Eficácia de inseticidas e formulações de iscas tóxicas sobre Ceratitis capitata (Wiedemann, 1824) (Diptera: Tephritidae)

Abstract

The Mediterranean fruit fly, Ceratitis capitata (Wiedemann, 1824), is a key pest in world fruticulture, causing damage to all fruit species of economic importance in Brazil. The management of this pest is done using insecticides belonging to the organophosphorous, pyrethroids and spinosyns chemical groups which are used in cover sprays or toxic baits formulations, mixing insecticides with a food attractant, hydrolyzed protein or sugarcane molasses. The use of toxic baits is one of the tools for the management of this species, especially during the pre-harvest period, when fruit growers face restrictions on the use of insecticides in cover sprays. The objectives of this work were: a) to develop a methodology for the evaluation of toxic bait formulations in the laboratory; b) verify which toxic bait formulations are more efficient in a dry environment and under simulated rainfall; c) To know the effect of insecticides of different chemical groups on adults by contact or ingestion, on larvae and in a toxic bait formulation and d) to evaluate the efficcacy of ready-to-use toxic baits Gelsura® and Success® 0.02CB applied in areas of fine grapes tables (Vitis vinifera L.). All the factors evaluated for determination of the methodology had influence on the lethal time. It is suggested the use of five to eight days old insects after emergence, from larvae raised in artificial diet, deprived of feeding for 12 hours, providing the toxic bait Success® 0.02CB alone for a minimum period of four hours. Lethal time 50 (LT50 in hours) of the toxic baits was: 2.32 (Gelsura® at 4,000 mg.L-1), 4.26 (Gelsura® at 2,000 mg.L-1), 4.28 (Anamed + malathion), 4.89 (sugarcane molasses + malathion), 7.19 (sugarcane molasses + spinosad), 7.37 (Flyral® + malathion), 11.03 (Flyral® + Spinosade), 11.24 (Success® 0.02CB), 12.21 (Anamed® + spinosad), 12.36 (Biofruit + spinosad) and 17.15 (Biofruit + malathions. Gelsura® (2,000 mg.L-1) and all formulations containing spinosad provided mortality greater than 80% up to 14 days after application in the absence of rainfall. Both Gelsura® concentrations and Anamed®+ malathion and Anamed® + spinosad showed higher resistance to wash off up to 5mm, while the other formulations were washed, reducing their control efficiency. The insecticides spinetoram, spinosad, alpha-cypermethrin, chlorpyrifos, phosmet and malathion caused mortality of C. capitata adults over 80% both on topical and ingestion. Only chlorfenapyr, spinetoram and chlorpyrifos had significant effects on larvae inside apple fruits with 67, 74 and 84% efficacy. In the field, toxic bait Gelsura®(4.5 L.ha-1 of spray solution) and Success® 0.02CB (4.0 L.ha-1 of spray solution) reduced the number of C. capitata adults captured in the monitoring traps. resulting in average less than 0.22% (Gelsura®) and 1.00% (Success® 0.02CB) of grapes damaged and less than 10% (Gelsura®) and 25% (Success® 0.02CB) of damages on bunches, compaired to the treatment without insecticide (1.68% of berries and 25% of bunches with damage). The determination of a methodology allows to increase the reliability of the results obtained for the toxic baits, and from these studies, it is possible to verify which toxic baits based on alpha-cypermethrin, spinosad and malathion are efficient after aging and at the same time resist to precipitation. Later, it is possible to determine which insecticides are efficient to adults in the form of toxic bait or in cover spray, turning possible to choose the best alternative for field use., The ready-to-use baits Gelsura® and Success® 0.02CB reduce the adult level and the percentage of damages in berries and bunches caused by C. capitata, becoming important tools for the management of the Mediterranean fruit fly in vineyards.