Modelos para a interação da lagarta Anticarsia gemmatalis com o fungo entomopatogênico Metarhizium rileyi

Abstract

In this work we propose a discrete-time model, composed by a system of di erence equations to represent the dynamics of interaction of the velvetbean (Anticarsia gemmatalis) and the entomopathogenic fungus Metarhizium rileyi. Anticarsia gemmatalis is a pest that attacks soybean crop, reducing the leaf area, and consequently causing damage to the production. The fungus M. rileyi is a naturally occurring entomopathogen and provided the weather conditions are appropriate, it acts as a biological control agent of the soybean caterpillar, it can drastically reduce the population density in crops. Through a simple model for the interaction, we note that, depending on the parameters taken, the fungal is able to reduce the susceptible caterpillars density. We veri ed that the susceptible caterpillars density is reduced drastically when inundative applications fungus are made. Finally, supposing that the fungus reproduces faster than the soybean caterpillar scale, we veri ed that the biological control exercised by the fungus causes susceptible caterpillars density to decrease considerably.