Category Archives: Crop Update

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).

Peanut Burrower Bug in Virginia peanuts

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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.

Peanut burrower bugs can cause a wide range of damage, which is not visible until after the peanuts are harvested and shelled.
Peanut burrower bug poses a complex problem for producers | Colquitt County Ag Report (uga.edu)
Peanut Burrower Bug (tamu.edu)

Soybean Fungicide Advisory – August 15, 2019

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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:

Blacksburg_soyadv_15Aug2019Download
Blackstone_soyadv_15Aug2019Download
Critz_soyadv_15Aug2019Download
Eastern-Shore_soyadv_15Aug2019Download
GladeSprg_soyadv_15Aug2019Download
Middleburg_soyadv_15Aug2019Download
Shenandoah_soyadv_15Aug2019Download
Tidewater_soyadv_15Aug2019Download
VA-Beach_soyadv_15Aug2019Download
Warsaw_soyadv_15Aug2019Download
Winchester_soyadv_15Aug2019Download

Soybean Fungicide Advisory – August 8, 2019

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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:

Blacksburg_soyadv_08Aug2019Download
Blackstone_soyadv_08Aug2019-2Download
Critz_soyadv_08Aug2019-2Download
GladeSprg_soyadv_08Aug2019-2Download
Middleburg_soyadv_08Aug2019-2Download
Painter_soyadv_08Aug2019-2Download
Shenandoah_soyadv_08Aug2019-2Download
Suffolk_soyadv_08Aug2019-2Download
VA-Beach_soyadv_08Aug2019-2Download
Warsaw_soyadv_08Aug2019-2Download
Winchester_soyadv_08Aug2019-2Download

Soybean Fungicide Advisory – August 3, 2019

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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:

Blacksburg_soyadv_03Aug2019Download
Blackstone_soyadv_03Aug2019Download
Critz_soyadv_03Aug2019Download
GladeSprg_soyadv_03Aug2019Download
Middleburg_soyadv_03Aug2019Download
Painter_soyadv_03Aug2019Download
Shenandoah_soyadv_03Aug2019Download
Suffolk_soyadv_03Aug2019Download
VA-Beach_soyadv_03Aug2019Download
Warsaw_soyadv_03Aug2019Download
Winchester_soyadv_03Aug2019Download

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

Soybean Fungicide Advisory – July 25, 2019

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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

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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).

Soybean Fungicide Advisory – July 19, 2019

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Based on research conducted since 2014, we have developed a disease favorable day threshold for predicting when a fungicide application in soybean will be economical. The favorable day threshold is based on daily average temperature and hours of high relative humidity, and these parameters are being monitored from weather stations located at Virginia Tech Agricultural Research and Extension Centers (AREC) throughout the state. We have determined that weather conditions approximately three weeks prior to the beginning pod (R3) stage of the soybean crop are the most critical for determining if disease will impact yield and if a foliar fungicide application will be economical. Fungicide recommendations for different locations throughout Virginia can be downloaded below. To use the advisory, follow these steps:

1) Identify the weather station (AREC) closest to your field. A map of the AREC locations can be found here.

2) Download the PDF for your location below.

Blacksburg_soyadv_18Jul2019

Blackstone_soyadv_18Jul2019

Critz_soyadv_18Jul2019

Glade_Spring_soyadv_18Jul2019

Middleburg_soyadv_18Jul2019

Painter_soyadv_18Jul2019

Shenandoah_soyadv_18Jul2019

Suffolk_soyadv_18Jul2019

Warsaw_soyadv_18Jul2019

Winchester_soyadv_18Jul2019

VA_Beach_soyadv_18Jul2019

3) Under the “date” column, find the date that corresponds to approximately when your soybean crop has reached or will reach the R3 (beginning pod) stage).

4) In the row that corresponds to your R3 date, determine if disease risk is low, moderate, or high based on the favorable day threshold.

5) The last column indicates if a spray is recommended based on your R3 date.

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 below.

Soybean Fungicide efficacy table_2019_final

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

 

 

Wheat Disease Update – May 9, 2019

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Fusarium head blight (FHB) risk is continuing to increase in parts of Virginia. Upcoming rain events will increase risk over the next three days (see figure below). Much of the wheat in the southern part of the state is past the vulnerable flowering stage, but wheat that is at or about to enter flowering may be at risk. Consider applying a fungicide if risk is moderate to high, especially on susceptible or moderately susceptible varieties. Fungicides should be applied at early flowering or up to one week later. Do not apply a strobilurin-containing fungicide since this can increase DON contamination. Recommended fungicides include Prosaro, Caramba, Proline, and Miravis Ace. Increased incidence and severity of leaf blotch and powdery mildew have been observed in some fields, and these fungicides will also provide control of foliar diseases.

Wheat Disease Update – April 25, 2019

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Most of the wheat crop in Virginia is currently between flag leaf emergence and heading with some wheat close to the flowering stage. Foliar diseases including powdery mildew and leaf blotch have been observed in some fields, but overall levels of disease have been low so far. As wheat reaches the flowering stage, it is susceptible to infection with Fusarium head blight (FHB), and this is the critical stage for making fungicide applications. Currently, the risk for FHB infection is low throughout Virginia. In addition, the 3-day forecast indicates risk will remain low. FHB risk can be monitored using the Fusarium Risk Assessment Tool (http://www.wheatscab.psu.edu/).
Recommended fungicides for control of FHB and DON contamination include Caramba, Prosaro, Proline, and Miravis Ace. Do not apply a strobilurin-containing fungicide after the flag leaf stage since this has the potential to increase DON concentrations in the grain. To maximize their effectiveness, fungicides for FHB and DON control should be applied at early flowering or up to one week later. Fungicides that control FHB and DON will also control foliar diseases including powdery mildew, leaf rust, stripe rust, and leaf blotch. For specific wheat disease management recommendations or assistance with disease identification, contact Dr. Hillary L. Mehl (hlmehl@vt.edu). The 2019 Fungicide Efficacy Table for Wheat can be downloaded below.

NCERA 184 Wheat fungicide table 2019_Final