Evaluating trap cropping strategies for insect pest control through simulation models

Trap cropping is a habitat management strategy where the aim is to reduce damage to the crop of interest by mixing it with other plants that are highly attractive to insect pests. However, despite its potential, the application of this strategy has been limited mainly due to a lack of consistent effectiveness. Here, we developed an individual-based spatially explicit model that accounts for reproduction, movement and mortality of insects within a mixed crop system. This model was used to evaluate the effects of varying trap crop spatial configurations (border, stripes and patches), cover (2, 4 and 10 %) and supplemental management strategies (early harvest and pesticide application) to gain insight into the best control options offered by trap cropping. As a case study, we considered Liriomyza huidobrensis, a world known leafminer pest. Our results showed a maximum reduction of about 34 % in the pest population of the main crop when using trap plants. The supplemental management strategy had a stronger effect than other factors, with pesticide use being the best option. A sensitivity analysis showed that demographic parameters were more relevant than the behavioral ones in determining the success of the method. Our model suggests that trap cropping is only suitable for controlling L. huidobrensis if a pesticide application is added to the trap crop. Individual-based models, which are cheaper and less laborious than direct field testing, might provide an important tool to help define management schemes for the control of herbivorous pests.