BIOLOGICAL EFFICACY AND SELECTIVITY OF ACARICIDES IN PAPAYA (Carica papaya L.)

Abstract

Mites are considered the second pest in importance in papaya (Carica papaya L.) in Veracruz, Mexico, caused by a general increment in pesticide use that might unbalance predatory populations. Efficacy of acaricides was evaluated against phytophagous mites, and their selectivity to predators in papaya cv. Maradol. A completely randomized block design with nine treatments and four replications was used. Significant differences (P = 0.005) were found in the number of phytophagous mites alive per leaf after the third weekly application. The lowest populations of pest mites per leaf (2.6, 3.9, 3.5 and 4.9) were observed in the following treatments: dicofol rotated with bifenthrin, paraffinic oil alone, sulphur powder alone and a weekly regime of fatty acid salts followed by paraffinic oil and azadirachtin 1.2%. Azadirachtin 1.2% alone had a lower efficacy than the previous group (5.8 mites per leaf), and the following pesticides were not significantly different (P > 0.05) than the control (17.4 mites per leaf): fatty acids sprayed alone (6.7), azadirachtin 4.5% alone (9.5) and drenched imidacloprid (7.6). No differences were found among treatments in the number of predatory mites, possibly due to the low mite densities found.