Category Archives: Pest Group

Corn earworm update for September 5, 2019

Average nightly black light trap captures of corn earworm moths this week were: Chesapeake=33; Greensville=13; Southampton=10; Suffolk=27. Hanover had 12 per night if averaged over the past 2 nights, but 3 if averaged over the entire week. Here is the table:

In our corn earworm pyrethroid resistance monitoring experiment (adult vial tests), the seasonal average is 36% survival to a 24-hour exposure of 5 micrograms of cypermethrin per vial.

Corn earworm update for August 29, 2019

Nightly corn earworm/bollworm moth averages for reporting black light trap stations this week were: Greensville=22; Prince George (Templeton)=12; Prince George (Disputanta)=10; Southampton=13; Suffolk=32. Please see the link to the table below and also compare this year’s Suffolk, VA numbers to the past several years.

I have seen a large number of corn earworm moths in our soybean at the Tidewater Agricultural Research & Extension Center in Suffolk this week. Remember to scout for larvae and use the threshold calculator for soybean: https://www.ces.ncsu.edu/wp-content/uploads/2017/08/CEW-calculator-v0.006.html

Our pheromone trap catches at Suffolk have also increased and we were able to conduct more adult vial tests for resistance monitoring using the pyrethroid cypermethrin. The average survival for this season is now 37%.

Soybean Fungicide Advisory – August 15, 2019

For soybean that is at or near the beginning pod (R3) stage, it is time to consider whether or not a fungicide application is needed to control foliar diseases and protect yield. Most of the soybean in Virginia is past the beginning pod (R3) stage, and fungicide applications are more likely to be profitable when applied at or near R3/R4. The Virginia soybean fungicide advisory indicates that disease risk is variable across the state. Fields with moderate risk should be scouted since foliar diseases will not be an issue in every field every year.  Keep in mind that other risk factors also contribute to disease severity and yield loss to fungal diseases. High risk fields include those where susceptible soybean varieties are planted, there is a recent history of soybean foliar diseases, and/or rotations out of soybean are short or soybean is planted continuously over several years. Foliar fungicides are ineffective for control of most stem and root diseases. If based on the soybean fungicide advisory or other factors you decide to apply a fungicide, applications are generally the most effective when applied between R3 and R4 stages (no later than R5). The most recent Soybean Fungicide Efficacy Table can be downloaded from the Crop Protection Network website. Instructions on how to use the Virginia soybean fungicide advisory can be found in the July 19 blog post. A summary of disease risk and spray recommendations for different locations in Virginia can be found below. If you have any questions, contact Dr. Hillary Mehl (hlmehl@vt.edu).

Region of VirginiaLocation of weather stationSoybean disease riskRecommendation
Eastern ShorePainterHighSpray
SoutheasternSuffolkModerateScout
SoutheasternVirginia BeachHighSpray
Northern NeckWarsawHighSpray
CentralBlackstone ModerateScout
NorthernMiddleburgModerateScout
NorthernShenandoahModerateScout
NorthernWinchesterLowDon’t spray
WesternCritzHighSpray
WesternBlacksburgHighSpray
WesternGlade SpringHighSpray

For detailed daily advisories, select the location closest to your field and download the corresponding file here:

Soybean Fungicide Advisory – August 8, 2019

For soybean that is at or near the beginning pod (R3) stage, it is time to consider whether or not a fungicide application is needed to control foliar diseases and protect yield. The Virginia soybean fungicide advisory indicates that disease risk is variable across the state. Fields with moderate risk should be scouted since foliar diseases will not be an issue in every field every year.  Keep in mind that other risk factors also contribute to disease severity and yield loss to fungal diseases. High risk fields include those where susceptible soybean varieties are planted, there is a recent history of soybean foliar diseases, and/or rotations out of soybean are short or soybean is planted continuously over several years. If based on the soybean fungicide advisory or other factors you decide to apply a fungicide, applications are generally the most effective when applied between R3 and R4 stages (no later than R5). The most recent Soybean Fungicide Efficacy Table can be downloaded from the Crop Protection Network website. Instructions on how to use the Virginia soybean fungicide advisory can be found in the July 19 blog post. A summary of disease risk and spray recommendations for different locations in Virginia can be found below.

