• Korean journal of applied entomology
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• v.47 no.3
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• pp.227-235
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• 2008

Development of T. urticae was studied on the leaves of eggplant grown in hydroponics with silica contents of 0 mM, 1.7 mM, and 5.1 mM. As the levels of sllica increased, those of N, P, K, Ca, and Mg decreased and those of Si increased. While contents of calory, crude protein, carbohydrates, and vitamin C decreased, those of ash, fiber, and sugar increased. Biomass and content of cholorophyll decreased as the level of silica increased while leaves became thicker. Laboratory leaf disc tests provided with various silica levels revealed that feeding preference of T. urticae was the highest at 0 mM and the lowest at 1.7 mM. The oviposition preference decreased as the levels of silica increased, on the lower leaf appeared to hinder the feeding and the oviposition of T. urticae. The development slowed down both in female and male. Adult life span of female shortend as the silica level increased and that of male was the longest as 5.7 days at 0mM and the shortest at 1.7 mM. Oviposition period also shortened as the silica content increased. The number of eggs laid was the most as 86.3 at 1.7 mM while average oviposition per day was the least as 77 at 0 mM. No differences in hatchability was detected whereas the ratio of sex was the highest as 0.71 in favor of female at 0mM. $R_o$ and T decreased as the levels of silica increased. Rm and $\lambda$ was the lowest at 5.1 mM while Dt was the longest as 1.8271 at 5.1 mM and the shortest as 1.6991 days at 1.7 mM. Silica content in eggplant turned to affect the development of T. urticae, however, it deterred T. urticae from feeding and oviposition and the rate of increase tended to decrease due to lesser nutrients in the eggplant leaf.