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• Droughty growing conditions made it easy to distinguish between the “haves” and the “have-nots” of irrigation during the Central Alabama Crops Tour held in mid-August.
AUSTIN HAGAN, Extension Plant Pathologist, left,
and Tom Ingram, Lee County, Ala cotton grower
Little leaf spot
“Because of weather patterns, we haven’t seen much leaf spot. We have seen some white mold in south Alabama, but there isn’t any tomato spotted wilt virus out there. It has pretty much dropped off the map in Alabama in the last three to four years,” he says.
Normally, cotton producers don’t see many foliar disease problems, but that could be changing, said Hagan during the central Alabama tour.
“Over the last few years, there have been issues with potash-related leaf spot diseases in cotton. There have been fungicide trials to try and manage that issue. Basically, if you bring up the potash level, you generally won’t have a problem with leaf spot,” he says.
However, corynespora leaf spot disease has been a problem in Georgia for the past three or four years, particularly in irrigated, no-till cotton, when cotton follows cotton, he says.
“It’s hard to judge how much yield loss might be occurring. But if leaves fall off where squares or bolls are developing, the boll won’t get any larger. It does appear this disease may be an issue.
“We have received samples with moderate to high levels of leaf spot. It has particularly been an issue in Baldwin and Mobile counties, where in isolated fields we’ve already seen 25- percent leaf loss on plants with four or five bolls,” says Hagan.
With dryland cotton, this disease probably won’t be an issue. “One of the problems is that there virtually has been no work done on this disease, other than demonstration plots in southwest Georgia. We’re trying to develop a profile on the disease so we can do some work on it next year,” he says.
Assessing the cotton insect situation in Alabama this year, AU Extension Entomologist Ron Smith says cotton planted from about April 15 to May 15 saw tremendous thrips pressure. It was due mainly to the drying down of wild host plants around the field, along with wheat.
With the loss of Temik still a possibility, he says, early season insect programs will have to be refined.
“As far as plant bugs, nothing happened because dry vegetation around fields couldn’t support a plant bug population,” says Smith.
“But around June 23, we started picking up adult plant bugs in central Alabama. We had a big influx of adult plant bugs in a very short window. I thought we’d see the offspring of those about three weeks later, but it never materialized, and we haven’t seen them since. The heat might have been too much for the immature plant bugs.”