Effects of Temperature on Sugarcane Aphid, Melanaphis sacchari Life History on Three Different Host Plants

Sorghum, Sorghum bicolor (L.) Moench, is one of the most important crops in the world. Since 2013, sugarcane aphid, Melanaphis sacchari has become a perennial and significant pest in the southern United States. It can develop on multiple grass hosts but does not appear to survive winter temperatures in the U.S. except in southern Texas. Insects depend on temperature and nutrition to develop and reproduce. The rate of aphid development and reproduction increases as temperature increases until it reaches a maximum temperature where development slows because of metabolic stress. Laboratory experiments were conducted at seven different constant environmental temperatures (5, 10, 15, 20, 25, 30, 35 °C) on three different host plants, sorghum, Johnsongrass, and Columbus grass. Longevity, fecundity, number of nymphs per day, reproductive period, and intrinsic rate of growth were measured. At 5 and 35 °C, reproduction did not occur on any host plant. Longevity was maximum at 15 °C and decreased with increasing temperatures. Reproduction was highest at 25 °C on sorghum and Johnsongrass, and at 20 °C on Columbus grass. The supercooling point (coldest temperature at which survival is possible) was also determined for nymphs, adults, and winged adults of SCA and was found to be between -22 °C and -25 °C. The results of these experiments suggest that alternate host plants support aphid survival but with limited reproduction. Extreme low and high temperatures also affect strongly SCA survival and reproduction.Entomology and Plant Patholog