Decision‐making for thrips control in soybean fields using precision agriculture principles

Abstract

AbstractIn precision agriculture, sub‐areas of fields with similar features are called management zones and the inputs applied similarly in these zones. Such notion of management zones is applicable to high‐output soybean fields where thrips are an emerging problem leading to losses up to 15%. Management zones are an agricultural management strategy that can be used for decision‐making for controlling thrips on soybean fields. Thus, a 2‐year study was carried out on commercial soybean fields aimed at developing a decision‐making system for controlling soybean thrips using management zones. Three control programmes were established and assessed: Cl‐conventional control with insecticide use in the entire field; IPM‐CS‐conventional sampling plan + spray upon reaching the economic injury level (EIL; 3.43 thrips/sample); and IPM‐MZ‐spraying only specific areas of the field where thrips density reached the EIL. The decision to control reached using the IPM‐CS and IPM‐MZ programmes was 3× lower than those of the CI, which incurred in 75% mode decision mistakes. Furthermore, the decision to spray insecticides based on analysis of data for Cl was also incorrect. In 8.5% (3.6% of treated and 4.9% of non‐treated) of the field, the decisions of the IPM‐CS programme were incorrect. The total cost of the Cl programme (US$ 11.4/ha) was higher than that of the IPM‐CS and IPM‐MZ programmes (US$ 3.2 ha−1). Therefore, owing to its technical, economic, and environmental advantages, the establishment of management zones seems worthy of incorporation in integrated thrips management decision‐making systems for soybean fields.