Optimizing pest management for coffee berry borer: An application of optimal control theory

Abstract

Coffee berry borers (CBB) have been affecting coffee crops in Puerto Rico since at least 2007. In general it is a difficult pest to control as it spends most of its lifetime inside the coffee berry, making control methods such as traps and pesticides less effective. Applying these control methods in Puerto Rico is particularly challenging as both locations have high wages, which makes hiring the necessary labor inaccessible for smaller farms, and they have stricter laws regulating the use of pesticides.<br /> <br /> Based on these circumstances, we designed an optimal control problem that would maximize profit by maximizing the revenue from the yield of coffee and minimizing the cumulative cost of the control through variations of the control curve. This provides an optimal distribution of control effort over time. Our simulated results were then compared to results found through field experiments.<br /> <br /> We found that most of the control effort should be focused at the beginning of the season, when CBB have not yet entered the berry, and are still susceptible to traps and pesticides. This effort quickly decreases as the season progresses. This confirms field results that have found that a higher rate of sprays concentrated at the beginning of the season is more effective than calendar based sprays spread out uniformly over the season.