Category Archives: Insect

Corn earworm and brown marmorated stink bug update for July 14, 2016

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Black light trap captures of corn earworm moths have been very low this past week in Suffolk (2 total moths) and Warsaw (zero moths).  Captures in the Suffolk pheromone traps also dropped off this week.  However, field corn and sweet corn samples suggest that we may see higher numbers of corn earworm (aka bollworm) in other crops this season.

We have started catching brown marmorated stink bug (BMSB) in the black light traps in Suffolk (5 total in the past week) and in Warsaw (4 total this week).  I don’t recall ever catching that many in Suffolk before.  Our soybean scouts are beginning their statewide survey for BMSB (and kudzu bug) and we will keep you informed on these pest population levels throughout the season.

Sugarcane aphid update for July 14, 2016

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Our team has been scouting sorghum for sugarcane aphid in Isle of Wight, Southampton, Suffolk, and Sussex counties, but we have not detected them yet this season.  They have been found in North Carolina, and with their ability to spread and reproduce rapidly, we recommend starting to scout sorghum for this pest.

There are several aphid species that can be found in sorghum, but sugarcane aphids are cream yellow in color with two, short dark cornicles (“tailpipes”) on their hind end.  Start weekly scouting at the field edges, especially checking the underside of lower leaves.  Once insects are found, scouting should be conducted at shorter intervals to actively monitor population growth.  Dr. Dominic Reisig, Extension Entomologist at North Carolina State University, provides these thresholds for sugarcane aphid.

When pesticides are needed, we recommend Sivanto (which has a FIFRA Section 2(ee) Recommendation for a reduced rate of 4-7 oz/A, including Virginia), or Transform WG (which is registered under a Section 18 emergency exemption for Virginia at a rate of 0.75-1.5 oz/A). Good coverage is essential.  Please refer to (and follow!) the labels for more details, including the maximum amount that can be applied annually, pre-harvest intervals, etc.  Repeat applications, when needed, should rotate active ingredients.   Pyrethroids are not recommended.

Corn earworm update for July 7, 2016

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Our black light trap at the Tidewater AREC in Suffolk is just now beginning to catch low numbers of corn earworm moths–we had 4 total this past week.  The Eastern Virginia AREC in Warsaw is not catching them yet.

We have caught some corn earworm moths in our pheromone traps in Suffolk (pheromone traps often out-perform black light traps early in the season for this species).  We have conducted vial tests on 160 moths since late June, and have seen quite high levels of survival for the start of the season (an overall average of 38.6% of moths surviving the vial test).  As in the past, we are exposing these moths for 24 hours to vials treated with a standard pyrethroid insecticide, cypermethrin, at 5 micrograms per vial.  For comparison, in 2015 we had about 21% survival at this time of the season, with  a peak survival rate of 51% occurring in late August.  We will continue to provide updates on this issue.

Corn earworm moths in the cypermethrin vial test

Corn earworm moths in the cypermethrin vial test

Stink bugs already in small grain and field corn

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Our overall mild winter and wet spring are the kinds of conditions that favor survivorship and early development of stink bug populations. Because of these conditions, this could be a summer when we see higher than normal stink bug infestations in a lot of crops including field corn, cotton and soybean. Brown stink bugs are already being found in small grain fields and areas of North Carolina are reporting pretty heavy stink bug pressure on seedling field corn.  See this article by Dr. Dominic Reisig at the NCSU station on Plymouth for details https://entomology.ces.ncsu.edu/2016/05/how-to-avoid-a-stink-bug-disaster-in-corn-2/

We need to be thinking ‘stink bugs’ this summer and aligning our field scouting, sampling and threshold efforts in that direction as the summer progresses—and that applies to cotton and soybean fields as they mature.

True armyworm infestation reported in small grain on Eastern Shore

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It’s been many years since we’ve seen a true armyworm (see the attached image) infestation in our small grain crop, but one is reported to be ongoing in the barley and wheat fields on the Eastern Shore. These caterpillars can do two types of damage—leaf feeding and head cutting.  Leaf feeding is rarely extensive enough to warrant control, especially if fields are within a couple of weeks of harvest.  Head cutting is less tolerable.  For some reason no one has been able to explain, caterpillars will sometimes eat through the stem below the heads casing them to drop to the ground.  Finding otherwise healthy looking heads-short stems on the ground is a good indicator that true armyworms are present and still active.  It is often hard to find them on plants during the day as they typically feed more at night and seek cover under plant residue during the day.  When we have worked with this pest, we found that fields with the most plant residue on the soil surface tended to have the heaviest infestations.

We do have thresholds for true armyworm for those motivated to scout for them. As a general rule, barley should be treated if the number of armyworms exceeds one per linear foot between rows and most of the worms are greater than 0.75-inch long. In wheat, armyworms tend to nibble on the tips of kernels rather than clip heads; thus, populations of two to three worms per linear foot between rows are required to justify control. In high management wheat fields with 4-inch rows, treatment is recommended when armyworm levels exceed 3 to 5 per square foot of surface area, or per linear foot of row.

If a treatment is warranted, there are a few good choices but the PHI (Pre Harvest Interval) may be a challenge. Some work we did many years ago showed that pyrethroids were generally effective but have a PHI of 14 days (example, Mustang Max) to 30 days (example, Baythroid), which could be a problem for barley, wheat not so much. Lannate has a PHI of 7 days but did only an OK job in our trial and not as good as the pyrethroids. We chalked that up to the fact that although Lannate has great efficacy against most caterpillar species, it has almost zero residual activity. So a day-time spray may not have had as much horsepower by the evening when caterpillars become active. Since our work was done, several new products have been introduced to the market that we have not tested, like Prevathon (PHI 14 days), and Besiege (PHI 30 days). These should work well. See the Pest Management Guide Field Crops 2016, 4-49, p. 53 for more product listings (http://www.pubs.ext.vt.edu/456/456-016/Section04-Insects-1.pdf).

