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Sweet corn sampling across Virginia – Moth Catch for Week of Aug 6-10

 

 

 

 

Corn earworm larva developing fine on Bt sweet corn in Page County, VA.  Photo by Kenner Love, VCE.

Sweet corn farms are being monitored around Virginia for corn earworm and fall armyworm.  Moth Trap Catch Data are being recorded by:  Katlyn Catron  (Montgomery Co.); Jason Cooper (Rockingham Co.); Ursula Deitch (Northampton Co.); Helene Doughty (Accomack Co. & Virginia Beach); Kenner Love (Rappahannock Co.); Laura Maxey Nay (Hanover Co.); Steve Pottorff (Carrol Co.); Stephanie Romelczyk  (Westmoreland Co.); Laura Siegle (Amelia Co.); Rebekah Slabach (Halifax Co.); and Mark Sutphin (Frederick Co.).

Male corn earworm moth on Heliothis Trap.

This week we observed a general increase in corn earworm moth catch at many locations, to warrant frequent spraying.  Some of the areas with the highest CEW activity were on the Eastern Shore, Virginia Beach, Frederick Co., Montgomery Co. and Hanover Co.   We still have not seen very many  fall armyworm moths yet. For corn earworm, moth trap catch of less than 1 per night means  low pest pressure and sweet corn sprays can probably be spaced 5-6 days apart during silking.  However, a catch of >1 or >13 moths per night means moderate and high pest pressure, respectively, and a more frequent spray interval (every 3 or 2 days) is justified.  Here are the trap catch results (moths per night) for several locations around Virginia for this week (note we do not have data for all locations):

Week of Aug 6 (avg)
Region County Field CEW/night FAW/night
Eastern Shore Accomack ESAREC – cemetery 6.0 NA
Eastern Shore Accomack ESAREC – woods 0.2 NA
Eastern Shore Accomack ESAREC – sweet corn 18.6 0.9
Eastern Shore Northampton Bridge Tunnel 18.3 NA
Eastern Shore Northampton Capeville 1 1.0 0
Eastern Shore Northampton Cape charles 3.0 NA
Eastern Shore Northampton Eastville 2.7 1.8
Eastern Shore Northampton Nassawaddox 0.3 0.3
Virginia Beach Virginia Beach Pungo 1 6.2 0.9
Piedmont Amelia Field 1 NA NA
Piedmont Hanover Farm 1 6.3 0.0
Piedmont Hanover Haynes NA NA
Northern Neck Westmoreland Field 1 NA NA
Northern Neck Westmoreland Field 2 NA NA
Shenandoah Valley Rappahannock Field 1 0.6 0.1
Shenandoah Valley Page Field 1 0.2 0.1
Shenandoah Valley Frederick Farm 1 6.1 0
Shenandoah Valley Frederick Farm 2 28.3 NA
Shenandoah Valley Rockingham Farm 1 3.4 NA
Shenandoah Valley Rockingham Farm 2 NA NA
New River Valley Montgomery KC 1.3 0
New River Valley Montgomery KO1 18.0 0
New River Valley Montgomery KO2 28.3 0
New River Valley Montgomery WF1 6.8 NA
New River Valley Montgomery WF2 1.3 NA
New River Valley Montgomery WF3 6.7 NA
New River Valley Montgomery WS1 8.8 NA
New River Valley Montgomery WS2 0.0 NA
New River Valley Montgomery WS3 4.5 NA
Southwest Carroll 0.3 0.5

Midsummer peanut updates for Virginia

According with the FSA, 26,323 acres of peanut were planted this year in Virginia; and the crop progresses well so far. The early May planted peanuts are getting close to the full seed growth stage (two pictures of peanut pods and seed are provided here)

Peanut pod and seed at full seed stage.

Peanut plants and pods on Aug-7-17 and planted in early May.

