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This is Jack Bacheler, Extension Entomologist at NCSU with the Thursday Cotton Insect Update. Today is Thursday, June 19.

Although we’ve had some welcome relief from the recent hot 95-100 degree weather of the past week, our continued dry weather over most of the state isn’t doing us any favors. Cotton can still tolerate dry weather reasonably well for the next week or so. Corn is another story, and is suffering as tasseling gets underway. Cotton growth over much of the state has advanced well, and initiation of blooming is getting close from some. Blooming will be a period of accelerated water demand, so we hope that rainfall events become more generous with July fast approaching.

Even in conventional cotton, bollworms and tobacco budworms should leave cotton alone until the major moth flights into cotton in mid to late July. Bollworms prefer corn at this time of year, and this pre-bloom generation of budworms typically does not reach treatable levels. In any Bt technology cotton (Bollgard, BG II, or Widestrike), pre-bloom damage from bollworms is unusual. With tobacco budworms, damage to Bt cotton lines at any time during the growing season has not yet been found in the US. Be aware that the 5% unsprayed refuge (or the 5% embedded non-Bt cotton that can be spraying along with the Bollgard line) and the 20% sprayed refuge requirement is still in place for Bollgard cotton, but no refuge is needed for BG II or Widestrike cotton. Widestrike and BG II lines are also resistant to damage from cabbage and soybean loopers and beet and fall armyworms.

Although we have had only a few reports of light infestations of spider mites and cotton aphids, both of these pests can build up quickly, and the weather appears to be ripe for mite outbreaks. Scouts and producers should be on the lookout for speckled or bronzy leaves indicating spider mites, or drooping terminals that sometimes indicate cotton aphids. Both of these pests are relatively easy to scout for – but only if you’re looking.    We’ll provide updates on managing these two pests as problems arise. You can also brush up on these and other pests by looking over our illustrated Cotton Scouting Guide at: <http://ipm.ncsu.edu/cotton/insectcorner/scouting_guide.htm>

At this time, we would also recommend the routine taking of square retention counts as an indication of plant bug activity. The percentage of retained square provides us with a quick and easy way to determine if further sweep net or ground cloth samples are needed. If square retention is above 80%, no further sampling is needed. Details on taking square retention counts and additional sampling for plants bugs and their damage can also be found at the above web site.

We’ll see you next week on June 26. See you then.