Cotton fruits over a long period of time compared to most other crops and attracts many species of insects, many beneficial, but a few damaging ones. When cotton reaches the fourth or fifth week of bloom, the few bad insects such as escape bollworms, plant bugs, or especially stink bugs, in the southern cotton growing areas of the US, often overwhelm the good insects. At this time many fruit, especially bolls, are at risk. Unfortunately, a decision has to be made to control the harmful bugs. Most of the bad bugs, such as stink bugs, cannot be controlled with selective insecticides. As a general rule, if a grower can get to this point in the season without using hard insecticides, beneficial insects have carried it as far as they can and a decision has to be made to protect the fruit rather than conserve beneficials. This is a difficult decision since there may be millions of lady beetles, pirate bugs and other species present per acre. However, when we get to the gin in the fall, they will only weigh the cotton and not the beneficial insects. Beneficials are a great resource but they are just NOT any help against plant bugs and stink bugs.
We have very good thresholds for these damaging bugs, based on many years of research conducted throughout the cotton belt. When the damage threshold is exceeded, controls must be applied in order to protect the fruit and make cotton production economical. When cotton is planted during our desired planting window of late April to mid May, cotton reaches this fourth or fifth week of bloom about the last 10 days of July. This is the time we have to make the decision to either conserve beneficials or protect the fruit. In order to maximize yields and profits we should choose to protect the fruit. Beneficials are a cost free resource in cotton but they can only take us so far.