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However, in some sandy fields plants have become yellowish lately. It is difficult to guess the reason for the yellow color. It could be caused by poor inoculation or nitrogen fixing due to drought or water standing; manganese deficiency, which is relatively easy to identify (a picture of manganese deficiency is provided here)

Peanut leaves with manganese deficiency.

; but also acidic soils, which are predominant in south-eastern Virginia. Soil pH directly affects plant growth through its effects on the availability of all nutrients. For example, soils with pH less than 6 may become deficient in calcium, magnesium, phosphorus, potassium, and molybdenum. Molybdenum is essential in biological nitrogen fixation and, even though the nodule numbers may seem sufficient, the result, tissue nitrogen content, may be limited.  Gypsum does not alter soil pH; only lime can be used for that, and dolomitic limestone is the desired product as it provides calcium and magnesium. The traditional recommended pH range for peanut land is 5.8 to 6.2, but more towards 6.2 when Virginia-type peanuts are planted. In addition, limestone moves very slowly into the soil, therefore applying limestone early in the planting process and tilling it into the root zone (top 7 inches) is important. Rainfall amount, application of fertilizers containing ammonium or urea, sulfur containing ingredients, and decomposition of organic matter (previous crop residue) also adds to soil acidity. Soil sampling should be taken in the fall and, if the test results indicate a need for limestone, for best results it should be applied in the fall or winter months. If applied just prior to planting and soil is dry, lime will have little effect on the pH.

Going back to the yellow plant color, the best approach for knowing and not just guessing what causes it is to take soil and tissue samples and send to a laboratory for determining the soil pH and tissue nutrient content. The table below shows the sufficiency levels for macro and micronutrients of the peanut vines. It is recommended that 50 whole shoots throughout the field, or problematic areas, should be combined in one sample prior to or at bloom stage.

Macronutrients

%

Micronutrients

ppm

Nitrogen (N) 3.50-4.50 Iron (Fe) 60-300
Phosphorus (P) 0.25-0.50 Manganese (Mn) 60-350
Potassium (K) 1.70-3.00 Boron (B) 25-60
Calcium (Ca) 1.25-2.00 Copper (Cu) 5-20
Magnesium (Mg) 0.30-0.80 Zinc (Zn) 25-60
Sulfur (S) 0.20-0.35 Molybdenum (Mo) 0.10-5.00

 

Manganese (1 pound per acre) and boron (up to 0.5 pounds per acre) are regular applications in peanut production during summer, but nitrogen can also be applied if the tissue analysis indicates the need. Rate of 60 to 120 pounds per acre elemental nitrogen (or 285 to 571 pounds per acre of ammonium sulfate) can be applied, depending on the test results; and it is worth applying even at this time (August). After all, there are two more months of peanut growth. Increasingly more fields seem to require potash applications. Peanut is efficient at scavenging phosphorus and potassium left in the soil from previous crops, but for some reason potassium is getting slim each year. An application of 100 pounds per acre of potash may correct that deficiency.

Knowing the history of each field for yield and crop growth, can help to anticipate where nutritional problems may occur and allow for preventive measures even before symptoms are visible. Drone technology can be used to derive soil maps for pH, moisture and yield of each crop in rotation, so that precise locations within a field where problematic spots exist can be known and independently managed using the variable rate technology (VRT). The VRT consists of a control system on an application equipment, planters, sprayers, and spreaders, which allows grower to achieve site-specific application rates of inputs. To work, prescription maps need to be generated and uploaded to the computer within the machine cab that has the VRT. Drones can be used to generated these maps. For example, the last picture in this story shows an image of the soil moisture distribution of a field at the Tidewater AREC. The image was taken before peanut planting with an infra-red camera on a drone; the drone purchased not long ago with funding from the Virginia Peanut Board, the shellers, and Virginia Crop Improvement Association. In the image, the darker the blue the more soil water was available; green color indicated dryer soil sections with the driest spots being colored in yellow and red and located in the patches adjacent to the field.

