The citrus acreage of Mexico exceeds 532 000 hectares. This area is endangered by the recent detection of the bacterium Candidatus Liberibacter asiaticus in some states and by the wide distribution of the vector Diaphorina citri. The aim of this study was to evaluate the efficiency against D. citri of chemical compounds applied to the soil and foliage in Persian lime. Two field evaluations were made during 2011 with applications of spirotetramat and imidacloprid to foliage and soil, and of spinosad and avermectin only to foliage. In the first evaluation, the spirotetramat (400 mL/ha) and the imidacloprid (300 mL ha-1), applied to foliage, caused a decrease of nymphs of 78.8%-93.54% three days after the application. The Imidacloprid (300 mL ha-1), applied to the soil, the spinosad (0.1 L ha-1), and the avermectin (0.1 L ha-1), had 69.8%, 70.6% and 61.6% less nymphs than the control treatment. In the second evaluation, imidacloprid, applied to the foliage, decreased the population of nymphs in shoots by 81.9%.The lowest average of nymphs per shoot in various sampling dates was obtained with the spirotetramat and imidacloprid treatments applied to foliage; 89.6% and 87.5% less than the control, respectively. Of the products evaluated, the spirotetramat and the imidacloprid, when applied to foliage, exerted the greatest effect against D. citri.

La superficie de cítricos en México es superior a 532 mil hectáreas. Esta área se encuentra en peligro por la reciente detección de la bacteria Candidatus Liberibacter asiaticus en algunos estados y por la amplia distribución del vector Diaphorina citri. El objetivo fue evaluar compuestos químicos aplicados al suelo y follaje contra D. citri en lima persa. Se hicieron dos evaluaciones en campo durante 2011. Con aplicaciones de espirotetramato e imidacloprid al follaje y al suelo y spinosad y avermectina sólo al follaje. En la primera evaluación, tres días después de la aplicación, el espirotetramato (400 mL/ha) e imidacloprid (300 mL ha-1) aplicados al follaje ejercieron una disminución de ninfas de 78.8% y 93.54%. El imidacloprid (300 mL ha-1) aplicado al suelo, spinosad (0.1 L ha-1) y avermectina (0.1 L ha-1), tuvieron 69.8%, 70.6% y 61.6% menos ninfas que el testigo. En la segunda evaluación, el imidacloprid aplicado al follaje disminuyó 81.9% la población de ninfas en brotes. El menor promedio de ninfas por brote en diversas fechas de muestreo se obtuvo con los tratamientos de espirotetramato e imidacloprid al follaje, 89.6% y 87.5% menos que el testigo, respectivamente. De los productos evaluados el imidacloprid y espirotetramato aplicados al follaje ejercieron mayor efecto contra D. citri.

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 jalapeño, 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.