For the most part the answer is not yet! It’s important to protect your cotton crop from insect feeding until NAWF5 + 350 DD60’s. This general rule applies to a complex of our common pests, but in reality, you can probably quit worrying about plant bugs at about 300 DD60s, whereas for stink bugs and bollworms, the number is closer to 400 DD60s because they will feed on larger bolls.
- However, it is very unlikely that fields that do not have significant insect infestation at NAWF5 + 350 DD60s will develop economically damaging problems after that point. The cotton is becoming less attractive, and the bolls are rapidly getting more resistance to insect feeding.
- Obviously, it is important to document when a field reaches cutout, NAWF5 (= cutout). Cutout is when the average plant has 5 nodes above a first position white flower. I like to start the clock once the field first drops below NAWF5. Assuming the crop is managed for insect pests, insecticide treatments can then be terminated once 350 DD60s are accumulated.
- If you forgot how to calculate DD60s that are accumulated each day, it a simple formula. Average the high and low temperature for the day and subtract 60. Thus, if the high is 90, the low was 70, the average temperature was 80F, and you accumulated 20 DD60s for that day (= 80 – 60). Typically, it takes 15-20 days to accumulate 350 DD60s.
If you call and tell me that “I’m 2 nodes above white flower”, I can only guess that you are probably close to NAWF5 + 350DD60s based on past experience, but you really should document the date of cutout (NAWF5).