Pre-plant field image taken with an infra-red camera from a drone showing soil moisture distribution.

Potential applications of this technology can help growers to use variable seeding rates and depths depending on the available soil moisture at planting, and monitor irrigation needs throughout the growing season.

Sweet corn sampling in VA – Moth trap counts for week of July 31

Corn earworm larva in Bt sweet corn in Page County, VA. Photo by Kenner Love, VCE.

Sweet corn farms are being monitored around Virginia for corn earworm and fall armyworm.  Moth Trap Catch Data are being recorded by:  Katlyn Catron  (Montgomery Co.); Jason Cooper (Rockingham Co.); Ursula Deitch (Northampton Co.); Helene Doughty (Accomack Co. & Virginia Beach); Kenner Love (Rappahannock Co.); Laura Maxey Nay (Hanover Co.); Steve Pottorff (Carrol Co.); Stephanie Romelczyk  (Westmoreland Co.); Laura Siegle (Amelia Co.); Rebekah Slabach (Halifax Co.); and Mark Sutphin (Frederick Co.).

This week we observed a general drop off in corn earworm moth catch at many locations, but still enough moth flight activity to warrant frequent spraying in many locations such as the Bridge Tunnel in Northampton County, Virginia Beach, Frederick Co., and Hanover Co.   We still have not seen very many  fall armyworm moths yet. For corn earworm, moth trap catch of less than 1 per night means  low pest pressure and sweet corn sprays can probably be spaced 5-6 days apart during silking.  However, a catch of >1 or >13 moths per night means moderate and high pest pressure, respectively, and a more frequent spray interval (every 3 or 2 days) is justified.  Here are the trap catch results (moths per night) for several locations around Virginia for this week (note we do not have data for all locations):

Week of July 31 (avg)
Region County Field CEW/night FAW/night
Eastern Shore Accomack ESAREC – cemetery 6.3 0.1
Eastern Shore Accomack ESAREC – woods 0.0 NA
Eastern Shore Accomack ESAREC – sweet corn 1.1 0.1
Eastern Shore Northampton Bridge Tunnel 15.1 NA
Eastern Shore Northampton Capeville 1 0.6 0
Eastern Shore Northampton Cape charles 2.4 NA
Eastern Shore Northampton Eastville 2.3 1
Eastern Shore Northampton Nassawaddox 0.4 1
Virginia Beach Virginia Beach Pungo 1 11.6 0.3
Piedmont Amelia Field 1 NA NA
Piedmont Hanover Farm 1 7.8 0.0
Piedmont Hanover Haynes 6.9 0.0
Northern Neck Westmoreland Field 1 3.0 0
Northern Neck Westmoreland Field 2 NA NA
Shenandoah Valley Rappahannock Field 1 0.6 0.1
Shenandoah Valley Page Field 1 0.2 0.1
Shenandoah Valley Frederick Farm 1 1.4 0.9
Shenandoah Valley Frederick Farm 2 9.1 NA
Shenandoah Valley Rockingham Farm 1 NA NA
Shenandoah Valley Rockingham Farm 2 NA NA
New River Valley Montgomery KC 0.1 0
New River Valley Montgomery KO1 3.0 0
New River Valley Montgomery KO2 1.7 0
New River Valley Montgomery WF1 2.9 NA
New River Valley Montgomery WF2 1.1 NA
New River Valley Montgomery WF3 2.0 NA
New River Valley Montgomery WS1 2.3 NA
New River Valley Montgomery WS2 2.0 NA
New River Valley Montgomery WS3 1.7 NA

 

Sweet corn moth trap numbers for VA counties – week of July 24, 2017

Sweet corn farms are being monitored around Virginia for the two most important pests attacking the ears, corn earworm and fall armyworm.  Moth Trap Catch Data are being recorded by:  Katlyn Catron  (Montgomery Co.); Jason Cooper (Rockingham Co.); Ursula Deitch (Northampton Co.); Helene Doughty (Accomack Co. & Virginia Beach); Kenner Love (Rappahannock Co.); Laura Maxey Nay (Hanover Co.); Steve Pottorff (Carrol Co.); Stephanie Romelczyk  (Westmoreland Co.); Laura Siegle (Amelia Co.); Rebekah Slabach (Halifax Co.); and Mark Sutphin (Frederick Co.).

