Field Study and Life History Analysis Monitoring the Sugarcane Aphid, Melanaphis Sacchari, on Various Sorghum Hybrids.

Sorghum (Sorghum bicolor) is a cereal grain crop grown worldwide. National Agriculture Statistics Service reported that in 2014 and 2015 over 6 million hectares of sorghum were planted in the United States. They also reported that in 2014, 137 million bushels were produced in Texas alone. Sorghum is a very important staple crop for many countries and is used as mainly fodder for livestock. Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae), or the sugarcane aphid is a new invasive pest of sorghum (Sorghum bicolor) in southern U.S. The novelty and the speed of invasion of this pest caught the industry by surprise, and today few control options are available. The “honeydew” (sugar water) that they release during feeding causes sooty mold, and combines to jam upon harvesting. In order to develop sustainable control strategies we first conducted a life table analysis of the sugarcane aphid in 5 sorghum hybrids through the use of choice and non-choice tests. Adult aphids laid babies on individual plants, and were all removed except for one baby. The longevity, reproduction, and mortality of the selected babies were recorded. Statistical differences were seen between two hybrids. Genetic resistance to M. sacchari was then evaluated to 16 commercial grain sorghum hybrids in Burleson County, TX on the Texas A&M University farm. Field plots were arranged in a paired-strip plot design with four replications. The 16 grain sorghum hybrids were planted in paired two-row plots, 7.62 meters in length with one plot of each pair serving as an aphid free control. A two-row border separated paired hybrids, this allowed for application of insecticide to aphid free checks. Hybrids known to be susceptible or resistant were included as checks. Data collected weekly included taking an aphid count, spad reading, canopy reflectance reading, crop developmental stage, honeydew visual assessment, temperature reading, and grain yield. Our results represent a first step towards better understanding the biology of this aphid to develop economically and ecologically sustainable control strategies.