Abstract Insecticides were evaluated spring, 1991 in 2 fields at the University of California’s Lindcove Field Station near Exeter, Calif, for control of citrus thrips. Pesticides were applied with an FMC CP-267 speed-sprayer pulled behind a tractor. In Field 23, 4 methods of application were compared with Baythroid: the same amount of active ingredient on a per acre basis was applied in 50, 100, or 200 gal of water per acre (gpa) using outside coverage (achieved by reducing fan speed from a full throttle wind velocity of 130 mph to 80 mph) and a driving speed of 2 miles per hour (mph); in the fourth treatment, the same machine settings were used as with the 200 gpa application but driving speed was increased to 4 mph resulting in an application of 100 gpa. In Field 41-42, 5 treatments were compared, all with outside coverage applied at 2 mph: split applications of 10 fl oz of Agri-Mek per acre in 50, 100, or 200 gpa or 20 fl oz in 100 gpa were compared against a single post petal-fall application of Carzol. Each field was divided into 2 blocks and one replicate of each treatment was assigned to each block randomly; each replicate plot was 6 rows wide and 5-8 trees long. In each plot, 6 data trees were chosen from the center 2 rows of each plot, excluding the trees at the end of a row. Ten outside fruit per data tree from the inside of the 2 data rows from knee to eye level were sampled for citrus thrips infestation at 4 times during the critical period (the first 6 wks after petal-fall) during which citrus thrips fruit scarring occurs. Citrus thrips fruit scarring evaluations were taken in Aug 1991 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 (approximately 10% severe scarring of outside fruit as sampled in this study). In 1991, late Apr and May were relatively warm—daily maximums were between 64 and 95°F (mean 79.0°) in the 4 wks after petal-fall. A little precipitation occurred (0.04 inch, 8 May; 0.08, 17 May; 0.04, 24 May; none in Jun) but probably had little effect on the treatments. These groves had low levels of predaceous mites.