Author Archives: Sean Malone

Corn earworm update for September 7, 2023

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.

Corn earworm update for August 24, 2023

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

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 for Aug. 2, 2023

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).

Cereal leaf beetle in Virginia: update for March 9, 2023

Cereal leaf beetle, a pest of small grains, overwinters as an adult.

Adult cereal leaf beetle
Cereal leaf beetle 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.

Cereal leaf beetle eggs

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).

Cereal leaf beetle larvae and characteristic skeletonized leaf feeding injury

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.

Corn earworm report for September 8, 2022

Corn earworm (=bollworm) moth captures from southeast Virginia black light traps this week were 5 per night at Templeton (Prince George Co.) and 4 per night at Disputanta (Prince George Co.); Suffolk numbers averaged 45 per night. Here is the Table. In our pyrethroid resistance monitoring tests, the seasonal average is at 33% survival (n=565 moths tested).

Corn earworm update for September 1, 2022

Corn earworm (=bollworm) moth captures from southeast Virginia black light traps this week were 7 per night at Templeton (Prince George Co.) and 9 per night at Disputanta (Prince George Co.); Suffolk numbers reached 60 per night. Here is the Table. In our pyrethroid resistance monitoring tests, the seasonal average is at 33% survival (n=502 moths tested).

Corn earworm/bollworm update for August 25, 2022

This week’s corn earworm (=bollworm) moth captures from local black light traps were: Sara Rutherford (Greensville ANR Agent) reported a nightly average of 20 moths; Scott Reiter (Prince George ANR Agent) had 8 per night at Templeton and 10 at Disputanta; the Spiers reported 5 per night in Dinwiddie; and we averaged 28 in Suffolk. Here is the Table. In our pyrethroid resistance monitoring tests, the seasonal average is at 30% survival (n=395 moths tested).

Corn earworm/bollworm update for August 11, 2022

This week’s corn earworm (=bollworm) moth captures from local black light traps were: Sara Rutherford (Greensville ANR Agent) reported a nightly average of 13 moths; Scott Reiter (Prince George ANR Agent) had 16 per night at Templeton and 19 at Disputanta; and we averaged 28 in Suffolk. Here is the Table. In our pyrethroid resistance monitoring tests, the seasonal average is at 39% survival (n=278 moths tested).