This square blasting causes plants to remain in a vegetative state, delaying fruiting and fiber maturity. Carbohydrate stress can also cause squares to be shed under cloudy conditions. Be sure that insects are causing trouble before you use insecticides. If you spray for plant bugs, check sprayed fields weekly for aphids and bollworms throughout the remainder of that season. Damaged leaves curl down at the edges.
Aphids are more common after insecticide applications have been made.
Insecticidal control of aphids is rarely needed in Missouri because beneficial insects normally control them. Aphid buildup may result in some leaf curling and honeydew deposition. Control may be required under these conditions. Spider mites Spider mites are tiny greenish, tan or red mites that may be found on the underside of leaves. They may attack cotton at any stage of growth, but they generally cause more damage in mid to late season following hot, dry weather.