Cotton:  There are now a few mentions of bollworms being found in some cotton fields, although there have been no reports of high infestation levels.  The suggested treatment threshold is 4 “surviving” larvae per 100 plants on Bt cotton fields.  Typically, we do not count very small larvae because we want to give the Bt technologies a chance to work.  Consider increasing this threshold up to 8 larvae as you approach NAWF5 + 350 DD60s.  Much of our crop is late and is just now or has not reached cutout.  This means that you will need to maintain adequate worm control until September.  Pyrethroid insecticides at relatively high rates are still providing adequate control of bollworm infestations.  There are options to go with more expensive insecticides such as Prevathon or Besiege. These products provide more consistent and longer control, but at this stage of the game and given the light pressure so far, I would probably not go this route.

• It is very important to scout for bollworm in the middle of the canopy.  Do not overlook larvae that may be found under dried bloom tags or in pink or white blooms.
• WideStrike varieties typically do not provide the same level of protection as Bollgard II varieties.

Soybean:  It remains relatively quiet but insect action will pick up over the next several weeks.  A few things to keep in mind are presented below.

• Stink Bugs – Treat anytime up R7 when numbers reach or exceed an average of 9 per 25 sweeps.  However, you should consider doubling this threshold one fields pass R6 and approach R7.  In reality, treatment level infestations typically don’t occur until fields reach the R5 growth stage or later.  Pyrethroid insecticides are usually the materials of choice.  Bifenthrin is specifically recommended when brown stink bugs are common, but in most fields, 90% of the stink bugs encountered at this point of the season are green stink bugs.
• Corn Earworm (Bollworm) – There have been no reports of treatment level infestations, but an insecticide application is warranted if 9 or more larvae are found per 25 sweeps.  The higher the infestation level, the more important it is to use products such as Belt SC, Prevathon or Besiege that provide better and longer control.  Frankly, I would only consider a pyrethroid insecticide in cases where infestation are just above threshold and there are indications that it won’t be get much worse.
• Loopers and Green Cloverworms – These are the primary defoliating caterpillars found in Tennessee.  As of today, green cloverworms are being reported pretty commonly and few loopers are being found.  Treatment is suggested anytime defoliation exceeds 20% between R1 and R6.  You can relax this threshold to 30% between R6 and R7, and applications are not recommended once soybean fields reach R7.  Insecticide applications can also be triggered if high numbers of larvae are found while sampling.  For example, consider treating if 19+ loopers or 38+ green cloverworms are found per 25 sweeps.  Be sure you are identifying these species correctly.  Green cloverworm is easy to control (typically with synthetic pyrethroids).  Soybean loopers require the use of more expensive products such as Intrepid, Belt, Prevathon, etc.   Please refer to a previous article if you are unsure how to tell these pests apart.

Please refer to UT’s Insect Control recommendations for Field Crops for a complete list of recommended insecticides at rates.