Having passed through ‘thrips season’, we are having a little relief from insect pests. So far, there have been almost no reports of mid-season pests like aphids or mites. One field developed aphids in pretty high numbers but by the time it was discovered, tiny parasitic wasps had killed many of them. If we see more than 25% aphid mummies (the dried remains of parasitized aphids), and no insecticide is applied that would kill the wasps, the wasps will usually completely eliminate the aphid population within a week to 10 days.

Will plant bug populations be higher this year due to the somewhat wetter conditions? This is being talked about south of us where they are having a wetter than normal season. It is thought that wetter years result in more weeds and alternate hosts plants where plant bug populations can increase. However, most of our cotton area did not receive excessive amounts of rainfall, and some areas are actually getting pretty dry. We are seeing tarnished plant bugs in weeds and crop fields, but not in unusually high numbers. We are just beginning to assess fields for square retention, which is still the best way to determine the need for any action against plant bugs. Plant bugs feed on developing squares causing them to blacken and drop off, leaving a telltale scar where the square had been. With some training, it is fairly easy to inspect a cotton plant and find either blackened squares or the scars where squares were. We consider a field in the ‘safe zone’ if square retention is 80% or above. This is because cotton can compensate from loss of as much as 20% of the total square load without any reduction in yield. We proved this for ourselves some years back by doing a 2-year study where we removed up to 20% of the first position squares, on several varieties. No yield loss occurred.

As of this week, based on checking several fields and reports from field scouts in the private sector, our cotton fields are at greater than 90% square retention, which is what we generally see. A few fields to the south of us in North Carolina have been reported to be in the low 80% range, and one is at 75%. Plant bugs are spotty for sure, but all indications are that this year, like most, will be a low plant bug year.