Control of Citrus Thrips on Lemons, 1996

Eight year old lemon trees in Yuma, AZ were treated with insecticides for control of citrus thrips. The treatments were arranged in a RCB design, consisting of four replicates. Each plot (30 by 90 ft) consisted of three trees 30 ft apart in a row. Applications were made using a backpack air-blast sprayer calibrated to deliver 100 gpa. Treatments were initiated approximately 14 days after petal fall and were applied on Apr 3, Apr 30 and May 15. Evaluations were made on 5 Apr, 9 Apr, 15 Apr, 23 Apr, 29 Apr, 2 May, 6 May, 13 May, 17 May, 20 May and 29 May. Percent infested fruit were estimated by sampling by sampling ten fruit per tree for the presence or absence of immature CT. Fruit damage was assessed on Aug 16 by rating the degree of rind scarring: 1 = no scarring, 2 = slight scarring around the calyx, 3 = significant scarring around the calyx, 4 = slight scarring on the side of the fruit and 5 = major scarring on the side of the fruit. Percentage fruit infested with immature CT were transformed using a square-root transformation for analysis, percentage values are presented in the tables. Differences among treatments were separated using ANOVA and an F protected LSD.