Applying different infective structures of Beauveria bassiana to Coffea arabica infested with Hypothenemus hampei (Coleoptera: Curculionidae) under field

Abstract

Coffee is the most appreciated beverage in worldwide; Brazil is the largest producer and exporter of this commodity. Organochlorine endosulfan was banned from the country in 2013 due to its teratogenic agent-related features. Since then, coffee plantations have experienced increased Hypothenemus hampei infestation rates. The aim of the current study is to assess variations in the rates of Coffea arabica fruits brocaded by H. hampei after the application of entomopathogenic fungal species Beauveria bassiana IBCB66. Experiments were carried out with ‘Catuaí’ and ‘Mundo Novo’ cultivars between 2018 and 2020, during the borer transit period. Three experiments were carried out based on the application of the aforementioned fungal species on the investigated coffee plant species, both by spraying and sprinkling, at 30-day intervals; 10 fruits were collected per face of each useful plant in each repetition. The experiment has followed a randomized blocks design with five treatments, including the control, and five repetitions, each. Beauveria bassiana Ecobass (IBCB66) wettable powder spray, at the concentration of 2 × 1013·ha–1, was used in experiments I and II. On the other hand, the mix used in experiment III was prepared with blastospores at concentration of 5 × 1012·ha–1 blastospores + 0.1% Silwet. The sprinkling process in all three experiments has used dry aerial conidia at concentration of 2 × 1013·ha–1. Collected data were subjected to analysis of variance (ANOVA), which was followed by Fisher’s test at 5% probability level, in the SISVAR software. More than 35,000 fruits were assessed. In addition to variations between experiments, results have evidenced that the rate of brocaded fruits remained high.