This week we observed some big jumps in corn earworm moth catch at some locations such as the Bridge Tunnel in Northampton County, the ESAREC in Accomack Co., and Hanover Co.   We still have not seen very many  fall armyworm moths yet, only a few moths here and there in VA. For corn earworm, moth trap catch of less than 1 per night means  low pest pressure and sweet corn sprays can probably be spaced 5-6 days apart during silking.  However, a catch of >1 or >13 moths per night means moderate and high pest pressure, respectively, and a more frequent spray interval (every 3 or 2 days) is justified.  Here are the trap catch results (moths per night) for several locations around Virginia for this week (note we do not have data for all locations):

Week of July 24 (avg)
Region County Field CEW/night FAW/night
Eastern Shore Accomack ESAREC – cemetery 9.6 1
Eastern Shore Accomack ESAREC – woods 3.4 0
Eastern Shore Accomack ESAREC – sweet corn 4.6 0
Eastern Shore Northampton Bridge Tunnel 60.4 NA
Eastern Shore Northampton Capeville 1 2.1 0
Eastern Shore Northampton Cape charles 6.3 NA
Eastern Shore Northampton Eastville 10.6 1
Eastern Shore Northampton Nassawaddox 0.1 1
Virginia Beach Virginia Beach Pungo 1 11.9 1
Piedmont Amelia Field 1 NA NA
Piedmont Hanover Farm 1 11.0 0.0
Piedmont Hanover Haynes 3.9 0.0
Northern Neck Westmoreland Field 1 6.3 0
Northern Neck Westmoreland Field 2 NA NA
Shenandoah Valley Rappahannock Field 1 0.6 0
Shenandoah Valley Page Field 1 1.7 0
Shenandoah Valley Frederick Farm 1 1.4 1
Shenandoah Valley Frederick Farm 2 5.2 0
Shenandoah Valley Rockingham Farm 1 0.7 1
Shenandoah Valley Rockingham Farm 2 NA NA
New River Valley Montgomery KC 0.0 0
New River Valley Montgomery KO1 2.0 1
New River Valley Montgomery KO2 6.0 1
New River Valley Montgomery WF1 1.0 NA
New River Valley Montgomery WF2 0.0 NA
New River Valley Montgomery WF3 4.0 NA
New River Valley Montgomery WS1 0.0 NA
New River Valley Montgomery WS2 1.0 NA
New River Valley Montgomery WS3 1.0 NA

This project is sponsored by a Specialty Crop Block Grant by VDACS.

Large bollworm flight this year into VA cotton

If blacklight traps at the Tidewater AREC in Suffolk are any indication, we are currently experiencing an unusually large and early bollworm (aka corn earworm) moth flight this year. Average trap catches over the past 4 nights have averaged 70 moths per night. I have included 2016 season-long catches below for comparison.

We have additionally scouted for, and found, eggs in cotton and on silks of late-planted corn. I have included pictures below to help with identification. Our ongoing corn earworm survey has revealed large numbers of worms completing development on Bt corn in multiple counties. I strongly encourage cotton growers who planted Widestrike or Bollgard II this year to be vigilant when scouting fields. In agreement with Dominic Reisig’s (North Carolina State University) 2016 recommendations, entomologists in the Mid-South (Angus Catchot – Mississippi State University) have suggested egg thresholds broken-down by trait package:

WideStrike Cotton: Treat on 10-15% egg lays on bloom tags

BG2 cotton: Treat on 25-30% egg lay on bloom tags.

