Author Archives: Thomas Kuhar

About Thomas Kuhar

Professor and VCE-Vegetable Entomology Specialist Department of Entomology Virginia Tech Blacksburg, VA

Eastern Shore Insect Trap Counts for Week Ending July 23

Mr. Kyle Sturgis and Bill Shockley have embarked on a more extensive insect pest trapping effort on the Eastern Shore. Click more to view a spreadsheet of pheromone trap catch and blacklight trap catch from various locations on the Eastern Shore of Virginia. This same spreadsheet will include other locations and will add new catch numbers on a weekly basis. We are getting organized to deliver a more comprehensive picture of the activity of major agricultural pest insects on the Eastern Shore.

In summary the spreadsheet shows the first real rise in counts of both corn earworm and European corn borer in the Mappsville and Assawoman areas of the Eastern Shore. Activity in Eastville appears to be low. There have been no catches of either beet armyworm or fall armyworm so far. It is early for those pests, although a fall armyworm infestation in late planted corn was seen in Northampton County this week.
Additional information: es-insect-trap-counts-7-16-10-7-23-10-xls

Insect trap counts on the Eastern Shore for Week Ending July 16

Blacklight trap catch in Painter this week again yielded very little activty from the major moth pest species. Weekly counts were as follows: 0 European corn borer, 0 armyworm moths, 2 corn earworm, 6 hornworm moths (increasing), 42 green stink bugs (increasing), 3 brown stink bugs (decreasing). We are still not seeing the main flight of corn earworm. Spider mites remain an important pest concern particularly in areas that have missed the rain, or commercial tomatoes. An outbreak of fall armyworm in late-planted corn was also reported this week. Coragen insecticide is a new option for fall armyworm control in early whorl stage corn. It has shown very good efficacy, with a long residual, and it is a safe chemical to apply.

New supplemental label for Belay applied aerially on soybeans, cotton, and potatoes

Attached is a Belay Supplemental label that has been approved by the EPA and is pending state approval. This Supplemental Label allows Belay to be applied aerially in soybeans, cotton, and potatoes. In addition, the aerial use rate is 3 to 6 fl oz/A. This is a higher use rate than the current ground application label (3 to 4 fl oz/A); however, the EPA has approved the change of the use rate for Belay when applied by ground in soybeans and cotton. That Supplemental Label will be out this coming week. Additional information: belaysuppl-label-aerialappl-2010-bel-0015-xcaflny-pdf

Insect pest activity on the Eastern Shore for Week Ending July 2

The blacklight trap counts in Painter were very low this week with virtually no key moth pests caught, except for 1 European corn borer, and 20 brown stink bugs, which was a big drop for stink bug catch from the previous week.

One arthropod pest that has cause some issues lately is spider mites. This pest will often have outbreaks when the weather is hot and dry. Commercial tomato growers are managing this pest with Oberon, Acramite, and Agrimek primarily. Another very good new miticide labeled on vegetables is Portal available from Nichino America.
Relative to vegetables soybeans have very few highly effective miticides. Growers can suppress high populations with Dimethoate, Lorsban, or Warrior. However, repeated sprays of these products can also flare up spider mites because they destroy predatory mites. The following text was taken from the Virginia Tech Pest Management Guide for Field Crops:

Mite outbreaks usually are associated with hot, dry weather, which accelerates reproduction and development. During periods
of high humidity and field moisture, a fungal disease can reduce populations but high temperatures can nullify these effects.
Outbreaks also are associated with the application of certain insecticides that kill natural enemies and/or seem to make the soybean
plant more nutritionally suitable for mites.
Check weekly for mites, starting in early July through August, especially during a hot, dry season. Concentrate on the field
borders and look for the early signs of white stippling at the bases of the leaves. Do not confuse mite damage with dry weather
injury, mineral deficiencies, and herbicide injury. If feeding injury is evident, press the undersides of a few damaged leaves on
white paper to reveal any crushed mites. Determine the extent of the infestation and assess the level of injury by examining 20
to 30 plants in the infested area. Field infestations often show defoliated or injured plants at some localized point, with injury
becoming less evident and extending in a widening arc into the field.
If isolated spots of mite activity are confined to the perimeter of the field, spot-treatment using ground equipment is recommended
to prevent further spread of mites into the field. If the infestation is distributed throughout the interior of the field, treatment
of the entire field is suggested if live mites are numerous (20 to 30 per leaflet) and more than 50 percent of the plants show
stippling, yellowing, or defoliation over more than one-third of the leaves. If rains come, mite development and survival will
decrease but may not drop to economic levels if heavy populations are developing under high temperatures.

