The harvest tool of choice for many South Carolina cotton producers in 2002 was a Bush Hog, giving some indication as to the general condition of the crop.
“This past year was one we'd all like to forget,” says Mitchell Roof, Clemson University Extension entomologist. “We didn't have enough rain to make a decent crop from May 1 through Aug. 24. Then, from Aug. 25 through Sept. 3, we received about 6.5 inches of rainfall.”
The rains came, he adds, at the same time bolls were opening, causing hard lock and poor quality and yields. “Rain prevented our cotton growers from harvesting in a timely manner. Of about 300,000 acres planted, we harvested about 186,000 acres,” said Roof at the recent Southeast Cotton Conference in Rocky Mount, N.C.
Insect pressure in South Carolina cotton was “about the same as usual” in 2002, he says.
“The exception might have been bollworm populations. They were at levels we haven't seen for some time now. We started out the season seeing a few budworms, but we didn't see many more during the remainder of the year. Beet armyworms — which were almost non-existent in 2001 — staged a revival in 2002. Some fields were sprayed as many as three times for beet armyworms,” says Roof.
Stink bug pressure was low in South Carolina this past year, and aphid pressure was about the same, he says. A few problems were reported with grasshoppers and false chinchbugs, he adds.
South Carolina growers saw the third field generation of bollworms this past year, says Roof, after about three and a half years of low pressure.
“We began doing pyrethroid resistance work in 1986 and 1987,” he says. “Even though resistance jumped back up in 1996, we're starting to see a lower survival rate from our pyrethroid tests. In 2002, we had about 13 percent survival. So we feel like we're holding the line now with pyrethroid resistance.
“With Bt cotton, we'll be applying fewer pyrethroids, so we should be lowering our risk of developing resistance,” says Roof.
The entomologist also reviewed tests where cotton seed treatments were compared to foliar sprays and Temik at planting. The tests consist of early and late planting dates — April 29 and May 23. Thrips pressure was much heavier in the early than in the late planting.
“The adult thrips count was about as high on the May 23 planting as on the April 29 planting, but we had fewer nymphs developing on the late planting. If you're going to use seed treatments in South Carolina, you're probably safe in later plantings. I wouldn't try it on early plantings because you don't have a long enough residual.
“There were no significant differences in yield, even though almost all of the plants were killed in a lot of the plots. There still was enough plant out there to come back and make a decent yield. Even the untreated made almost 350 pounds per acre. The untreated looks as good as anything in the late planting.”
Roof also reviewed the second generation transgenic cotton varieties or Bollgard II. “Worms will be relegated to secondary pest status with Bollgard II. Beet armyworms, bollworms, fall armyworms will be secondary. We'll still get into problems with bollworms if we wipe out our beneficial insects. Bollard II, by and large, will put us in a good situation.
“Stinkbugs and maybe plant bugs will become our primary pests, and that probably already is the case. Aphids probably will stay the same or the pressure may be a little less.”
Boll weevil eradication, says Roof, paved the way for the effective use of transgenic technology.