These thresholds are supported by observations made across the Southeast last year, including in North Carolina and Virginia, that worms have a higher chance of surviving on blooms than on any other part of the plant. These thresholds have not been established through experimentation and I consider them to be extra protective. Budworm eggs are identical to bollworm eggs and this species is controlled by Bt toxins. I have seen both budworm and bollworm moths in cotton this year.

Some growers have planted conventional cotton this year. We have established egg and larval thresholds in Virginia for non-Bt varities:

Eggs: 10 eggs per 100 terminals or 2 eggs per 100 fruiting forms (most cotton we have scouted has reached this threshold)

Larvae: 3 live worms per 100 terminals or 3% damage to squares, blooms, bolls

Currently, we have experienced no unexpected injury to Widestrike III or TwinLink technologies. I would not assume these varieties to be bulletproof in a high pressure year, but I do think that these technologies offer good protection in our area.

I recommend spending the extra money on a worm-specific product instead of relying on pyrethroids. Vial tests in Suffolk have indicated a trend towards resistance for several years and there have been field failures reported south of us this season. Besiege and Prevathon are good choices because they offer residual control. Besiege targets sucking-bug pests in addition to worms. I have had inquiries about Intrepid Edge. Virginia Tech has not tested this product in cotton. It has performed well in soybean tests and in cotton tests in other regions (Jeremy Greene- Clemson University, South Carolina). Keep in mind that no product works well against large larvae. Due to the early nature of this year’s flight, we may experience additional pressure later this season. I will keep you updated on what’s happening in Virginia. Please call if you have anything to report.

Sally 919-801-5366

 

Corn earworm and Fall armyworm trap catch numbers from Virginia sweet corn fields – Week of July 16

Sweet corn farms are being monitored around Virginia for the two most important pests attacking the ears, corn earworm and fall armyworm.  Moth Trap Catch Data are being recorded by:  Katlyn Catron & John Few (Montgomery Co.); Jason Cooper (Rockingham Co.); Ursula Deitch (Northampton Co.); Helene Doughty (Accomack Co. & Virginia Beach); Kenner Love (Rappahannock Co.); Laura Maxey Nay (Hanover Co.); Steve Pottorff (Carrol Co.); Stephanie Romelczyk  (Westmoreland Co.); Laura Siegle (Amelia Co.); Rebekah Slabach (Halifax Co.); and Mark Sutphin (Frederick Co.).

This week we have still not seen the fall armyworm flight yet in VA.  A few moths were caught on the Eastern Shore of VA and a couple other locations, but generally they are not in Virginia yet from their migratory flight from the south each summer.  For corn earworm, trap catch of less than 1 per night means relatively low pest pressure and sprays can probably be spaced 5-6 days apart during silking.  However, a catch of >1 or >13 moths per night means moderate and high pest pressure, respectively and a more frequent spray interval (every 3 or 2 days) is justified.  Trap catch increased to high levels on several farms this week throughout the state including Northampton Co., Virginia Beach, Page Co., and Montgomery Co.

Here are the trap catch results (moths per night) for several locations around Virginia for this week (note we do not have data for all locations):

