With dryland cotton defoliation near complete, Rio Grande Valley (RGV) cotton harvest is now underway with irrigated cotton not far behind. Corn and grain sorghum harvest is nearing completion in all fields in the Rio Grande Valley except for sorghum crops in lower Cameron County.

John Norman, editor of Texas AgriLife’s Pest Cast, the Valley’s local weekly crop newsletter, reports a week of slightly cooler temperatures have helped cotton and grain sorghum crops that had been suffering under the hot South Texas sun. He said harvest is slightly earlier this year because of early spring planting and because of an exceptionally warm early summer growing season.

Rain showers were sporadic last week in the RGV with light rains falling in most fields and a few random heavy showers reported.

“Any significant rain now would jeopardize the last of the grain sorghum and possibly 95 percent of the cotton crop. Harvests of corn and grain sorghum continued [last week] and now cotton is underway,” Norman writes.

Norman says much of dryland cotton was ready or near ready for defoliation by the end of this week. Considerable defoliation had already been reported by the end of last week and the trend continues. Some harvesting was completed in a few fields by the end of last week and many more dryland fields were ready for harvest by the end of this week. Percent open boll counts in the Valley ranged from 35 to 100 percent in dryland fields, while the overall trend was about 50 to 0 percent open bolls.

Some irrigated cotton fields were also ready for defoliation by the end of the week and many more are expected to be ready by next week. Norman says the hot weather was driving all fields toward a quicker finish this year and some growers were moving up schedules to accommodate earlier defoliation. Open boll counts in irrigated fields ranged from 0 percent to just over 70 percent as of July 12. The overall percentage of open bolls in irrigated fields in the Valley was about 10 to 50 percent.

Grain sorghum harvest in the RGV is nearing completion, but extreme heat and generally dry conditions have lowered yields. Pest pressure also increased in recent weeks and a few heavy showers came too late to benefit some sorghum fields and delayed harvest in a few more.

“Pests of concern [in cotton] last week were primarily whiteflies and Verde bugs. The only changes in whiteflies seemed to be the increasing numbers in all fields. As this season starts toward the final round up, the only whitefly control of interest for many growers is defoliants,” Norman reported.

Most fields that had early and thorough coverage with the proper insecticides have had lower whitefly infestations than others, Norman said. However, as this season has progressed, re-infestation by extreme numbers of whiteflies moving from other crops and matured cotton fields has led to serious consideration about how much more money can be put into whitefly control and how much benefit there will be.

Norman says it is not the first year for late whitefly infestations and warns producers to weigh the cost of late season spray applications before committing to additional production costs. But he warns that for fields with a large percent of the crop in smaller bolls continued insecticide application may be a good decision.

Also of late season concern is the large number of leaf-footed bugs reported in many Valley fields in recent weeks. He advises growers to check the fields that are susceptible and treat when large squares and small bolls are damaged. So far, leaf-footed bugs have not invaded cotton in “huge numbers.”

Valley boll weevils are on a slight increase this week and producers should continue to scout fields regularly for increasing numbers.