Region of VirginiaLocation of weather stationSoybean disease riskRecommendation
Eastern ShorePainterHighSpray
SoutheasternSuffolkModerateScout
SoutheasternVirginia BeachModerate to highScout
Northern NeckWarsawModerate to highScout
CentralBlackstone ModerateScout
NorthernMiddleburgModerate to highScout
NorthernShenandoahHighSpray
NorthernWinchesterLowDon’t spray
WesternCritzHighSpray
WesternBlacksburgLowDon’t spray
WesternGlade SpringHighSpray

For detailed daily advisories, select the location closest to your field and download the corresponding file here:

Corn earworm update for August 8, 2019

Black light trap catches of H. zea (corn earworm/bollworm) moths increased at most locations this week. Please see the data table for more information.

We have tested 168 corn earworm moths in our cypermethrin vial tests so far this season, with a seasonal average of 39.5% survival. Here are the results by month (we’ll be conducting more tests throughout August):

We have updated our corn earworm survey of field corn (as a predictor of infestation risk in other crops such as soybean) to include Rockingham County’s 10.8% infested ears. Thanks to all cooperators for their efforts. Statewide average infested ears was 15.3% for 2019. The updated table and map are here:

Soybean Fungicide Advisory – August 3, 2019

For soybean that is at or near the beginning pod (R3) stage, it is time to consider whether or not a fungicide application is needed to control foliar diseases and protect yield. The Virginia soybean fungicide advisory indicates that disease risk is variable across the state. Fields with moderate risk should be scouted since foliar diseases will not be an issue in every field every year.  Keep in mind that other risk factors also contribute to disease severity and yield loss to fungal diseases. High risk fields include those where susceptible soybean varieties are planted, there is a recent history of soybean foliar diseases, and/or rotations out of soybean are short or soybean is planted continuously over several years. If based on the soybean fungicide advisory or other factors you decide to apply a fungicide, applications are generally the most effective when applied between R3 and R4 stages (no later than R5). The most recent Soybean Fungicide Efficacy Table can be downloaded from the Crop Protection Network website. Instructions on how to use the Virginia soybean fungicide advisory can be found in the July 19 blog post. A summary of disease risk and spray recommendations for different locations in Virginia can be found below.

Region of VirginiaLocation of weather stationSoybean disease riskRecommendation
Eastern ShorePainterHighSpray
SoutheasternSuffolkLow to moderateDon’t spray
SoutheasternVirginia BeachModerateScout
Northern NeckWarsawModerate to highScout
CentralBlackstone LowDon’t spray
NorthernMiddleburgModerate to highScout
NorthernShenandoahModerate to highScout
NorthernWinchesterLow to moderateDon’t spray
WesternCritzHighSpray
WesternBlacksburgModerateScout
WesternGlade SpringHighSpray

For detailed daily advisories, select the location closest to your field and download the corresponding file here:

If you have any questions, feel free to contact Dr. Hillary Mehl (hlmehl@vt.edu).

Corn earworm update, including field corn survey results, for August 1, 2019

Corn earworm moth catches are increasing for most black light stations; nightly averages this week were: Greensville=25.1; Prince George (Templeton)=5.7; Prince George (Disputanta)=3.7; Warsaw=46.4; Southampton=9.0; Suffolk=14.6.

