California Citrus Thrips Small Plot Trial, 1995

Abstract

Abstract Insecticides were evaluated spring, 1995 in Field 12 (25 yr-old Atwood navel oranges) at the University of California’s Lindcove Field Station near Exeter, California for control of citrus thrips. Pesticides were applied with a Bean hand-sprayer at 500 psi, outside coverage, approximately 200 gpa. Field 12 was divided into 4 blocks of 92-96 trees (23-24 replicates) and 22 treatments were applied with one replicate of each treatment assigned randomly to each block except extra replicates were assigned to the untreated control; each replicate was four contiguous trees. Citrus thrips fruit scarring evaluations were taken in Oct, 1995 on all fruit on the exterior of data trees from knee to eye level. Typical scarring levels on outside fruit as sampled in this study are approximately twice as high as percent scarring of fruit sampled from the entire tree (inside fruit are less severely scarred). Scarring was rated as: (a) none, (b) slight (any citrus thrips scarring), or (c) severe (complete ring scar or extensive surface scarring at a level that would cause downgrading of fruit in a commercial operation). Economic scarring levels in a normal year are approximately 5% severe scars.