Economic threshold decision rules as an integrated pest management tool in Florida citrus production

The decision to pursue management action against an economic pest is a keystone decision in any integrated pest management program. For any particular pest, farm-level decision rules have been developed to judge when management action is economically justified. These economic threshold decision rules have been adopted by producers with varying degrees of practicable success. Both qualitative and quantitative threshold decision rules have been developed and applied. While model rigor and performance are important considerations, a producer will also consider implementation costs when deciding to adopt any decision rule framework. Through investigation of the plant-host relationship between citrus and the Citrus Rust Mite (Phyllocoptruta oleivora Ashmead), our study examined the benefits and costs associated with different decision rules from the perspective of the producer. Prescription-based decision rules in managing Citrus Rust Mite are justified in typical mite growth situations that occur at predictable times. Comparison of an action threshold with a binary decision tree demonstrated that treatment timing can have both positive and negative profit implications. These differences are largely a function of how and when the pest population increases. Simpler threshold decision rules will likely perform comparably with the more complex models if the residual control of pesticides is high. The additional scout and information costs associated with more-complex decision rules become warranted when uncertainties exist regarding the target market outlet (i.e., fresh versus processed fruit markets) and in cases where mite populations are exceptional with respect to intensity, timing, and/or pace.