AQCA Commentary

July 27, 2010

By: Jeff Thompson, Manager

            As we approach the first of August, I am very pleased with the overall condition of the crop.  West Texas is staring at record yields that could quite possibly rival the 2007 crop.  In the Southeast and Mid-South, conditions are little more mixed due to random rainfall patterns.   Even so, cotton in these regions still holds tremendous promise.  Temperatures this summer have been oppressive with the heat rapidly maturing this crop.  Some of our earlier varieties such as, PHY 375, DP 0912, and others are quickly approaching cut out.  As water demand reaches its peak over the next few weeks, the fate of this crop will be dependent on timely August rains.

            Nowadays, with so much of our production costs front end loaded, producers are often hesitant to spend money late in the season.  Regrettably, as fate would now have it, our biggest threat from insects occurs at this time.  Since untreated fields can sustain severe economic damage over the next few weeks, I strongly encourage everyone to be very vigilant in controlling late season pests. This crop has too much potential not to take every measure possible to keep it protected.

 Stinkbugs - This insect has been elevated to a major cotton pest now that worm and weevil applications are few if any. I have never been a proponent of automatic insecticide applications, except when it comes to stinkbug control.  I would make it a point every year somewhere between the 3^rd and 5^th week of bloom (usually late July), to treat for this pest.  At present most of our cotton is beyond this stage, so I trust most have already begun treatments.  If you haven't, I would do so without hesitation.

            Stinkbugs will migrate into cotton from other crops such as corn or milo and weed hosts as they dry down and become less attractive.  Pay special attention to cotton fields located nearby.  The nocturnal feeding habits and skittish nature of stinkbugs makes them very difficult to detect in the field.  Monitoring for signs of damage provides a more accurate way to account for their presence. Pull 20 to 50 quarter sized bolls soft enough to be mashed between your fingers.  After crushing, inspect the inner wall of the boll for damage.  A point to remember is feeding punctures on the outside of the boll do not necessarily correlate to internal damage.  Recent research has shown treatment thresholds should change proportionate to the distribution of susceptible bolls.  In the 3^rd to 5^th weeks of bloom, treat if   10% or more of the young bolls exhibit internal feeding damage. In week 6 and beyond this threshold can be increased to 20 or 30 percent.

            The Southern green stinkbug and the brown stinkbug are the two most common species found in cotton.  Determining the predominant species within the field is critical to selecting the proper insecticide. Green stinkbugs are more susceptible to pyrethroids while brown stinkbugs will require an organophosphate, such as Bidrin for best control.  Recent field observations indicate a good mix of both species is present. When choosing an insecticide remember pyrethroids will give you added value by controlling any escaped bollworms.  

Bollworms - As expected, over the past few days we have seen an increase in moth activity. This is the traditional July bollworm moth flight coming off grain. Single gene Bollgard varieties (DP 555) and conventional varieties are more apt to experience escaped bollworms than Bollgard II or Widestrike varieties.  Scouting for worms becomes much more difficult and tedious at this time of year.  Eggs and worms more often will be found in or on white blooms which will require whole plant inspections rather than just checking the terminals of the plant.   Fortunately, if treatments are warranted cost effective pyrethroids should give adequate control.  Though escaped worms are less likely in Widestrike and Bollgard II varieties careful scouting is still advisable.

Until next time,