolk = 13. Here is the Table. In our unsprayed, conventional (non-Bt) cotton plots at the Tidewater Agricultural Research and Extension Center in Suffolk, we had 11% boll injury due to bollworm feeding this week. Adult cypermethrin (pyrethroid insecticide) vial tests have 29% moth survival with 796 moths tested in 2021.

Corn earworm update for August 12, 2021

Corn earworm (=bollworm) moth catches continued to increase this week in our black light traps. The average number of moths caught per night was: Greensville = 10; Prince George-Templeton = 26 (Scott Reiter reported this trap is next to some early April-planted corn that the shucks are starting to dry down on); Prince George-Disputanta = 6; Southampton = 10; Suffolk = 27. Here is the Table. We found bollworm eggs in cotton in Greensville and Suffolk this week. The 2021 season average in our adult cypermethrin vial tests is 25% survival (562 moths tested).

Corn earworm moth report for July 29, 2021

Black light trap captures of corn earworm moths (average number per night) in southeast Virginia this week were: Prince George-Templeton=0.7; Prince George-Disputanta=0.9; Southampton=2.0; Suffolk=4.0.

Our pyrethroid (cypermethrin @ 5 micrograms per vial rate) vial tests currently have 14% of corn earworm moths surviving the 24-hour exposure period (n=243 moths tested).

Pest Alert: Cyclamen mites in Chesapeake strawberries

In the past weeks, a few strawberry growers have expressed their concern about the possibility of cyclamen mite infestations. After visiting some strawberry farms in the Chesapeake area this week, I found symptoms of cyclamen mite damage in a few fields. Because of the small size of the mites, I took leaf samples from the symptomatic plants and confirmed the presence of the mites in the laboratory.

The cyclamen mite is a serious pest of strawberries. It has been reported in most strawberry-producing states. Cyclamen mites are tiny mites (0.001 in long) that feed on the tissue of nonexpanded and newly unfolded leaves in the strawberry plants. Adults and immatures of the cyclamen mite are considerably smaller than two-spotted spider mites and cannot be easily seen with the naked or a hand lens. Symptoms of cyclamen mite infestation include severely crumpled and crinkled leaves, as well as stunted plants.

The presence of cyclamen mites was confirmed mostly on ‘Ruby June’ strawberries, but they can infest any strawberry cultivar. Strawberry growers in the Virginia Beach metropolitan area and the eastern shore should beware of the presence of this pest mite in their field. There are very few miticides available for the control of cyclamen mites. Unfortunately, the same products used for the control of two-spotted spider mites do not always provide control for cyclamen mites. The best performing product against this pest is Portal (fenpyroximate). Agri-mek (abamectin), is also labeled for cyclamen mites. Despite being miticides, Acramite and Magister are not labeled for control of cyclamen mite and may not provide enough protection against it.

Dr. Lorena Lopez
Department of Entomology
Virginia Tech | Eastern Shore Agricultural Research and Extension Center (ESAREC)
(954) 529 9042 | lorelopezq257@vt.edu

Corn earworm report–September 24, 2020

Corn earworm moth black light trap catches were low this week, averaging from 2 to 6 per night (Greensville=3; Hanover=2; Southampton=6; Suffolk=2). Most trap operators will be shutting off their traps by the end of this month. We greatly appreciate the efforts of cooperating growers, Virginia Cooperative Extension Agents Mike Parrish, Sara Rutherford, Laura Maxey-Nay, Scott Reiter, and Josh Holland, and Tidewater Agricultural Research and Extension Center’s Daniel Espinosa. TABLE

Corn earworm report–Sep. 10, 2020

Average nightly corn earworm/bollworm moth black light trap captures for this week were: Greensville=28; Prince George-Templeton=5.5; Prince George-Disputanta=7; Southampton=17; Suffolk=76. Here is the Table

For soybean, here is the tool that calculates the corn earworm larval threshold number based on user input values for sampling techinque (sweep net or beat cloth), cost of insecticide application, price of beans, and row width: threshold calculator

We have done 391 vial tests so far this season, with 35% of moths surviving the 24-hour exposure to the pyrethroid cypermethrin at the rate of 5 micrograms per vial.