Aphids are small, soft bodied insects that come in a wide variety of colors. Some have wings while others may not. Aphids have piercing-sucking mouth parts which they use to pierce plant tissue and suck out the juices. Damage often appears as yellowing/curling of plant leaves. Extensive leaf injury can reduce hay yields. A new aphid pest has infested sorghum in south, east, and some central Texas areas as well as Mississippi, Louisiana, and Oklahoma and that is the sugarcane aphid. This aphid appears to have switched its host from sugarcane to plants in the sorghum family (grain sorghum, forage sorghum, Johnson grass) the sugarcane aphid showed up in Texas in 2013 and appears as if it is on the move this summer. These aphids are gray to tan to yellow in color. Unlike other common aphid species, sugarcane aphids have dark, paired, tailpipe-like structures, called cornicles, at the rear which contrast distinctively with the lighter body color.
Sugarcane aphids colonize the lower surfaces of lower leaves of sorghum plants first then advance to upper leaves. Small colonies can quickly grow to large colonies and produce large amounts of sticky honeydew. The honeydew can also support the growth of black, sooty mold fungus. Infestations can kill young sorghum plants. Later infestations can prevent gain from forming and cause problems with harvest equipment. The tan to cream colored sugarcane aphids initially colonize on the undersides of leaves near the bottom of plants, then move up the plant as populations increase. When about 40 percent of the plants are infested, it’s time to spray. Plants are considered infested if they have 100 or more aphids on one of the leaves.
To my knowledge, we have not had any confirmed cases of sugarcane aphid in Brown County. However, they have been found in San Saba, Mills, Runnels, and Tom Green Counties in the last two weeks. Ag producers who have possible sugarcane aphid outbreaks in Brown County are asked to report such cases. When populations of sugarcane aphids are increasing rapidly, insecticide applications may be needed. The insecticide Transform WG has been used effectively to control sugarcane aphid in sorghum. It is available in Texas through Section 18 Emergency Exemption Label. The Section 18 emergency label granted by the U.S. Environmental Protection Agency earlier this year for Transform allows for application rates from 0.75 to 1.5 ounces per acre. Only two applications can be used during the growing season, so proper timing and thorough crop coverage are crucial for best results, he said. The pesticide also requires a 14-day interval between application and harvest.
Application Timing: Treat in accordance with local economic thresholds.
Restrictions:
Preharvest Interval (PHI): Do not apply within 14 days of harvest for grain or 7 days of harvest for forage or stover.
A restricted entry interval (REI) of 24 hours must be observed.
Do not make more than two applications per acre per year.
Minimum treatment interval: Do not make applications less than 14 days apart.
Do not apply more than a total of 3.0 oz of Transform® WG (0.09 lb ai of sulfoxaflor) per acre per year.
Label and authorization letter can be found on the Texas Department of Agriculture’s website.