First we will give an overview of weather conditions, especially since this may be impacting some of our insect and pest control decisions in the coming days.
After a good moisture and rainfall pattern of about 10-14 days ago, our crops have reached a hot-drought stressed condition at present. The situation is worse in the northern area of the state where less rainfall fell during the last thunderstorm period. I saw corn wilted badly in the Tennessee Valley on Tuesday (June 19).
This droughty situation could well impact spray decisions with pests such as aphids and spider mites in the immediate days ahead. Aphids are building state-wide and drought stress plants are where I am more suggestive for chemical controls instead of waiting for the natural fungus.
Tarnished plant bug adults are also being reported from some fields from the Tennessee line in the north to the Florida line in the south. Square retention is dropping, especially in fields in South Alabama that are a couple of weeks into bloom — these would be early-mid April planted cotton.
Also in these some fields, adult brown stink bugs are being reported. We know from past years what stink bugs do to small thumb sized bolls when no larger ones are present.
If present in cotton, stink bugs will feed on small bolls to develop. Knowing this impacts the chemical we may want to choose for TPB control. It needs to be a product that also controls or highly suppresses brown stink bugs.
The best options here would be Bidrin or a high rate of bifenthrin. Aphids in the picture would further complicate the chemical selected. Of the neonic type products, Centric might be the best choice for tarnished plant bug adults, brown stink bugs and aphids.
Three-cornered alfalfa hopper damage is still evident in cotton, in reddish stunted plants that have a girdled and swollen area around the main stem. However, this damage is old now and most plants are too tough for main stem girdling by the three-cornered alfalfa hopper.
The biggest insect news of the week in Alabama was the finding of the Kudzu bug in soybeans in Cherokee County, Ala., on June 21. The kudzu bug had been found in about 25 counties on kudzu, but this was the first find on soybeans.
Alabama growers will want to lean heavily on recent research conducted in Georgia, South Carolina, and North Carolina on this new envasive pest. We need to beef up our scouting on soybeans for this pest – especially the immature stage.
(For more on the situation in soybeans, see Kudzu bugs found in Alabama soybeans ).