Volume 41 (2006) Issue 3 Pages 383-387
The citrus psyllid Diaphorina citri Kuwayama transferred huanglongbing (HLB) are distributed in the southern Islands (Yaku, 30°20′N, 130°30′E) of Japan. To predict the northern limit of the spread of the insect, I examined temperature-dependent development and determined the developmental zero of the insects in a laboratory. Eggs and nymphs were reared at temperatures of 15.0 to 32.5°C at an interval of 2.5°C with 16L : 8D on shoots of orange jasmine, Murraya exotica L. Nymphs at 15.0°C fail to develop to adults, and the mortality of those at 32.5°C increased. The incubation period decreased at higher temperatures, varying 15.0 to 2.5 d. These nymphs became adults in 36.3 d at 15.0°C and in 10.7 d at 30°C, but 16.8 d at 32.5°C. The developmental zero and effective accumulative temperatures were 13.66°C and 46.93 d-degrees in the egg group, 11.56°C and 192.27 d-degrees in the nymph group, respectively. Based on these results and winter temperatures, the northern limit of nymphal overwintering of the psyllid in Japan was predicted: the northern limit may be off the southern shores of Kyushu Island, southern Japan, and ca. 31°N.