Cotton in the Carolinas runs the gamut from standing in water, stunted and yellowing to rank and in definite need of growth regulators, and the lack of uniformity promises to make insect control a tough challenge.
North Carolina State University Entomologist Jack Bacheler says stink bugs appear to be present in large numbers so far this year, and this could be a problem, especially for late-planted crops, including cotton.
He notes, “The correlation between higher stink bug levels and damage potential to cotton bolls in wet years and lower potential damage to bolls in dry years appears to hold up reasonablly well. Consider 2013. Stink bug levels so far this year are generally high following our protracted rainy weather, but many areas are now dry and in some cases stink bugs are getting harder to find.”
Bacheler says he spent most of a day recently trying to capture brown stink bugs for a field experiment. The corn, vegetable and tobacco fields yielded only one brown stink bug. However, in the same area the same week, consultants were finding high levels of stink bugs in soybeans.
“Hopefully, most stink bug treatment decisions will be based on levels of internal damage to bolls. The stink bug decision aid web-based app can help with this,” he says.
In South Carolina, some areas of the state have been severely flooded and cotton and soybean plantings were pushed back significantly in some sections, especially in southeastern South Carolina.
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As is the case throughout much of the Southeast, the sporadic nature of the excessive rainfall, in some cases 100-year records for May-July, has left a very non-uniform crop, making for some unusual pest management challenges for growers.
Clemson University Entomologist Jeremy Greene says, “I don’t have to tell you we have a very strange crop out there. We have plants standing in water, either dying or not growing, and we have plants that look pretty good or rank. Most fields are in between those descriptions.
"Just like most growers, we have not been able to get ground equipment through fields here at Edisto Agricultural Research and Extension Center in Blackville, S.C., in a timely manner, so we have some growth issues.”
Greene says rank cotton plants will interfere with delivery of insecticides. In fields with good yield potential, growth regulators are needed to help make insect control more manageable.
“Much of our cotton crop is in the critical protection window for stink bugs (weeks 3-5 of bloom). Growers can use the dynamic boll-injury threshold to manage for stink bugs by week of bloom,” he adds.
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