Sun vs. shade affects infestation, total population and sex ratio of the coffee berry borer (Hypothenemus hampei) in Puerto Rico

Abstract

Sun and shade coffee (Coffea arabica L.) provide different biotic and abiotic environments which can affect the damage, distribution and reproduction of coffee pests. However, the effect of shade on damage by the coffee berry borer (CBB) Hypothenemus hampei (Ferrari), the most important coffee pest worldwide, is controversial and unclear. We compared infestation, total population per fruit and sex ratio of the CBB between shade and sun coffee, during two coffee-growing seasons in Adjuntas, Puerto Rico. According to generalized linear mixed models, CBB infestation was significantly higher in shade plots, and ranged from 7–52% compared with 4–26% in sun. However, the total population per fruit was higher in sun coffee fruits than in shade coffee, and the sex ratio was more biased to females in sun coffee. Sun coffee was characterized by higher temperatures and lower relative humidity. Environmental variables appeared to be important drivers of CBB population densities in field, with positive correlations between temperature and the number of pupae, juveniles, females and males. This tendency of larger populations in sun plots could represent a serious threat for coffee. In addition to fewer CBB in infested fruits in shade plots, we observed that shade coffee also had more natural enemies of CBB such as ants and entomopathogenic fungi.