As Lower Rio Grande Valley farmers in deep South Texas continue their fight against an explosion of white sugarcane aphids in sorghum fields, Jeff Nunley, executive director of the South Texas Cotton & Grain Association (STCGA) in Victoria, has issued a warning to Coastal Bend sorghum growers that the pest can quickly move into coastal sorghum fields with little advance notice.
Nunley reports a producer from the Corpus Christi area last week reported a heavy infestation of sugarcane aphids in his sorghum. The grower warned other producers to scout fields regularly, especially during flagging and head emergence. In his case, the grower went from finding no aphids in his fields on Monday to a full-blown infestation by Wednesday's scouting.
Last week, Jason Ott, CEA-Ag/NR, Texas A&M AgriLife Extension Service in Nueces County, says the new aphid was first observed in numerous fields across parts of the county around May 16, but generally in low populations of five or so aphids on a leaf with only 1 percent to 5 percent of the leaves infested. Some fields, however, had about 50 percent of leaves infested. But on May 20, the first grower report of heavy infestations in a field came in and a sample dropped by the Nueces County AgriLife office had "hundreds of aphids on it and the grower reported that it was representative of about 20 percent of the plants in his field."
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The new aphid was discovered late last year damaging grain sorghum in Texas, including Nueces County, and even in neighboring states. In his weekly newsletter Ott reported infestations were heavy, often with hundreds of sugarcane aphids per leaf. Leaves became sticky and shiny from honeydew and coated with sooty mold fungus, which hampered harvesting operations.
While AgriLife agents and farmers were expecting a return of the aphids this spring, heavy infestations like those discovered in the lower Valley earlier this month caught them by surprise.
Prepared for explosion
Texas AgriLife Extension Integrated Pest Management specialist Danielle Sekula-Ortiz in Weslaco said farmers and officials were prepared for an overnight explosion of white sugarcane aphids in Cameron and Hidalgo counties last week.
"Practically overnight we saw a huge jump in aphid numbers in sorghum fields," she said. "I have never seen anything like this before."
Last week a special meeting in Weslaco attracted more than 170 growers, crop consultants, AgriLife officials and several pest management specialists from Mexico who received updates on the extreme spread of aphid populations in sorghum across the region.
"We even saw movement of the aphids into sugarcane and corn fields as well," Sekula-Ortiz reported.
She said infestations south of the border are heavy and reports entomologists in Mexico are asking for cooperation of officials on both sides of the border to fight a problem they say is spreading rapidly into other areas.
San Patricio County AgriLife agent Bobby McCool reports sugar cane aphid infestations in his county. He advises if sorghum is beginning to head out, growers need to scout fields carefully and often. He says if you discover any sticky substance on sorghum leaves, then you will probably find aphids in large numbers on the underside of the leaves.
Pest management specialists say the white sugarcane aphid is translucent at early stages with a pale yellow tint and becomes a little darker yellow as they mature, but they warn growers should not confuse the new pest with the more traditional yellow sugarcane aphid that has been around for a number of years. They warn the new, smaller white sugarcane aphid is more destructive and say populations can grow rapidly once they move into a sorghum field.
While a treatment threshold has not been set, once aphids are discovered on 30 to 40 percent of plants in a field, producers should spray with the recently approved Transform WG. More than one spraying will likely be required in heavily infested fields, and a third treatment may be necessary to prevent heavy crop losses.
On June 4, Texas A&M AgriLife Extension Service and the Nueces County Crops Committee will host a crop tour highlighting area crop production and applied research demonstration being conducted by AgriLife Extension in cooperation with area growers. Officials say this will be an excellent opportunity for producers to obtain hands on information about several emerging issues affecting crop production this year, specifically the current sugarcane aphid invasion.
For more information about the crop tour, contact the Nueces County Extension Office in Robstown at 361-767-5223.