Citrus Thrips Control Trials in California, 1985

Abstract

Abstract Materials were tested for control of citrus thrips populations in Field 12 (15 year old Atwood navel oranges) of the Lindcove Field Station near Exeter, CA. Treatments were applied using a hand-gun at 500 psi, outside coverage and approximately 200 gpa (except Kelthane thorough coverage, 1000 gpa) on various dates pre and post petal fall (1 May). Four-tree plots were used with 2-12 (normally 3) replications. Posttreatment counts were taken weekly on some of the plots of the percent of fruit on the exterior of the tree from knee to eye level (10 fruit per tree) that were infested with citrus thrips during the 6 wk critical period following petal fall. Citrus thrips fruit scarring counts were taken 1 mo prior to harvest on all fruit on the exterior of the tree from knee to eye level. Scars were rated as slight (any citrus thrips scarring) or severe (complete ring scar or extensive surface scarring, equivalent to level causing fruit downgrading in a normal year). Economic scarring levels are approximately 5% severe scars.