• Korean journal of applied entomology
• /
• v.35 no.3
• /
• pp.260-265
• /
• 1996

A field colony of the two-spotted spider mite, Tetranychus urticae Koch, was selected with tetradifon for 4 mousing whole-plant residual method. This strain showed 371-fold resistance to tetradifon. The log dosehatchability lines of $F_{1}$ eggs(RS cross; Td5female$\times$Smale, and SR cross; Sfemale$\times$Td5male) were closer to the line of the resistant colony than to that of the susceptible. These differences could be due to cytoplasmic inheritance or maternal effect. The estimate of dominance index (D) for the $F_{1}$ eggs of RS cross was 0.998 and that for $F_{1}$ eggs of SR cross was 0.262. This indicates that tetradifon resistance is completely dominant in RS cross and incompletely dominant in SR cross. Td5 strain exhibited high levels of resistance to clofentezine, benzoximate, and chlorfencon, and no cross resistance to fenazaquin, pyridaben, flufenoxuron, tebufenpyrad, and fenothiocarb.

• Korean journal of applied entomology
• /
• v.34 no.4
• /
• pp.328-333
• /
• 1995

Susceptibilies of tow-spotted spider mite (Tetranychus urticae Koch) collected at 6 locations were assessed to 15 acaricides. The response to acaricides were almost similar in female adults and eggs. There were considerable difference in susceptibility depending on the acaricide treated and the region from which the population was collected. The population showing resistance ratio of more than 20 with respect to certain acaricide was regarded as a resistant population to the acaricide. The resistant populations in terms of female adult were as follows: Suwon population to azocyclotin, cyhexatin, and fenbutatin-oxide; Taejon population to dicofol and fenbutatin-oxide; Chongju population to dicofoll Chinju populatin to cyhexatin, dicofol, and fenbutatin-oxide. The resistant populations in terms of egg were as follows; Suwon population to bifenthrin, clofentezine, hexythiazox, and tetradifon; Kunwi, Chongju, and Kwangju populations to bifenthrin; Taejon population to amitraz and bifenthrin; Taejon populatin to amitraz and bifenthrin; Chinju population to amitraz, bifenthrin, clofentezine, dicofol, and tetradifon. However, the female adults and eggs of all field populations were susceptible to abamectin, chlorfenson, and fenpyroximate. This tendency was also reported previously in the susceptible strain from laboratory.

• Korean journal of applied entomology
• /
• v.33 no.4
• /
• pp.230-236
• /
• 1994

Dicofol susceptible two-spotted spider mite(S) which was selected by 150 times of dicofol treatment showed 27 5-fold increase in resistance as compared to S strain. Inheritance of resistance and crossresistance in selected strain($R_d$) were investigated. There were differences oi susceptibility in the dicofol concentmtion-moltaliity relationships between $F_1$ progenies (R♀, XS♂, R♂, XS♀) obtained from reciprocal cross with the S strain and $R_d$, strain. Degree of dominance of the $F_1$ progenies (R♀, XS♂, R♂, XS♀) were -0.29 and -0.72 in adult females and -0.42 and -0.93 in adult males, respectively. These results suggest that inheritance of dicofol resistance is controlled by an incomplete recessive. $R_d$ strain exhibited a high level of cross resistance to amitraz, and also showed cross resistance to pyrethrotd acaricides, acrinathrin and bifenthnn. $R_d$ strain showed non-cross reslstancz to abamectin, chlolfenson, clofentezine, cyhexatm, fenbutatin oxlde, fenpyroximate, hexythiazox, monocrotophos, propargite and tetradifon, but negatively correlated cross-resistance to azocyclotin and fenbutatin oxide belonging to tin acaricides.