Week of July 16 (avg)
Region County Field CEW/night FAW/night
Eastern Shore Accomack ESAREC – cemetery 4.4 3
Eastern Shore Accomack ESAREC – woods 1.1 0
Eastern Shore Northampton Bridge Tunnel 33.3 0
Eastern Shore Northampton Capeville 1 1.5 0
Eastern Shore Northampton Cape charles 3.0 NA
Eastern Shore Northampton Eastville 4.5 0
Eastern Shore Northampton Nassawaddox 1.5 0
Virginia Beach Virginia Beach Pungo 1 15.7 0
Piedmont Amelia Field 1 4.0 0.2
Piedmont Hanover Farm 1 3.7 0.0
Piedmont Hanover Haynes 1.1 0.0
Northern Neck Westmoreland Field 1 10.0 0
Northern Neck Westmoreland Field 2 3.7 1
Shenandoah Valley Rappahannock Field 1 5.0 0
Shenandoah Valley Page Field 1 12.0 0
Shenandoah Valley Frederick Farm 1 7.4 0
Shenandoah Valley Frederick Farm 2 3.2 0
Shenandoah Valley Rockingham Farm 1 0.3 0
Shenandoah Valley Rockingham Farm 2 1.0 0
New River Valley Montgomery KC 1.0 0
New River Valley Montgomery KO1 3.3 0
New River Valley Montgomery KO2 9.3 0
New River Valley Montgomery WF1 16.3 NA
New River Valley Montgomery WF2 4.3 NA
New River Valley Montgomery WF3 13.0 NA
New River Valley Montgomery WS1 17.3 NA
New River Valley Montgomery WS2 19.0 NA
New River Valley Montgomery WS3 36.7 NA

Corn earworm and fall armyworm trap catch numbers in Virginia – Week of July 10, 2017

 

Corn earworm larva in sweet corn.

Corn earworm and fall armyworm are two important pests of a number of agricultural crops in Virginia.  Sweet corn, in particular, is extremely vulnerable to attack by the larvae (or caterpillars) of these moth pests.  Monitoring moth catch numbers in pheromone-baited traps can help IPM decision-making.  See at the end of this post the Action threshold for spraying insecticides on sweet corn based on corn earworm trap catch.  In general trap catch less than 1 per night means relatively low pest pressure and sprays can probably be spaced 5-6 days apart during silking.  However, a catch of >1 or >13 moths per night means moderate and high pest pressure, respectively and a more frequent spray interval is justified.

In 2017, we are monitoring these pests on sweet corn farms in 11 different counties in Virginia.  Moth Trap Catch Data are being recorded by:  Katlyn Catron & John Few (Montgomery Co.); Jason Cooper (Rockingham Co.); Ursula Deitch (Northampton Co.); Helene Doughty (Virginia Beach); Kenner Love (Rappahannock Co.); Laura Maxey Nay (Hanover Co.); Steve Pottorff (Carrol Co.); Stephanie Romelczyk  (Westmoreland Co.); Laura Siegle (Amelia Co.); Rebekah Slabach (Halifax Co.); and Mark Sutphin (Frederick Co.)

Here are the trap catch results (moths per night) for several locations around Virginia for this week (note we do not have data for all locations):

Region County Field CEW  moths/night FAW moths/night
Eastern Shore Accomack ESAREC 1.1 0
Eastern Shore Virginia Beach Pungo 1 1.6 0
Eastern Shore Virginia Beach Pungo 2 3.9 0
Eastern Shore Northampton Bridge Tunnel 6.6 0
Eastern Shore Northampton Capeville 1 3.6 0
Eastern Shore Northampton Capeville 2 0.0 0
Eastern Shore Northampton Eastville 0.6 0
Eastern Shore Northampton Nassawaddox 1.0 0
Piedmont Amelia Field 1 2.7 0
Piedmont Hanover Field 1 2.1 0
Piedmont Hanover Field 2 1.0 0
Northern Neck Westmoreland Field 1 3.0 0
Shenandoah Valley Rappahannock Field 1 1.0 0
Shenandoah Valley Frederick Field 1 2.3 0
Shenandoah Valley Frederick Field 2 3.5 0
New River Valley Montgomery Whitethorne 1.9 0
New River Valley Montgomery Wall field corn 1.1 0
New River Valley Montgomery Wall sweet corn 20.8 0

 

Action threshold: Number of Corn Earworm Moths Caught in Pheromone trap
Per Day Per 5 Days Per Week Spray Interval for sweet corn
<0.2 <1 <1.4 No Spray
0.2 – 0.5 1.0 – 2.5 1.4 – 3.5 6 Day
0.5 – 1.0 2.5 – 5.0 3.5 – 7.0 5 Day
1.0 – 13.0 5.0 – 65.0 7.0 – 91.0 4 Day
>13.0 >65.0 >91.0 3 Day

