Influence of different fertilizer types on life table parameters of citrus red mite, Panonychus citri (Acari: Tetranychidae)

Citrus red mite, Panonychus citri (McGregor) is an important pest of citrus. In order to assess the effect of different fertilizers applying in citrus on this mite, the biological characteristics on the young citrus trees treated with 3 kinds of fertilizer, organic, chemical and compound (mix of organic and chemical fertilizer) were monitored in a thermostatic room. The immature durations were not affected by different fertilizer treatments. However, the survival rates of the immature stages were significantly higher on compound fertilizer and organic fertilizer than on chemical fertilizer. The fecundity of female mites reared on compound fertilizer citrus was also significantly higher than chemical fertilizer. The pre-oviposition period of females reared on compound fertilizer treated citrus was significantly shorter, and the longevity of males was significantly longer than organic fertilizer. Overall, the mites reared on compound fertilizer treated citrus had the highest net reproduction rate (Ro), index of population trend (I), intrinsic rate of increase (rm), finite rates of increase (λ) and shortest mean generation time (T) comparing with other treatments. The results of nutrient composition determination of citrus leaves treated with three fertilizer treatments showed that the leaves of compound fertilizers contained the highest N, P content and N/K. As P has no positive or direct influence on most phytophagous insects and Acaridae mites in previous studies, the compound fertilizer is beneficial to the optimum population growth of citrus red mite may be closely related to the two indexes, N content and N/K.