Citrus Thrips Control Trial in California, 1986

Pesticides were evaluated for control of citrus thrips populations in Field 12 (16 year old Atwood navel oranges) of the Lindcove Field Station near Exeter, CA. The entire plot was treated 3 Apr for citrus red mite and fruittree leafroller with Morestan 25%WP, 5 lb/acre plus Dylox 80%SP, 2.5 lb/acre. Treatments for citrus thrips control 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 (21 Apr). Four-tree plots were used with 3-7 (normally 3) replications. Posttreatment counts were taken weekly on most of the plots on 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 week critical period following petal fall. Citrus thrips fruit scarring counts were taken 1 month prior to harvest (on 13-14 Oct) 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.