Preliminary results from our annual survey of field corn show the following percent infested ears (based on sampling 5 corn fields/county, 50 ears per field, for evidence of corn earworm larvae): Accomack=16.0 percent infested ears; Amelia=15.6; Chesapeake=5.6; Dinwiddie=19.6; Essex=11.6; Greensville=32.8; Hanover=32.8; Isle of Wight=17.6; King & Queen=13.6; King William=24.4; Lancaster=4.8; Northampton=11.2; Northumberland=4.0; Prince George=12.8; Southampton=11.2; Virginia Beach=17.6; Westmoreland=12.8. Thanks to the following for collecting data from their counties: Eastern Shore AREC entomology; Laura Siegle; Watson Lawrence; Mike Parrish; Robbie Longest and Brittany Semko; Sara Rutherford; Laura Maxey-Nay; Livvy Preisser; Trent Jones; Scott Reiter; Joshua Holland; Roy, Bailey, and Fletcher Flanagan; and Stephanie Romelczyk and Amerah Thompson.

We have found bollworm eggs and small larvae in our cotton experiment in Suffolk. Please be sure to scout your fields.

Soybean Fungicide Advisory – July 25, 2019

For soybean that is at or near the beginning pod (R3) stage, it is time to consider whether or not a fungicide application is needed to control foliar diseases and protect yield. The Virginia soybean fungicide advisory indicates that disease risk is moderate to high in most locations. Fields with moderate risk should be scouted since foliar diseases will not be an issue in every field every year.  Keep in mind that other risk factors also contribute to disease severity and yield loss to fungal diseases. High risk fields include those where susceptible soybean varieties are planted, there is a recent history of soybean foliar diseases, and/or rotations out of soybean are short or soybean is planted continuously over several years. If based on the soybean fungicide advisory or other factors you decide to apply a fungicide, applications are generally the most effective when applied between R3 and R4 stages (no later than R5). The most recent Soybean Fungicide Efficacy Table and instructions on how to use the Virginia soybean fungicide advisory can be found in last week’s blog post. A summary of disease risk and spray recommendations for different locations in Virginia can be found below.

Region of Virginia Location of weather station Soybean disease risk Recommendation
Eastern Shore Painter High Spray
Southeastern Suffolk Moderate Scout
Southeastern Virginia Beach Moderate Scout
Northern Neck Warsaw Moderate to high Scout
Central Blackstone Low to moderate Don’t spray
Northern Middleburg Moderate to high Scout
Northern Shenandoah High Spray
Northern Winchester Moderate Scout
Western Critz High Spray
Western Blacksburg High Spray
Western Glade Spring High Spray

For detailed daily advisories, select the location closest to your field and download the corresponding file here:

Glade_Spring_soyadv_25Jul2019

Middleburg_soyadv_25Jul2019

Painter_soyadv_25Jul2019

Shenandoah_soyadv_25Jul2019

Suffolk_soyadv_25Jul2019

VA_Beach_soyadv_25Jul2019

Warsaw_soyadv_25Jul2019

Winchester_soyadv_25Jul2019

Blacksburg_soyadv_25Jul2019

Blackstone_soyadv_25Jul2019

Critz_soyadv_25Jul2019

If you have any questions, feel free to contact Dr. Hillary Mehl (hlmehl@vt.edu).

Peanut Disease Update – July 25, 2019

As August approaches, now is the time to be scouting peanuts for leaf spot and soilborne diseases and making timely fungicide applications. Calendar-based or advisory-based spray programs can be followed, but be sure to make your fungicide applications before rainy weather makes it difficult to get into fields. Many of our leaf spot outbreaks over the past couple of years were due to extended periods of rainfall and delayed fungicide applications. Cooler, wet weather over the past several days has increased the risk for Sclerotinia blight. In our research plots at the Tidewater AREC, we found small amounts of late leaf spot, Sclerotinia blight, and southern stem rot this week. The leaf spot and Sclerotinia blight advisories, which  can be found on the Peanut Cotton Infonet website, indicate disease risk is currently high. For fungicide recommendations, contact your county extension agent or Dr. Hillary Mehl (hlmehl@vt.edu).