 

 

Aerial applications effective for stink bugs

Last week the entomology department followed up on aerial spray applications for stink bugs. These applications were very effective (>98% mortality). If you are considering spraying for this pest in your corn, NCSU recommends bifenthrin as the pyrethroid of choice. This is consistent with spray trials at the Tidewater AREC that showed poor control with lambda-cyhalothrin (karate, warrior II). All pyrethroid insecticides must make contact with the insect to kill it and there will be poor, if any, residual control. We recommend waiting to treat until all wheat is harvested in the nearby area. So far, there have been no infestations at threshold in corn fields that are greater than 1/4 mile from wheat. Currently, we are scouting Virginia’s eastern shore where the wheat harvest is in progress.

 

Failed Corn Stand: Starting Over

Charlie Cahoon and Michael Flessner

Virginia Tech Weed Science

Over the past few days we have had several questions concerning replanting corn behind an already failed corn stand.  Our biggest concern in this situation is how to terminate emerged corn from the first planting.  The best option for small corn (4-8 inch) is clethodim (Select Max or generics).  The label for Select Max (0.97 lb active ingredient/gal) specifies 6 oz/A must be applied at least 6 day prior to replanting.  Clethodim products that contain 2 lb active ingredient/gal and are labeled for this situation should be applied at 3 oz/A, while adhering to the same plant-back restriction.  As is the case with many weeds, timeliness is critical.  Control of larger corn by clethodim is variable (> 8 inches).

Poor corn stand as a result of bird damage. Painter, VA 2017.

Producers not wanting to wait 6 days before replanting should use paraquat (at least 3 pt/A of a 2 lb/gal product or 2 pt/A of a 3 lb/gal product).  Paraquat should not be used alone; adding atrazine (1 pt/A) and suggested adjuvants to paraquat will enhance control.  Research conducted by Dr. Kevin Bradley (University of Missouri) and Larry Steckel (University of Tennessee) concluded Liberty did not consistently control Roundup Ready corn.  Although not listed on the bag, many corn hybrids are tolerant to glufosinate (active ingredient in Liberty).  For these reasons, producers should be wary of using Liberty to terminate a failed corn stand.

Another common question when replanting corn is whether to reapply residual herbicides such as atrazine. Atrazine and other residual herbicides should not be reapplied. If additional atrazine is desired in a postemergence application, just note that the cumulative total atrazine for your first and second planting of corn cannot exceed 2.5 lb active ingredient per acre per year.  Other products have similar restrictions.

On a normal year, growers are usually asking if soybean can be planted behind corn.  And our answer to this is usually no.  This is mostly due to the fact that most everyone uses atrazine preemergence and planting soybean following atrazine if very risky.  The label of most atrazine products says “Do not rotate to any crop except corn or sorghum until the following year, or injury may occur” and “If applied after June 10, do not rotate with crops other than corn or sorghum the next year, or crop injury may occur”.

 

Wheat Disease Update – May 2, 2017

Following last week’s rain, the risk for Fusarium head blight (FHB or scab) infections has increased, and the risk is very high even for moderately resistant varieties in certain portions of the state (see FHB Risk Map). Much of the wheat crop is beyond the early flowering stage, but for fields where wheat is currently flowering a fungicide may be needed to protect the crop from FHB infection and DON contamination. Recommended fungicides include Caramba, Prosaro, and Proline. Fungicides are most effective when applied at the start of flowering and up to a week later. The greatest coverage of the heads can be achieved by applying fungicides in 5 gal/A by air and 15 gal/A by ground with a 300-350 um droplet size and nozzles angled forward at least 30 degrees.

FHB risk on May 2, 2017 for moderately resistant wheat varieties. Susceptible wheat varieties that are currently flowering are at high risk for FHB infection throughout Virginia.