Toxicities and Residual Effects of Toxic Baits Containing Spinosad or Malathion to Control the AdultAnastrepha fraterculus(Diptera: Tephritidae)

Abstract

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® 3% can be used as a replacement for sugarcane molasses (7%) in formulating toxic baits and Success* 0.02 CB® and other formulations with spinosad may be used to replace malathion to manage populations of A. fraterculus. In practical field operations, the effectiveness of toxic bait formulations may be extended by applying them to the lower canopy where they are partially protected from rain.