The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most important pest species, because it devastates many horticultural and ornamental crops and fruit trees. The resistance ratios calculated for the LC50 value in acequinocyl- and pyridaben-resistant strain was 4,237- and 5,555-fold higher than that of the susceptible strain, respectively. The objective of this study was to evaluate the cross-resistance to several acaricides and to identify the mechanisms associated with acequinocyl- and pyridaben-resistant strain of T. urticae.

The two-spotted spider mite, Tetranychus urticae, is a worldwide agricultural pest that invades a wide range of host crops and rapidly develops resistance to pesticides. T. urticae can be resistant to one acaricide or exhibit multiple resistances or cross resistance to various other acaricides. Acequinocyl inhibits respiration in mitochondria at the ubiquinol oxidation site (Q0) of Complex III of the electron transfer chain. Pyridaben is a METI acaricide that inhibits mitochondrial electron transport at complex I. In this study, we investigated the cross resistance to seven acaricides in acequinocyl- and pyridaben-resistant strain. Furthermore, the frequencies of the I256V and N321S mutations in mitochondrial cytochrome b (cytb) of pyridaben-resistant and fieldcollected strain was analyzed.

The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most important pest species devastating many horticultural and ornamental crops and fruit trees. In the present study, a field strain was collected in January 2001 and has been selected for sixteen years with acequinocyl. The resistance ratio calculated from the LC50 of eggs and adults was 191- and 4,237-fold, respectively. The laboratory-selected acequinocyl resistance (LSAR16) strain was screened with 11 acaricides for cross-resistance. The detoxifying enzyme activities and quantitative real-time PCR analysis were performed in the LSAR16 strain. Crossing experiments revealed that LSAR16 strain was inherited maternally, incompletely dominant and monogenic. Most importantly, we identified two new point-mutations at mitochondrial cytb from acequinocyl resistant T. urticae.

딸기에서 점박이응애에 대한 생물적 방제인자로서 칠레이리응애 평가와 선택독성 약제인 acequinocyl을 효율적으로 이용하기 위해, 시설하우스 온실에 6개의 배드(1.5×3m; 딸기 20주)를 조성한 후 점박이응애를 접종(2011. 10. 5; 20주당 100마리)하였다. 칠레이리응애 처리구, acequinocyl 처리구, 칠레이리응애 +acequinocyl 처리구를 두고 점박이응애와 칠레리응애를 7일 간격으로 조사한 결과, 칠레이리응애+acequinocyl 처리구에서 점박이응애가 가장 효율적으로 방제되었다. 칠레이리응애 처리구에서도 점박이응애의 밀도가 낮게 유지되었으나, acequinocyl 처리구에서는 점차 점박이응애 밀도가 증가하여 약제처리 1달 후에는 처음의 밀도로 회복되었다. 농가포장에서 점박이응애의 밀도가 높았을 때 칠레이리응애 방사 후 acequinocyl 처리가 점박이응애를 효율적으로 방제 할 것으로 평가된다.

Twospotted spider mite, Tetranychus urticae was collected from the rose greenhouse in Gimhae, Gyeongnam province in Jan, 2001. Resistant strain was reared over nine years treated with Acequinocyl (over 400 times), and increased 614 folds as compared to susceptible strain (S). Cross resistance of acequinocylresistant strain adults to eight acaricide was showed high in Cyflumetofen (108 folds) and expressed low in Abamectin (16 folds), Tebufenpyrad (7.6 folds), Fenpyroximate (6.1 folds). Against Chlorfenapyr (0.5 folds), however, showed negatively correlated cross resistance. Synergistic effects with PBO (piperonyl butoxide), an oxygenase inhibitor, DEF (S,S,S-tributyl phosphorotrithioate), an esterase inhibitor, and DEM (diethymaleate), an inhibitor of glutathion S-transferase were also investigated. Synergistic effect showed low in DEM (4.2 folds) but showed high in PBO (12 folds) and DEF (23 folds).