Insect pest activity on the Eastern Shore for week ending June 25

Insect counts this week from the Blacklight trap in Painter, VA were as follows:
No corn earworms or armyworms; 4 European corn borer moths; 3 tobacco hornworm moths; 81 brown stink bugs; 8 green stink bugs. Thus, pest moth activity is low right now for all species; but brown stink bugs are quite active at present; probably flying out of wheat fields. These insects can cause serious damage to tomatoes, cotton, beans, sweet corn, and other crops. They move from crop to crop as fruit or pods form. Pyrethroid insecticides are often the cheapest and most effective control for these pests.

Thrips have been very active on crops with tobacco thrips feeding on the leaves of tomatoes and newly emerged beans; and flower thrips infesting the flowers of various crops. Some commercial tomato fields have experienced up to 5 thrips per bloom, which is very high. Some identifications of thrips samples brought to my lab have revealed that up to 50% of the flower thrips may be Western Flower thrips, Frankliniella occidentalis, which has been shown to flare up after repeated sprays from pyrethroid insecticides. Some other options for thrips control include Orthene on some crops like green beans, Radiant on most vegetables, Lannate, and most of the neonicotinoid insecticides (Provado, Actara, Venom, Assail, Belay, and Scorpion).

New Belay Insecticide label on vegetables

Valent USA announces the new Belay insecticide label on vegetables and other crops. Belay includes the neonicotinoid insecticide clothianidin, which has been used widely in the seed treatment Poncho. Our insecticide research trial results in Virginia have shown Belay to be as effective as other neonicotinoid insecticides for sucking pests and beetles on vegetables. Click More News to download a copy of the new label. Additional information: belaylabel-2010various-crops-pdf

New insecticide option for slug control on corn and soybeans – Lannate LV

In wet years, SLugs can be a serious pest problem on corn and soybeans. It has been many years since there has been any new pesticide registered for their control. Dupont recently announced the new registration of Lannate LV FOR USE ON FIELD CORN AND SOYBEANS FOR THE CONTROL OF SLUGS IN certain states in the U.S. The special label is attached. Click More News. Additional information: lannate-lv-corn-soy-dr1113-pdf

Stink bug pest pressure on corn on the Eastern Shore

Some no-till cornfields on the Eastern Shore are experiencing pest pressure from stink bugs. These insects can impact yield up to 10%. For corn seedlings and early whorl stage before silking, small developing ears (½ – ¾ inches long) can be damaged by stink bug feeding resulting in malformed ear development. Treat corn if 10 percent or more of plants are infested with stink bugs at or shortly
before ear shoots appear (about V15). Do not
treat stink bug infestations once silking has begun.
Most pyrethroid insecticides (such as Karate, Warrior II, Baythroid XL, Hero, Brigade, Prolex, Tombstone, and the generic equivalents, etc..) are effective against stink bugs.

Soybean looper problems in Northampton County

A lot of soybean fields in Northampton County, particularly in the Cape Charles area, suffered some late-season defoliation from soybean looper. There was a lot of concern about insecticide resistance in this often difficult-to-control pest, particularly after loopers appeared in fields after being sprayed with a pyrethroid. After hearing reports from some growers and cooperators and their experiences, pyrethroids such as Baythroid and Warrior, were effective against this pest if you got good coverage and penetration into the canopy. Also, follow-up sprays of Warrior appeared to clean up the larvae in some of the problem fields. It is more than likely that some of the soybean looper infestations that we had on the soybeans in Northampton County following sprays of Warrior or another pyrethroid were a result of poor coverage or possibly bad timing. It would have been very difficult for a low volume aerial application to penetrate all of the foliage that we had on our dense soybean canopies this year in Northampton County. It is possible that soybean loopers fed on untreated leaves in the lower canopy, then moved on to the pesticide covered upper foliage after the residual was gone.