Wednesday, July 27, 2011

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.

Monday, July 18, 2011

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.

Monday, July 11, 2011

Tarnished plant bug, aphid, tobacco budworm and fall armyworm numbers on the increase

Tarnished plant bug adults were found in numerous fields in western Alabama (Lamar County) on Friday (July 8). Pin head square loss was minimal (less than 5%) and very few immature plant bugs were found. This would indicate that adults had moved into cotton fairly recently. However, this is a situation where damage could increase rapidly if controls are not applied.

Several calls were received late last week about increasing aphid populations in some fields. Aphids are late developing this season, which means they also could be late crashing from the fungal disease. This being the case, the peak aphid stress will come during the early boll set window. Growers may find it best to apply aphid controls and prevent plant stress at this stage of maturity.

Heavy tobacco budworm damage has been occurring on sentinel plots of conventional cotton in SW Georgia for the past week. Growers with Bollgard II and Widestrike can sleep well at night knowing that their investment in technology is working to near perfection.

The “grass” strain of the fall armyworm is now damaging pastures and hay crops in several south Alabama counties. This strain will also feed on peanut foliage but will not feed on cotton.