Early-season insect activity on the Eastern Shore

We’ve had a somewhat slow start to spring on the Eastern Shore of VA with regards to insect pests. *****THRIPS******Over the past month we have collected flowering weeds (mostly mustard and henbit) around farms in Accomack and Northampton Counties to sample for overwintering thrips populations. Although we have found a few tobacco thrips, Eastern flower thrips, and Western flower thrips on the weeds, most flowers have been void of thrips, and overall the counts are less than they were this time last year. This is hopefully good news to farmers…, but we’ll see how populations build up in the small grains crops. ******Colorado potato beetle****** This week I found the first Colorado potato beetles coming to potato plants and mating. Egg-laying will soon follow, and probably has already begun in the Cape Charles potato-growing region. The vast majority of growers used an at-planting application of a neonicotinoid insecticide such as Admire, Platinum, or Venom, which should provide control of beetles until around June. *****Wheat***** Many growers on the Eastern Shore applied a pyrethroid insecticide this spring for aphids…I guess. This spray was probably not warranted. I’ve discussed this matter with Dr. Ames Herbert (Virginia Tech TWAREC), who has many years of experience with aphid pest management in wheat. Aphids seldom ever need to be sprayed on wheat in the early spring. Populations are rarely ever high enough, and natural enemies, particularly parasitoids, will soon catch up to the aphid populations and bring the densities under control. One grower from Northampton County called me this week to tell me that despite strong suggestions from the pesticide applicators to include a pyrethroid insecticide in the spray tank for wheat, he declined. A week later, he said that most of the aphids looked grayish and sick – aphid mummies from the parasitoids. He was glad that he didn’t spray. It’s seems like an easy decision. Sure, you are making a pass over the field anyway, and logic tells you that a pyrethroid is relatively cheap, and you should probably do it. Well even it is only $3 per acre, that’s $3 that probably most of our growers did not need to spend. One concern with aphids is vectoring Barley Yellow Dwarf Virus, but this would have been done in the Fall of the year, and spraying now would not matter. Cereal leaf beetle adults were present, but in very low numbers. Also, I recently heard a scout on the Eastern Shore tell me that in his many years of scouting wheat, he’s only seen two fields that exceeded threshold for cereal leaf beetle.

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