Originally published June 16, 2014
Infestations of sugarcane aphids in boot to heading grain sorghum are increasing in Louisiana. Many of these populations start off small and exponentially increase in a span of 5 to 7 days. Pyrethroid applications for midge control can reduce natural enemy numbers allowing sugarcane aphids to reach damaging numbers faster. Honey dew produced by sugarcane aphid feeding will give the crop a glossy appearance and large accumulations will often result in sooty mold growth and harvesting issues later season.
Sugarcane aphids are difficult to control with currently labelled insecticides; however, Louisiana was granted a section18 emergency exemption for the use of Transform 50WG for the 2014 production season. Transform applications should be initiated before grain sorghum becomes heavily infested and producers in Texas are making applications at 30% infested plants with 100 to 250 aphids per leaf present. Use lower aphid numbers with increasing stress due to plant water deficit. This treatment threshold appears to be working for Texas growers; however, these recommendations are not supported by university research due to the recent introduction of this pest to grain sorghum in the United States. Transform applications of 1 oz/acre should be used on medium to high sugarcane aphid populations with the largest gallonage per acre (GPA) feasible for applicators (5 GPA by air or 20 GPA by ground). If 1 ounce applications of Transform are not providing adequate control the rate should be increased to 1.5 oz/acre.
Sugarcane Aphid Damage to Pre-boot Sorghum
Sugarcane Aphids in Sorghum
The LSU AgCenter and the LSU College of Agriculture