Variation of Cyhexatin resistant character in a population of Tetranychus cinnabarinus reared on Dianthus caryophyllus carnation

Abstract

Starting with a colony of Tetranychus cinnabarinus Boisduval reared on carnation and resistant 13.2 times to cyhexatin, the behaviour of the susceptibility through 17 generations of autogamy was observed. After the 7th gene­ration, a reduction in the level of resistance was found, being this reduction of 5.2 times in generation 17th. To observe the behaviour of the resis­tance, the cyhexatin resistant population was crossed with a susceptible one. The F₁ showed a reduction of 6.3 times. The value of the LC₅₀ never reached the level of the susceptible population, but it remained within the values to establish an adequate manage­ment of the pest. The F2, F3, Rc1 and Rc₂ did not show differences in relation to the LC₅₀ of the F₁. The release of susceptible colonies within the resistant populations could be taken as an alterna­tive for the management of the mite with cyhexatin, pro­viding the knowledge on the behaviour in the field is en­larged.