Tuesday, June 13, 2017

Heat Damage to Cotton Mimics Thrips Damage

Kerry Siders, IPM Agent in Hockley, Cochran and Lamb counties, has posted a special edition newsletter that describes heat damage to cotton that may be mistaken for thrips damage. The reprint is below.

Special Edition West Plains IPM Update - Not Thrips Damage

So I have received a few calls about seeing what was thought to be thrips damage to cotton, even on 4-7 true leaf cotton. See damage referenced in pictures below. So the scouts and I are finding a few thrips but in most all cases well below threshold. The damage you are seeing below and I suspect in many if not most all fields is this cupped, puckered, damaged cotton leaves. Looks like thrips, but if you look on the underside you do not see the feeding damage from thrips rasping on the leaf causing rupture of tssue and leaking of plant fluids. This then results in a scared silver tissue. The damage we are seeing now is on the uppermost new tender leaves. This is caused by the hot desiccating winds. So it may be 102 degrees out there, but that bare soil surface could reach well over 120 degrees. Combine that with the constant wind, that will pucker anything up. So what happens is the tender leaf margins become desiccated or injured to a point where they cannot develop normally. Meanwhile the leaf continues to develop around the center portion of the leaf causing this cupped appearance. This is not thrips, not herbicide damage, no disease, no genetic failure, just plain HOT! And until this weather breaks with a more moderate temp of less than 97 degrees, decreased wind speed, higher humidity, needed rainfall - these symptoms will continue to be seen in cotton as well as other crops. I am seeing the same thing in peanuts today.