We started checking for stink bugs this week. Many cotton fields are in the 3 – 5 week bloom period, which is an important time for stink bug management. So far, our numbers are below threshold. Scouting is important, because some scouts reports stink bugs present in one field and not an adjacent field.
Outside damage to boll and warts on inside
Lint stain
When walking through a field, pick 25 – 30 quarter size bolls. (A stink bug can damage any size boll, they just prefer smaller bolls.) Inspect the inside and outside. Many times, we see damage on the outside that is NOT from SB. Scouts tell me it is better to count damage when 1) warts are seen or 2) lint is stained. However, large spots like the ones seen above is likely from SB.
When we scout for stink bugs, the boll injury threshold is adjusted up or down based on the number of susceptible bolls which are present. Below is the threshold from UGA Extension Phillip Roberts:
Higher stink bug populations are typically observed on later planted cotton. For brown stink bug, organophosphates should be used. Also, if other pests are observed, such as spider mites or white flies, we need to be careful in insecticide selection not to flare these insects. Spider mites are being seen in cotton now for a while. This we need to be aware.
Spider mite damage
Thomas County Ag 