Toxicities and residual effects of toxic baits containing spinosad or malathion to control the adult Anastrepha fraterculus (Diptera: Tephritidae)

An important objective of Integrated Pest Management (IPM) is to reduce chemical contamination of the environment and food; for example by replacing broadcast sprays with selective toxic baits. The objective of the study was to evaluate the toxicity and residual effects of the a ready-for-use commercial bait Success* 0.02 CB®, which contains 0.24 g a.i. L-1 of spinosad, and to compare it’s performance to a few other formulations with spinosad and malathion mixed either in hydrolyzed corn protein (Biofruit® 3%) or in sugarcane molasses (7%) on adults Anastrepha fraterculus (Wiedemann) (Diptera: Tephritidae) in the laboratory, greenhouse and field conditions. In the laboratory, formulations with spinosad caused mortality equivalent to malathion-based toxic baits 96 h after exposure of the insects, regardless of the attractive substance used. In the greenhouse, Success* 0.02 CB®, resulted in mortality of 81.9% of A. fraterculus adults 7 days after application of treatment; being significantly superior to either standard spinosad or malathion treatments (mortality between 44.1 to 62.1%) in the same evaluation period. In field, in the absence of rain, Success* 0.02 CB® and spinosad formulations with Biofruit® 3% or sugarcane molasses (7%) caused mortalities from 70.0 to 83.0% up to 7 DAT, not differing statistically from the malathion treatments (mortality of 100%) during this time. However, at 10 DAT only malathion formulations with Biofruit® 3% or sugarcane molasses (7%) substantial mortalities, i.e., 73.3% and 76.7%, respectively, which were superior to formulations with spinosad (mortality < 45%). However, at 14 DAT all tested formulations caused less than 40% mortality of A. fraterculus adults. One day after a rain (3.8 mm), the formulations with malathion caused mortalities between 56.7 and 81.8%, which were statistically superior to the formulations with spinosad (mortality < 20%). However, after the occurrence of an additional 0.4 mm of rain, all formulations caused mortality lower than 15%. Biofruit® ...