STANDARDIZED VISUAL COMPARISON KEYS FOR RAPID ESTIMATIONS OF CITRUS RUST MITE (ACARI, ERIOPHYIDAE) POPULATIONS

Standardized visual comparison keys were effective in improving accura cy and precision in rapid field estimations of citrus rust mite, Phyll ocoptruta oleivora (Ashmead), population densities. A standardized key based on the Horsfall-Barratt system for the measurement of plant dis ease is presented. Errors in mean population estimations were generall y <10% using this key when either leaves or fruits were sampled. Effec tive use of this technique depends on the ability of scouts to adopt a system of grouping instead of counting rust mites. Accurate and preci se population measurements are independent of environmental and geneti c factors; thus this technique is applicable to leaf or fruit tissue i n any geographical location. Use of the modified Horsfall-Barratt syst em for estimating citrus rust mite populations in an integrated crop m anagement program is described.