In recent years, the outbreaks of sugarcane aphids, Melanaphis sacchari (Zehntner) (Hemiptera: Aphididae) have threatened the profitability of sorghum (Sorghum bicolor L. Moench) in much of the U.S., including the Texas Panhandle. For an effective and timely management to minimize economic losses associated with this pest, understanding the population dynamics of sugarcane aphids and their impact on the host plant is very important. Herein, greenhouse experiments evaluated the life history parameters of sugarcane aphids feeding on susceptible and resistant sorghum across several growth stages. Further, field experiments estimated the economic injury of sugarcane aphids in sorghum infested after anthesis. Surveys of commercial sorghum production fields collected data on the timing, severity, and the duration of sugarcane aphid infestations in the Texas Panhandle. The data showed significant effects of levels of genetic resistance and growth stage on several life history traits and demographics parameters of sugarcane aphids. Specifically, aphid population growth was enhanced on susceptible sorghum in the late reproductive stages compared to early vegetative stages. A range of economic injury levels (EIL) were estimated for the aphids infesting the sorghum during or after anthesis stage, with the average EIL of 309 aphids per leaf in 2018 and 191 aphids per leaf in 2019. It was also found that the rate of aphid population growth reached exponential stage within two weeks of their initial colonization, particularly if sorghum was at the anthesis stage. These findings will be useful to sorghum growers and will contribute to reduction in the economic losses caused by the sugarcane aphids.
