1 CONTROL OF HARMFUL THYSANOPTERA ON HASS AVOCADO CROP

Since thysanoptera affect commercial quality of Hass avocado, the search for appropriate alternatives to control them was initiated. Main objectives were: 1. Prove efficiency of different concentrations of mineral oil to control thrips. 2. Determine opportunity of treatment based upon abundance curve of these insects. Tests were performed during 2006/07 at La Ollada, Palma Sola, Jujuy, on 4-year-old plants, established on 6 x 8 m spacing and contour rows. Treatments were mineral oil at 1, 1.5 and 2 % (T1, T2 and T3), Endosulfan 50 at 1.75 % (T4) and one control. A Jacto 2000 sprayer with high volume and nozzle was used, with a completely randomized block design with 4 replicates of each treatment: Number of live thrips and percentage of healthy fruits were evaluated, along with light, medium and severe damages from a total of 50/treatments. The data were subjected to ANOVA, while the efficiency was determined through Abbott formula. Periodical monitoring was based upon random sampling of 2 fruits/plant and 8 per each treatment. Two spray applications were performed, being T4 the most effective (41 %) at first, followed by T3 (17%). During the second spray application, no treatment was different from the control. The highest percentage of healthy fruits with light injury was due to T4 (76 %), followed by T3 and T1 (58 % for both). Regarding severe injuries T4 and T3 had the lowest levels (1 and 2 %, respectively), whilst maximum damage corresponded to the control (46%)