Bionomics of Tetranychus urticae Koch on Eggplants under Various Silicate Regimes in Controlled Environment

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.

시설 재배 가지에서 규소 시비 수준에 따른 점박이응애의 생물적 특성

규소를 0, 1.7, 5.1 mM 수준으로 재배한 가지 잎을 먹이로 점박이응애의 발육을 조사하였다. 규소 시비수준이 증가함에 따라 식물체내 N, P, K, Ca, Mg 함량은 감소하였으나 Si의 함량은 증가하였다. 규소 시비수준이 증가함에 따라 칼로리, 조단백질, 탄수화물, 비타민C 등은 감소하였고, 회분, 섬유소, 설탕 등은 증가하였다. 수량과 엽록소는 규소 시비수준이 증가함에 따라 감소하였고, 잎 두께는 두꺼워졌다. 식이선호성은 0 mM처리에서 가장 높았고, 1.7 mM처리에서 낮았으며, 산란선호성은 규소함량이 증가할수록 줄어들었다. 발육율에 있어서는 암컷과 수컷 모두 감소하는 경향이었다. 암컷 성충기간은 규소함량이 증가함에 따라 짧아졌고, 수컷은 0 mM처리에서 5.7일로 가장 길고, 1.7 mM처리에서 짧았다. 산란기간도 규소함량이 증가함에 따라 짧아졌다. 산란 수는 1.7 mM처리에서 86.3개로 가장 많았고, 일일 산란수는 0 mM처리에서 7.7개로 가장 적었다. 부화율은 처리 간에 차이가 없었고, 성비는 0 mM처리에서 0.75로 가장 높았다. $R_o$와 T는 규소수준이 증가할수록 감소하였고, $r_m$과 $\lambda$는 5.1 mM이 가장 낮았으며, DT는 5.1 mM이 가장 높은 1.83일, 1.7 mM이 가장 낮은 1.70일이었다. 식물체내 규소함량은 점박이응애의 발육에 영향을 미쳤다. 그러나 점박이응애의 기피현상이 있었고, 엽내 영양물질의 감소로 점박이응애의 증가율이 감소되는 경향이었다.