Life history analysis and field study monitoring the sugarcane aphid, Melanaphis sacchari, on different sorghum hybrids

Sorghum (Sorghum bicolor) is a cereal grain crop grown worldwide and a staple crop for many countries. National Agriculture Statistics Service reported that in 2014 and 2015 over 6 million hectares of sorghum were planted in the United States and the market value of grain sorghum of $1.6 billion. They also reported that in 2014, 137 million bushels were produced in Texas alone. Sorghum is used as mainly fodder for livestock.  Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), the sugarcane aphid, is a new invasive pest of sorghum (Sorghum bicolor) in southern U.S. It was first observed in sorghum in 2013 in Texas, but high infestations caused important losses in 2014 in several southern states (Louisiana, Mississippi, and Oklahoma). The “honeydew” (sugar water) that they release during feeding causes sooty mold (decreasing photosynthesis), and combines to jam upon harvesting. The novelty and the speed of invasion of this pest caught the industry by surprise, and today few control options are available. In order to develop sustainable control strategies a life table analysis was first conducted of the sugarcane aphid in five sorghum hybrids. These included both grain sorghum and sweet sorghum hybrids. Genetic resistance was then evaluated to M. sacchari to 16 commercial grain sorghum hybrids in Burleson County, TX on the Texas A&M University farm. Hybrids known to be susceptible or resistant were included as checks. Our results represent a first step towards better understanding the biology of this aphid to develop economically and ecologically sustainable control strategies.