The toxicities of 37 commercial pesticides for citrus pests were evaluated to N. fallacis. Eight fungicides (difenoconazole, imibenconazole, azoxystrobin, dithianon, fluazinam, procymidon, strep-tomycin, tribasic copper sulfate), three insecticides (dichlovos, imidacloprid, thiamethoxam) and four acaricides (milbemectin, tetradifon, dicofol, spirodiclofen) had lower effect to the hatchability of eggs N. fallacis. Six fungicides (propineb, difenoconazole, imibenconazole, azoxystrobin, dithianon, procymidon) and three acaricides (bifenazate, tetradifon, spirodiclofen) showed lower contact toxicity to adult N. fallacis. The secondary toxicity of 26 pesticides to N. fallacis adult were evaluated. Two fungicides (fluazinam, streptomycin) and 3 acaricides (machine oil, cyhexatin, halfenprox) showed low toxicity when the prey (eggs of spider mite) was treated with pesticides.

Predation of Neoseiulus fallacis was observed for biological control of Panonychus citri that is one of the major insect pests on citrus. The daily predation of development stages of P. citri by an adult female of N. fallacis were 20.1 eggs, 26.1 larvae, 18.2 protonymphs, and 7.4 deutonymphs at 25℃. The daily predation of P. citri eggs by N. fallacis was observed under different temperatures. The predation was increased as the temperature rise. At this time, ratio of eggs production of N fallacis after predation of P. citri eggs (number of eggs N. fallacis/number of eggs P. citri consumed by N. fallacis) was 0.09. The daily predation of P. citri eggs by N. fallacis was 21.1, 17.3, and 16.7 on the different arenas (diameter: 20, 40, and 60 ㎜), respectively. The predation was decreased as the arena of the leaf increase. The functional response of N. fallacis to P. citri showed Holling"s Type Ⅱ response: the consumption of prey by N. fallacis increased as the density of prey increase but increasing rate was gradually reduced. As the result, it seemed that N. fallacis can be use for biological control of P. citri.