CEW moth activity is definitely beginning to increase. We are now catching 20-30 per night in our traps compared to 4 or 5 per night last week. We are not sure how this will progress. A lot will depend on the weather, and eventually, corn harvest. We will keep posting updates.
PEANUTS: We are beginning to find just a few worms in peanut fields—way below any reasonable threshold (See the advisory I posted on the peanut/worm situation for more details).
SORGHUM: A few worms are beginning to show up in sorghum heads (See the advisory I posted on sorghum head worms).
SOYBEAN: We are getting reports of a few worms in soybean fields but not at threshold levels, and not threatening the seed.
COTTON: Although we have found a few CEW eggs, we are finding almost no worms. This could be year when the BG2 and WideStrike provide enough protection, without additional foliar sprays.
PYRETHROID RESISTANCE: Keep in mind that I use the term ‘resistance’ loosely. We cannot prove/disprove actual resistance using the AVT (Adult Vial Testing) method, only determine the percent that survive the pyrethroid challenge. So, where do we stand this year? If you open the file (‘more’ button) you can get a quick comparison of where we are compared to last year—so far we are seeing only about 30% survivorship. But also notice that the number of moths tested to date is very low, which could bias our results. Is 30% survivorship enough to warrant a shift to a non-pyrethroid—my answer is, it depends. My rule of thumb is—if a field is at or just above the threshold (check that for each crop), a pyrethroid applied at the highest labeled rate, using a spray system that achieves good plant coverage, will do well. But, if a field is 3 to 4 times the threshold, or higher, a non-pyrethroid will be needed.
Additional information: cew-avt-results-aug-13-pptx