The weather has made making timely treatments for thrips control in cotton a challenge, and thrips numbers are peaking this week. Earlier cotton is between 5-7 true leaves and is pretty much out of the woods for thrips. However, some 4th leaf cotton that has not already received a foliar application may benefit from treatment. In most circumstances, I would suggest making a foliar application for thrips on any later planted cotton ASAP. This cotton has been exposed to high thrips pressure and cool and wet feet. I discussed insecticide options in a previous article.
Some cotton is now squaring, and I’m already getting reports of treatment level numbers of tarnished plant bugs in some fields. Plant bugs will often concentrate on the first fields that begin to square. Reminder – the threshold for plant bugs in cotton during the first two weeks of squaring is 8 or more bugs per 100 sweeps. Our goal is to maintain 80% square retention or higher. Recommended insecticide during the pre-bloom window are listed below. There are many different trade names and formulations of imidacloprid products available. Be sure what you have, and I suggest using the higher rates listed below given the relatively low costs of imidacloprid products. For Centric, I’ve had good success using 1.5 – 1.75 oz during the first couple of weeks of squaring, but I recommend bumping up the rate as plants get bigger or when populations are way above threshold.
Yes, there are other options such as Acephate and Transform. However, I strongly suggest avoiding acephate prior to flowering. It may create problems with secondary pests such as spider mites or aphids, and this also helps with resistance management. Transform fits well during the pre-flower, but unless aphids are present in high numbers, I prefer to reserve its use until the cotton has begun to bloom. This is partly for resistance management and partly for budget management. The reality is that the timing of early-season applications is more important than the insecticide used. Nothing should be expected to provide more than 4-5 days control of adults that are migrating into a field. It’s too early to think about using Diamond which has limited effects on adult plant bugs. Diamond fits better just prior to or shortly after blooming has bugun.
Reminder – Bidrin or Bidrin XPII cannot be used in cotton between first square and first bloom.
Recommended Insecticides for Plant Bugs Prior to Bloom (amount per acre)
|Insecticide (Trade Names)||Lb AI/Acre||Amount Product|
|acetamiprid (Intruder 70WSP)||0.048||1.1 oz|
|clothianidin (Belay 2.13)||0.05 – 0.067||3 – 4 oz|
|flonicamid (Carbine 50WG)||0.081 – 0.089||2.6 – 2.8 oz|
|imidacloprid 2.0||0.047 – 0.062||3 – 4 oz|
|imidacloprid 4.0 (Couraze Max)||0.047 – 0.062||1.5 – 2 oz|
|imidacloprid 4.6 (Admire Pro)||0.047 – 0.062||1.3 – 1.7 oz|
|thiamethoxam (Centric 40WG)||0.0375 – 0.062||1.5 – 2.5 oz|