Citrus Rust Mite Control with Avermectin B1, 1981

Abstract

Abstract Avermectin, citrus oil spray (Sunspray 6N), and avermectin with citrus oil were compared to Vendex for efficacy against the citrus rust mite (CRM). Treatments were completely randomized and replicated on 4 single-tree plots of Ruby Red grapefruit on 30 ft x 25 ft spacing. All treatments were applied initially on May 29 with a John Bean Model 1010-MTBYT sprayer hand-gun at 225 psi, ca 10 gal/tree. Treatments were not reapplied until residual control of CRM was lost. At each count date, 25 fruit/replicate were randomly selected and CRM counted in a 1 cm2 lens field at 10X on the top, medium and bottom of each fruit. CRM counts were terminated after Sep 2 due to extensive fruit russet and low CRM populations in the untreated control. Fifty fruit/replicate were randomly selected and evaluated for CRM damage. Damage was expressed as percent russet, i.e. fruit with moderate to severe damage (US#2 fresh or process fruit).