ISHS Acta Horticulturae 199: II International Workshop on Temperate Zone Fruits in the Tropics and Subtropics
PESTICIDE REDUCTION BY MEANS OF APPLE SCAB WARNING SYSTEM AND PEST MONITORING IN APPLE ORCHARDS OF SANTA CATARINA - SOUTH BRAZIL |
| Authors: | R. Melzer, O. