Weather and Insects Affect Late Season Cotton, Soybean and Peanuts

The greatest impact on cotton during the past two weeks has been the lack of rainfall. Drought and intense heat has resulted in the shed of all fruit less than 10 day old bolls from the terminals of plants. This will tend to shorten additional boll production by 2 to 3 weeks and will likely reduce the “top crop” by 200 or so pounds of lint in many fields. Rainfall in the next 7 days would still help fill top bolls that are not mature.

As the result of the above conditions, the insect control season, especially stink bugs, is about over. A few southern green stink bugs can be found in late maturing fields or “swag” areas that remain green in more mature cotton fields. Thresholds for these would be 30-50% internal boll damage on 10-12 day old bolls. A few fields would still profit from stink bug controls.

Tobacco budworms have been extremely low all season but field observations and pheromone traps indicate an increase in the past week or two. Also, bollworm moths are abundant this week in the southern counties of the state.

Soybean Insects- Soybean loopers are at economic levels of 5 or more per row foot in some Gulf Coast area soybeans. Chemical choices (in no particular order) are: Intrepid, Steward, Belt, Tracer and Besiege (Coragen and Karate). Dimilin will give good suppression and long residual. On cotton, the same can be said for Diamond.

Peanut Insects- Scouts reported a mixture of foliage feeding worms in peanuts in Monroe County (S.W. Alabama) about 10 days ago. Many of these were controlled or either they have cycled out by now. This mixture was dominated by bollworm and fall armyworm (grass strain) species. Also in the mix were a few green cloverworms, loopers, and granulate cutworms. Pyrethroids gave nice control of this mix.

Bollworm Pressure Remains Extremely High Across the Coastal Plains of Alabama and Georgia

Bollworm pressure has been extremely high across the coastal plains of Alabama and Georgia for the past two weeks or so. Untreated sentinel plots of conventional cotton in southwest Georgia, southeast and southwest Alabama have been stripped of all fruit during this period. Bollworm moths were still active on August 10th at Headland, Alabama. We are relatively certain most of this population has been the bollworm species because sentinel plantings of tobacco in this same area have had few tobacco budworms present to date. As far as I know, no economic levels of escapes have occurred on varieties with Bt technology.

Aphids Reoccurring in Central Alabama Fields

Aphids have reoccurred in some central Alabama fields in the past week. Their infestation pattern on the plant is distinctly different from that of the aphids that normally occur in June and July. These August aphids are occurring down midways in the canopy while the terminals of the plants are aphid free.

Soybean Loopers in Southwest Georgia

Soybean loopers were discovered in cotton in Seminole county, southwest Georgia, last week. There were only about 2-4 per foot of row which is below treatment levels. However, since this is a little early for loopers to appear, they will have to be watched for in coming weeks.

Fleahoppers and Silver Leaf Whiteflies Reported in Southwest Alabama

After two uneventful weeks with little cotton insect news, several points have been learned this week. Consultants from the Mobile area of SW Alabama voiced that the cotton fleahopper has been their most persistent insect this season. This area also has another fleahopper species in the mix, that being the garden fleahopper. Fleahoppers are not difficult to control but populations can rebound very quickly within 5-7 days. Also in this same area, silver leaf whiteflies (SLWF) are infesting a few cotton fields that are planted adjacent to melon fields. Controls were needed for this insect.

Aphid numbers continue to build, while most insects numbers remain at moderate levels

Insect conditions have not changed greatly in the past week or so. Aphids have continued to build in more fields. All other insects are low to moderate levels (mostly sub-threshold). These include plant bugs (including a few clouded plant bugs coming into the mix), bollworms, tobacco budworms and stink bugs. Most growers do not have enough of a single species to apply controls for. The two biggest surprises at this point in the season are the low number of bollworms and the low number of stink bugs in most fields. Numerous fields of conventional cotton still have less than 2 bollworms per 100 plants. Boll damage to stink bugs is less than 10% in most fields.

Most of the state has had abundant thunderstorms for several consecutive weeks. Cotton yield prospects have improved greatly and, if conditions continue, numerous fields have two bale plus potential. The two biggest limitations we now have are fields with “skippy” stands and too much late maturing cotton.

Later than normal aphid buildup may require more proactive treatments

More fields were reported with aphid infestations last week. Due to this later than normal aphid buildup, growers may want to be more proactive in applying treatments. Stress from aphids, where they are occurring in 2011, is overlapping early to mid boll set. We need to set all the fruit possible in the next two weeks.


Both the brown and Southern stink green stink bug species are present at some level in many fields. Cotton planted in April and up to mid May is already into the third to sixth week of bloom. This means that we should be using a low (10%) internal damaged boll threshold for stink bugs. Growers who chose to treat for aphids should consider stink bugs when selecting their chemicals or tank mixtures.

The flight of corn earworms from corn to cotton usually occurs the week of July 20 in central Alabama. This egg lay may occur up to 7 days earlier in south Alabama and 7 days later in the northern counties. This budworm flight will only be meaningful to those who have planted conventional cotton varieties. Older larvae observed last week were likely from budworm moths that occurred 1 to 2 weeks ago.