Alabama Peanuts: Decline in Moth Activity, Watch for Three-Cornered Alfalfa Hoppers

Threecornered alfalfa hopper. Photo: University of Tennessee

This report is based on sticky wing pheromone trap catches from 16 locations and direct crop scouting, along with information from producer calls.

The overall population trends (see charts at bottom of this post) indicated a sudden drop in moth activity with the high precipitation levels seen in June.

  • For example, a 10 to 11 inch rainfall in central Alabama caused sudden drop in beet armyworm, corn earworm, tobacco budworm, and lesser cornstalk borer moth activity.
  • Looper and fall armyworm activity was at low levels in peanuts in June.
  • However, recent drier weather in July with high heat has reversed some of these trends with sudden increase in moth activity and caterpillar action on peanuts.
  • Therefore, producers should scout the crops and record the pest spectrum that is out there now.
  • The recently updated Alabama Peanut IPM Guide contains detailed insect pest scouting recommendations.

Another group of insects becoming activate with drier July is the sucking insect pests. The three-cornered alfalfa hopper (TCAH) number is expected to increase rapidly in peanuts with continued humid weather and rising heat.

You may encounter some of the nymphs of the hopper that have a row of spines on their back and sit still on peanut stems sucking on plant sap. Keep a close watch on TCAH and don’t let them migrate into the canopy near the pegging branches.

Use a stick to strike the peanut plants and count the nymphs that get dislodged.

We have a number of insecticides registered for caterpillar control in peanuts. These insecticides belong to chemical classes 3A, 5, 11, 15, 18, 22, and 28. Producers should actively rotate insecticide chemistries to avoid pest resistance and loss of natural enemies.

Synthetic pyrethroids are great for knock-down effect but they can also induce spider mites in hot dry weather. If producers anticipate dry weather in their area (especially during pod-filling stage), then switching to insect growth regulator or one of the newer generation insecticides can very effectively control small caterpillars with a long residual.

Some premix products like Beseige can provide a broad range of insect control later in the season.

The 2016 spider mite trials in Alabama indicated nearly 29% yield loss with pesticide-induced spider mite infestation – we don’t want to see that kind of production loss on commercial fields.

When in doubt, please call a regional extension agent or this author (251-331-8416) for insect identification and developing an IPM plan for your crop.

Click on charts to enlarge view


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