Influence of host plants and some leaf contents on biological aspects of Tetranychus urticae Koch (Arachnida: Acari: Tetranychidae)

Abstract Background Phytophagous mites infest most host plants as vegetable, field crops, and ornamental plants. Tetranychus urticae spend most of its life cycle on plant, especially on leaves, and it causes serious damage. The development periods and reproduction of T. urticae are influenced by characteristics for host plant. Purpose of the study To know the effect of host plant on Tetranychus urticae in order to recognize the most suitable hosts for increasing population Tetranychus urticae to be used as food for the mites, as a bio-control agent against different pests. Results The results revealed that the hosts affected significantly on incubation period. Significant differences were found among different host plant leaves for longevity, life span periods and average oviposition period of T. urticae under controlled temperature (28.5 ±2 °C) and relative humidity (76 ±5 %). Average of the reproduction rate per female was higher when T. urticae was reared on leaves of mulberry, while the percentage of hatchability was highest when the females were fed on leaves of mulberry. The sex ratio was higher when it was fed on leaves of castor bean. Nitrogen content in host plant leaves varied, and differences were found between three host plants in concentrations concerning phosphorus, potassium, and total chlorophyll. The correlation between longevity period and nitrogen was highly significantly positive in the case of sweet potato, while the correlation between the duration spider mite life cycle and nitrogen content and the correlation between longevity periods with potassium were significantly positive in castor bean. Conclusions Total immature stages and life cycle were shortest when spider mite was fed on mulberry leaves. The greatest values of reproduction rate and hatchability were on mulberry leaves than on other crops and followed by castor bean. Sex ratio of T. urticae was highest on castor bean leaves. Developmental and reproduction rate of T. urticae are influenced by tissue nutrient content for host plant.