Toxicity of Spiromesifen to the Developmental Stages of Bactericera cockerelli (Sulc) (Hemiptera: Triozidae)

Spiromesifen is an insecticide that inhibits the synthesis of lipids and, in Mexico, its use against the Tomato-Potato Psyllid, Bactericera cockerelli (Sulc), on chili pepper (Capsicum annum), tomato (Lycopersicon sculentum) and potato (Solanum tuberosum) began in 2005; however more information is needed to understand its toxicity on this insect pest. The aim of this research was to determine the toxicity of spiromesifen against each of the biological stages of tomato-potato psyllid, its effect on fertility and viability of eggs deposited by treated females, as well as the female preference to lay eggs on treated and non treated plants. The relative toxicity at 95% mortality (highest LC95 value/LC95 value of the respective biological stage) of spiromesifen in egg, nymph 1, nymph 2, nymph 3, nymph 4, and nymph 5 were 517.5; 31316.2; 2950.1; 315.6; 18.2 and 1-fold, respectively. There were no differences in the toxicity of spiromesifen between adult males and females. The number of laid eggs was reduced as the spiromesifen concentration used to treat female increased and egg hatch was reduced in all tested doses. In the no choice test, females deposited 38.6 +/- 2.01 eggs by leaf of non treated chili pepper type jalapeno, while in the treated with 360 mg L-1 we observed 0.3 +/- 0.08 eggs by leaf. In the choice test, the oviposition decreased as the dose increased. There were no eggs on plants treated with 2400 mg L-1 of spiromesifen.