Abstract
The development of resistance to bifenazate (resistance ratio of egg=40.3 folds) was found in population of the twospotted spider mite, Tetranychus urticae, collected from rose greenhouses in Chilgok, Gyeongbuk Province in December 2000. This population was selected for 4 years with bifenazate treatment (over 150 times), and showed 248.8 folds increase in resistance as compared to susceptible (S) strain. Inheritance of bifenazate resistant strain (R) and cross resistance of this strain to 9 acaricides were investigated. There were differences of susceptibility in the bifenazate concentration-mortality relationships in F1 progenies obtained from reciprocal cross with the S and R strain $(R{\times}S,\;S{\times}R)$. Degrees of dominance were 0.48 and 0.94 in adult females and eggs of $R{\times}S$ and -0.85 and -0.17 in adult females and eggs of $S{\times}R$, respectively. Inheritance type in the F1 progeny of $R{\times}S$ was incomplete dominant, and F1 progeny of $S{\times}R$ was incomplete recessive. These results suggest that inheritance of bifenazate resistance is controlled by a complete dominance. The R strain exhibited cross resistance to acequinocyl and fenpyroximate in adult females, and amitraz, emamectin benzoate, fenpyroximate, milbemectin, pyridaben and spirodiclofen in eggs. However they showed negatively correlated cross-resistance to emamectin benzoate and milbemectin in adult females, and abamectin in eggs.
2000년 12월 경북 칠곡의 장미재배지에서 채집한 점박이응애를 실험실에서 4년 동안 bifenizate로 150회 이상 도태하여 248.8배의 저항성계통을 얻었다. 이 저항성 계통의 유전과 9종 살비제에 대한 성충과 알의 교차저항성 유무를 조사하였다. 감수성계통 수컷과 저항성계통 암컷을 상호교배$(S{\times}R)$하여 얻은 $F_1$ 우성도는 성충과 알에 대해서 각각 0.48, 0.94로 불완전우성이었으며, $R{\times}S$ 으로 상호 교배하여 얻은 $F_1$ 우성도는 성충과 알에 대해서 각각 -0.85, -0.17로 불완전열성이었다. 이 저항성 점박이응애의 성충은 acequinocyl, fenpyroximate에 대해 각각 9.9, 5.0배의 교차저항성을 나타내었으며, emamectin benzoate, milbemectin에 대해서는 각각 0.14, 0.04배의 역상관교차저항성을 나타내었다. 알은 amitraz, emamectin benzoate, fenpyroximate, milbemectin, pyridaben, spirodiclofen에 대해 각각 22.0, 11.7, 32.3, 16.3, 394.8, 19.5배의 교차저항성을 나타내었으며, abamectin에 대해서는 0.01배의 역상관교차저항성을 나타내었다.
