What has been an escalating problem with sugarcane aphid (SCA) populations in the Lower Rio Grande Valley (LRGV) grain sorghum this spring has reversed course as SCA numbers have declined significantly, according to reports late last week, largely the result of treatments in heavily-infested fields.
As early as late March, Extension pest management specialists in the Valley reported a major uptick in SCA numbers, primarily from populations across the Rio Grande in Mexico. Texas AgriLife Extension IPM agent Danielle Sekula says strong winds from the Southwest helped aphids migrate across the border and into Deep South Texas fields.
As temperatures ramped up in the Valley during April, rapid SCA proliferation caused additional northward migration of aphids, spreading into fields outside of the three-county LRGV region.
While recent treatment of fields across the Valley have aided in notable reductions of aphid populations, the opposite is being reported in counties of the Texas Mid-Coast region.
"Sugarcane Aphids are being reported in high numbers across the Coastal Bend. Timely scouting is necessary to control this pest and reduce yield loss," Extension officials in San Patricio County advised through an email alert earlier this week.
Farther up the coast, sugarcane aphid populations are present in sorghum fields in Wharton, Jackson and Matagorda counties, according to reports from Extension IPM specialist Kate Harrell in Wharton.
"I have heard of fields at threshold and being treated in Matagorda County. Populations in Wharton County seem just now to be moving into sorghum," she reports.
Jason Ott, Nueces County Extension agent, reports increasing numbers of sugarcane aphids in grain sorghum in southern areas of the county, especially around Chapman Ranch. But Ott says he has not talked with producers about their latest scouting results.
"I am recommending that producers step up scouting efforts as we are anticipating an increase in sugarcane aphids in our area," he said.
Ott says two reliable tools are available for SCA pest management in grain sorghum, but most producers seem to be favoring Sivanto at this stage in the growing season, largely because of label instructions that allow use nearer to harvest dates. But he says many growers are hopeful it will not be necessary to apply Sivanto because of the increased cost, but if rapid infestation of SCA occurs in the days ahead, he says the cost may well be justified to reduce yields or cause crop losses.
Exceptionally high winds across the mid- and upper Coastal Bend last week caused some damage to cotton, especially in Jackson and Matagorda counties. While wind damage has not been widespread, a few areas suffered from straight-line winds of 50 miles per hour and greater.
Of more concern, however, is increasing pest pressure in some South Texas and coastal area fields.
According to the Texas Boll Weevil Eradication program, the Lower Rio Grande Valley has a total of just over 200,000 acres of planted cotton this year. That represents more acres of cotton than in recent years. Cotton is squaring nicely in the LRGV with reports of an increase in fleahopper infestations in many fields. But overall, Sekula reports low to moderate fleahopper activity across the three-county Valley region.
She warns that fleahopper populations could increase rapidly, and advises producers to monitor cotton currently squaring to avoid damage. In addition, she reports some Valley producers have sprayed some of their fields to reduce problems associated with spider mites. On the brighter side, cotton aphid populations in the Valley have dropped significantly over the last week with most fields having only a few aphids. She credits increased numbers of beneficials with reducing the aphid problem.
In the Texas Coastal Bend, some pest pressure has been reported in cotton, and spot applications have been made to treat for fleahoppers, but overall, pest pressure has not yet been a serious problem. Producers are scouting following reports of bollworms, armyworms, and stink bugs in some fields.
Similar conditions exist in Wharton, Jackson and Matagorda counties in the Upper Coast region where more adult fleahoppers have been reported in cotton, but at numbers below threshold with only a few exceptions.
Cotton producers now have another tool in their arsenal to treat pest in cotton. Texas received approval for a Section 18 use of Transform in cotton to control plant bugs. This label allows for use of the product until the end of October. The rate for plant bug control with Transform is 1.5 to 2.5 ounces per acre, with no more than a total of 8.5 ounces per acre per year used, and no more than two consecutive applications per crop. The label warns not to apply the product within 14 days of harvest, and not to make applications less than five days apart.