Development and survival of Aulacorthum solani, Macrosiphum euphorbiae and Uroleucon ambrosiae at six temperatures

Temperature is one of the most important factors in determining the survival and developmental rate of aphids. The aim of this study was to evaluate the developmental time and survival of the aphid species Aulacorthum solani (Kaltenbach), Macrosiphum euphorbiae (Thomas) and Uroleucon ambrosiae (Thomas) (Rhynchota Aphididae) at six constant temperatures. Tests were conducted on lettuce plants (Lactuca sativa L.) in climate chambers at 16, 19, 22, 25, 28 and 31 plus or minus 1 degree C, 70 plus or minus 10% RH and 12 h photophase. At high temperatures these species showed lower rates of survival than at low temperatures, and at 31 degree C no aphids reached adulthood. The highest survival rates and the shortest developmental times were observed between 16 and 22 degree C. The lower temperature threshold (Tb) and thermal constant (K) for A. solani and M. euphorbiae were 1.09 and 1.05 degree C and 142.9 and 144.9 degrees-day (DD), respectively, while for U. ambrosiae these parameters could not be estimated. The highest survival rate and short developmental time found at 22 degree C indicate that this temperature is optimal for development of A. solani and M. euphorbiae, whereas the optimal temperature for U. ambrosiae is 19 degree C.