[Effect of temperature on Macrosiphoniella sanborni development]

The development of Macrosiphoniella sanborni was studied at 15-35 degrees C and 80% RH, and the data obtained were used to determine the rate and threshold of its development and the sum of effective temperature. The optimal temperature for M. sanborni development ranged from 22 degrees C to 25 degrees C. After fitting the data to Wang Rusong's model, the development rate V(t) increased with rising temperature. The 2nd and 3rd instar nymphs were found more tolerable to extreme temperature and had higher optimal temperature than 1st and 4th instar nymphs. The temperature tolerance value delta was 6.70 for the 2nd and 3rd instars, and 4.70 and 4.50 for the 1st and 4th instars, respectively. The optimal temperature for the 2nd and 3rd instar was 21.76 degrees C, and the highest development temperature was 40.97 degrees C, while for the 1st and 4th instar, the optimal temperature was 23.76 degrees C and 22.49 degrees C, and the highest development temperature was 39.97 degrees C and 40.56 degrees C, respectively. Calculations with direct optimum estimation method showed that the threshold of development decreased with the aging of nymphs, while the effective accumulative temperature increased. For the 1st, 2nd, 3rd and 4th instar, the threshold of development was 6.93, 5.02, 4.58 and 4.46 degrees C, and the effective accumulative temperature was 26.88, 33.41, 33.63 and 48.49 degrees C x d(-1), respectively.