Category Archives: Disease

2020 Four Rivers Agricultural Conference – Providence Forge, VA

The 2020 Four Rivers Agricultural Conference will be held Tuesday, Jan. 14 at Providence Forge Recreation Center: 9900 Carriage Rd, Providence Forge, 23140. This year’s conference will include pesticide certification training, several Specialists and Agents from Virginia Cooperative Extension that will cover a wide variety of topics, and others. In addition, you will be able to get your dicamba herbicide certification with training being offered by Don Cline of BASF. We look forward to seeing your there for a great day of learning and interaction with the experts. Lunch will be provided. Agenda detail are below.

Full Attendance to the conference has been approved for Private Pesticide Applicator Recertification in Category 90 and Commercial Categories 1A, 10, and 60.  The conference has also been approved for 2.5 Virginia Nutrient Management CEU and 2.0 Contact hours for DCR Conservation Planner Re-Certification

9:00        Registration Opens/Meet with Vendors

9:30        Welcome

9:35        Controlling your Drops highlighting dicamba and glyphosate– Laura Maxey-Nay, Hanover Ag Agent

10:00     Pesticide Training – droplet size/playdough- Ed Olsen, Henrico Ag Agent

10:30     Pesticide Legal Update – Robert Christian, VDACS

11:00     2nd round of registration for those not needing pesticide recertification credit

11:15     Dicamba Certification – Don Cline, BASF

12:15     Sponsored Lunch/Meet with Vendors

1:00        Agency updates

1:15        Grain Market Update- Robert Harper, Manager, Virginia Farm Bureau Grain Division

1:45        What I learned from Argentina Agriculture, pest control and nutrient management –Paul Davis

2:05        Corn Update and Hybrid Selection, Dr. Wade Thomason, Extension Grain Agronomist

2:35        Break (visit with sponsors)

2:50        Positioning Your Full-Season Soybean for Maximum Yields, Dr. David Holshouser, Extension Soybean Agronomist

3:20        Making insect management decisions now by purchasing seed for next season, Sally Taylor, Extension Grain Entomologist

3:50       Nematode Panel, various specialists will discuss current nematode control practices.

4:50       Adjourn and paperwork

Tri-County Crop Production Conference – Carson, VA

The 2020 Tri-County Crop Production Conference will be held Tuesday, Jan. 14 at the Carson Volunteer Fire Department on 19806 Halifax Rd in Carson, VA. This year’s conference will host several Specialists from Virginia Tech that will cover a wide variety of topics. In addition, you will be able to get your dicamba herbicide certification with training being offered by Don Cline of BASF. We look forward to seeing your there for a great day of learning and interaction with the experts. Lunch will be provided. Agenda detail are below.

9:00 – 9:05          Welcome and Announcements

9:05 – 9:40         Positioning Your Full-Season Soybean for Maximum Yields– Dr. David Holshouser

There are many things we can do to increase full-season soybean yield, but decisions made before planting are the most important.  This presentation will focus on site-specifically positioning your crop to best take advantage of the limiting resources of water, light, and nutrients.

9:40-10:20          Plant disease management – Dr. David Langston

Nematode and disease interaction issues in soybeans.  Update on fungicide and seed treatments available for corn and soybeans.  Common diseases occurring in 2019.

10:20-10:40       Break

10:40 – 11:10    Update on insect pest management – Dr. Sally Taylor

Review of major insect pests in 2019.  Recommendations for preparing for 2020, scouting tips to use throughout the season, and updates on insecticides available for use.

11:10 – 11:40   Small Grain and Corn Update – Dr. Wade Thomason

Review of the latest research in corn and small grain production in Virginia. 

11:40 – 12:00     Getting Started with Irrigation and Irrigation Survey – Dr. Julie Shortridge

Irrigation is not used on a wide scale in Virginia.  This presentation will introduce our new water specialist and a irrigation survey for growers.

12:00 -12:45       Lunch

12:45 – 1:15       Pesticides in VA update – Robert Christian, VDACS

Update on federal record keeping and worker protection standard. Additional information on changes in pesticide labeling for VA.  PPE review for commonly used pesticides.  Changes to paraquat labeling, handling, and training.

1:15 – 1:35         Weed control update – Scott Reiter

Roundup resistant common ragweed is common in our soybean cropping systems.  There are also 4 different herbicide technology systems in play for the 2020 season.  We will cover the options available and the stewardship needed to keep the herbicides on the target crops.

1:35 – 1:55          Cover crops – Mike Parrish

Cover crops have many uses in our production systems.  Soil erosion control, soil health properties, weed control, and moisture retention.  Presentation will cover results from local cover crop plots and impact on these properties.

1:55 – 3:00          On Target Academy – Don Cline, BASF

This session will cover the required training for using dicamba herbicide in post-emerge applications to Xtend soybeans and cotton.  Applicator & recordkeeping requirements, nozzle selection and technology, buffer requirements, weather conditions, and tank mix additives will be explained in detail

Full Attendance to the conference has been approved for Private Pesticide Applicator Recertification in Commercial Categories 1A, 10, and 60. 

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:

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).

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).

Soybean Fungicide Advisory – July 19, 2019

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

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 – May 1, 2019

There is increased risk of Fusarium head blight (FHB) in some parts of Virginia, especially near the Northern Neck and Eastern Shore of Virginia. Wheat in much of the state is flowering, and if a field is in a high risk area a fungicide application is recommended. 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.

Wheat varieties vary in susceptibility to FHB and DON, and this should be considered when making decisions of whether or not to apply a fungicide at flowering for FHB control. The FHB Risk Tool (http://www.wheatscab.psu.edu/) allows you to select the susceptibility of your wheat variety to determine risk. You can find information on FHB susceptibility of your wheat variety from your seed dealer or in the Virginia Cooperative Extension Small Grains publication. The FHB Risk algorithm adjusts the relative risk based on the variety susceptibility as illustrated below. For assistance with small grains disease identification or for additional management recommendations contact Dr. Hillary Mehl, Extension Plant Pathologist (hlmehl@vt.edu).

FHB risk for susceptible (S) wheat, May 1, 2019.

FHB risk for moderately resistant (MR) wheat, May 1, 2019.