Control decision‐making systems for Anacampsis phytomiella in cashew orchards as a function of insecticide spray method and irrigation use

Abstract

Cashew (Anacardium occidentale) is one of the main tropical fruit trees, and its chestnuts are the most consumed in the world. Cashew orchards are managed under irrigated and unirrigated conditions, and pesticides are applied manually (hand sprayer) or by a tractor‐powered sprayer. The chestnut moth Anacampsis phytomiella (Lepidoptera: Gelechiidae) is the primary pest that attacks cashew chestnuts, causing losses of up to 53% in yield in the orchards. Sampling plans and economic injury levels (EILs) are part of the decision‐making systems of integrated pest management (IPM) programmes. The EIL varies according to the method of insecticide spraying (hand sprayer or tractor) and in irrigated and unirrigated cashew orchards. This study aimed to determine the EIL and a sequential sampling plan for A. phytomiella in cashew orchards. Decision‐making systems were determined using data collected from 44 orchards over 3 years. EILs ranged from 0.53 to 1.53 for chestnuts attacked by the pest in bunches with 10 chestnuts, depending on irrigation and insecticide spray methods. The sequential sampling plan was validated using field‐collected data (providing correct decisions in 100% of the fields and an average time saving of 83.65%), operational characteristic (OC) and average sample number curves. In conclusion, determined decision‐making systems can be incorporated into IPM programmes for A. phytomiella in cashew orchards, as they enable correct, rapid and cost‐effective pest control decisions.