With any treatment, coverage will be essential so deliver the highest volume you can live with and direct it to go as deep into the canopy as possible.

TAW_larvae

Section 18 granted for use of Transform to control sugarcane aphid on sorghum

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EPA just granted a Section 18 for use of Transform™ WG in Virginia against sugarcane aphid in sorghum. Transform (50% a.i. sulfoxaflor), manufactured by Dow AgroSciences, may be applied through April 8, 2017 on a maximum of 16,591 acres of sorghum fields (grain and forage) in the following counties: Accomack, Albemarle, Alleghany, Amelia, Appomattox, Augusta, Bedford , Botetourt, Brunswick , Campbell, Caroline, Carroll, Charlotte, Charles City, Culpeper, Cumberland, Dinwiddie , Essex, Fauquier, Floyd, Fluvanna , Franklin, Frederick, Gloucester, Goochland, Greensville, Halifax, Hanover , Henrico, Isle of Wright, George , King William, King and queen , Loudon, Louisa, Luneburg, Madison , Mathews, Mecklenburg, New Kent, George , Prince William, Rockbridge , Rockingham , Russell, Southampton, Spotsylvania, Suffolk, Surry, Sussex, Virginia Beach, Washington, Westmoreland, and Wythe. 

The following directions, restrictions, and precautions must be observed. Foliar applications may be made by ground or air at a rate of 0.75-1.5 oz of product (0.023-0.047 lb a.i.) per acre. A maximum of 2 applications may be made per year, at least 14 days apart, resulting in a seasonal maximum application rate of 3.0 oz of product (0.09 lb a.i.) per acre per year. Do not apply product 3 days pre-bloom or until after seed set. 

To minimize spray drift and potential exposure of bees when foraging on plants adjacent to treated fields: applications are prohibited above wind speeds of 10 miles per hour (mph) and must be made with medium to course spray nozzles (i.e., with median droplet size of 341 µm or greater). A restricted entry interval (REI) of 24 hours applies to all applications. Do not apply within 14 days of grain or straw harvest or within 7 days of grazing, or forage, fodder, or hay harvest. 

Environmental Hazards Statement: “This product is highly toxic to bees exposed through contact during spraying and while spray droplets are still wet. This product may be toxic to bees exposed to treated foliage for up to 3 hours following application. Toxicity is reduced when spray droplets are dry. Risks to pollinators from contact with pesticide spray or residues can be minimized when applications are made before 7:00 am or after 7:00 pm local time or when the temperature is below 55 degrees Fahrenheit (°F) at the site of application.” 

We will provide updates on the presence and spread of sugarcane aphid as the season progresses.

 

Stakeholder input on Virginia’s State Pollinator Protection Plan

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The following advisory is posted on behalf of Dr. Hunter Frame:

I want everyone to check out this letter for stakeholder input on the pollinator protection plan that is being developed by VDACS. So for the cotton producers the nearest meeting will be on February 22 from 6-8 pm at the Tidewater Agricultural Research and Extension Center in Suffolk, VA. This is an important issue that needs to be discussed and solutions need to be developed so no tools for producers are lost and bees/beekeepers are able to thrive next to cotton and other crops! Look forward to seeing everyone there!

http://www.vdacs.virginia.gov/pdf/pollinatorprotectionplanletter.pdf

26th Annual Eastern Shore of Virginia Ag Conference & Trade Show

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The Eastern Shore of Virginia Ag Conference & Trade Show is on! We are snow free, and looking forward to a great event on January 26 and 27, 2016. The event will take place at the Eastern Shore Community College Workforce Development Center in Melfa, VA. The full program can be found at: http://issuu.com/esarec/docs/flipbookfinal/1. We have been approved for Certified Crop Adviser (CCA) CEU credits (details at: https://www.dropbox.com/s/f34f3spg4quni7a/CCA_Credits_Handout_2016.pdf?dl=0), Virginia Nutrient Management Credit (1 credit), and Virginia Pesticide Recertification credits (information in the program). See you there! Directions can be found at: http://es.vccs.edu/about/mapdirections/.ESCC

Eastern Shore Ag Conference & Trade Show

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Join Virginia Tech, Virginia Cooperative Extension, the Virginia Association of Potato and Vegetable Growers, and Industry to hear updates, research information, and innovative products for grain, oilseed, and vegetable crops important to Virginia’s Eastern Shore on January 26 and 27, 2016. This event is free and open to the public. Announcements concerning conference updates, weather delays and/or closings, etc. will be made at: https://www.facebook.com/EasternShore.Soils. Highlights of the program can be found in the attached flyer.

Ag Conf Press Release 2016

Helicoverpa zea (corn earworm/bollworm) adult vial test update for Sep. 24, 2015

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We’re not catching many moths in our pheromone traps this time of year, but we are still conducting the adult vial tests on those that we do catch.  We are currently seeing many more dead moths after 24 hours of exposure to the pyrethroid insecticide, cypermethrin, at the 5 microgram per vial rate.  Less than 20% as you can see in the line graph below.  For the season, the average survival rate is 33.4% (bar chart, below).

CEW_AVT_24_Sep_2015_aCEW_AVT_24_Sep_2015_b