Evaluation of Bacillus thuringiensis and Amblyseius swirskii for the control of thrips (Chaetanaphothrips signipennis) on Cavendish banana (Musa AAA) fruit

Resumen

Banana is one of the primary fruit crops in Ecuador, responsible for the generation of a significant proportion of the country's foreign exchange. Consequently, the fruits must adhere to exacting quality standards in order to satisfy the demands of international marketing. One of the most significant challenges currently facing banana production is the considerable damage caused by infestations of Chaetanaphothrips signipennis (Thysanoptera: Thripidae). The damage observed ranged from 35% to 60% of the banana bunches, highlighting the necessity for the development of control alternatives. The impact of two biological control agents, namely the bacterium Bacillus thuringiensis and the predatory mite Amblyseius swirskii, was assessed in the context of thrips management on Cavendish banana (Musa AAA). The experiment employed a completely randomized design, comprising nine treatments, two controls and three replications per treatment. The variables subjected to evaluation included the number of thrips at three application periods (weeks 34, 35, and 36 of the annual calendar), the severity of damage (assessed on a scale), and yield in boxes and kilograms per hectare. Furthermore, an economic analysis of the treatments was conducted. The presence of thrips at weeks 34, 35, and 36 ranged from one to three insects under different doses of B. thuringiensis (2, 3, and 5 ml/L water). The results demonstrated a notable decline in the number of thrips. Nevertheless, the extent of damage remained at level 2 on the severity scale, corresponding to 10% damage. The highest benefit-to-cost ratio was observed in T6, with a value of 1.08.