柑桔全爪螨（蜱螨亚纲：叶螨科）在梨树上季节性发生影响种群动态

柑桔全爪螨为害梨树时春夏种群密度极低但随后却突然爆发，形成一年之中只有秋季一个高峰期之发生规律，这与其在柑桔上一年之中两个发生高峰期的发生特点形成鲜明对照。为阐明柑桔全爪螨在梨树直的这种季节消长规律之成因，本采用对比研究方法分析研究了该螨在梨叶和柑桔叶一年之中的产卵率，成活率以及卵的孵化率等生态学习性。结果表明产卵率在梨叶与柑桔叶之间全年均无显差异；然而其在梨叶上的成活率以及卵的孵化率在八月之产明显低于其在柑桔叶上之值，且差异显或极显，但八月之后以上各项指标在梨叶和柑桔叶上均无显差异。

SEASONAL PERFORMANCE AFFECTING POPULATION DYNAMICS OF CITRUS RED MITE, PANONYCHUS CITRI (MCGREGOR) (ACARI: TETRANYCHIDAE), ON PEAR

The population of the citrus red mite, Panonychus citri (McGregor), does not increase on pear from spring to mid summer but thereafter increases abruptly. To elucidate this phenomenon, we compared the performance of the mites on pear leaves with that on citrus leaves, at different time throughout the pear growing season. No significant difference was detected between the oviposition rate on pear and that on citrus throughout the season. However, the survival rate of ovipositing females that had fed on pear and the hatch rate of eggs laid by those females were significantly lower than those for females that had fed on citrus, until August. However, no significant difference was observed thereafter. The results showed that the decline of the population of citrus red mite before autumn is due to the high mortality of adult females that had fed on pear leaves and the low hatch rate of the eggs produced by those females.