Insect Calls of the Week (August 1, 2019)

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I don’t think I have had a call about soybean all week, but my observations suggest we need to be scouting for stink bugs in our earliest beans, and in some areas, kudzu bugs. Thus far, caterpillar infestations have been very light. As the bollworm flight increases, closely scout for corn earworm in late-maturing soybean fields, particularly in the Mississippi River Bottom areas where we historically have some problems.

Bollworm in Cotton – I am starting to get a few calls about bollworm larvae in fields of WideStrike (not WideStrike 3) and Bollgard 2 fields, some at treatment level. It’s time to knuckle down on scouting for bollworm infestations. Please refer to my previous article about treatment thresholds for bollworm and insecticide options at http://news.utcrops.com/2019/07/thinking-about-bollworm-management-in-cotton/.

Plant Bugs in Cotton: Without question, plant bugs are the number one call in cotton, but stink bugs are also in the mix. This is not surprising. Most folks are reporting good control with their insecticide applications. A few have been surprised how quickly plant bugs bounced back after treatment, even with ‘go to’ products, giving the illusion of a poor control. In reality, this is often the result of treating a rapidly increasing population. Below are some old data making this point. In this test, plant bug numbers on the day of treatment were slightly above threshold (= 3.2 bugs per drop cloth). At 5 days after treatment populations were still slightly above threshold, and 6 days after a second application, infestations levels had increased to twice the recommended threshold. This may look like a failure, but when you look at plots that were not treated with insecticide, you will see that two applications provided 80% control. Not perfect, but certainly not a failure. My point is, it almost always requires consecutive application on a 5-7 days interval to control exploding plant bug numbers. Refer to my previous article about ‘go to’ insecticide options for plant bugs and stink bugs at http://news.utcrops.com/2019/07/crunch-time-for-cotton-insects/.

Effect of two insecticide application on plant bug infestations

 

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