What is in this article?:
- Stink bug complex taking spotlight in Alabama cotton fields
- Treatment decisions in cotton
• One last thing I will mention today is that, in the past, stink bugs seem to cause more internal boll damage in wet seasons than in dry seasons.
• That being the case, and unless the weather changes, we need to be extra cautious of stink bug damage to cotton in 2013.
Treatment decisions in cotton
Back to cotton. Here is how we suggest making treatment decisions.
First, select a minimum of 25 10 to 12 day old bolls that are still soft to the touch and can be crushed by hand. Select more bolls from at least two locations from larger fields. Crush these bolls and observe for internal injury.
Note, it may make this process faster by first separating the bolls with external feeding signs from those that have none.
First, crush the bolls with external feeding only and determine the percent that have internal injury. If a threshold is reached, then the remainder of the bolls with no external feeding signs will not need to be crushed.
Internal damage may consist of one or more warts on the inside of the boll wall, damaged seed or stained lint.
Second, the decision maker needs to know how long that particular field has been in the blooming stage. Most stink bug injury and loss is coming during weeks three though five or six of bloom. This is the period when most harvestable bolls are being set.
In Alabama, I suggest using a 10 percent internal damage threshold during weeks three though six of bloom.
An insecticide application will usually suppress stink bug numbers for seven to 10 days unless a field borders another untreated crop with high numbers of stink bugs. If has been my experience that stink bugs do not move rapidly across fields like plant bugs as they re-infest. The first four to 10 rows adjacent to corn or peanuts seem to get most of the migration initially.
In our heaviest stink bug years, cotton in the Coastal Plains of the southeast have required up to four applications. Under most conditions however, only two or three sprays may be warranted.
One last thing I will mention today is that, in the past, stink bugs seem to cause more internal boll damage in wet seasons than in dry seasons. That being the case, and unless the weather changes, we need to be extra cautious of stink bug damage to cotton in 2013.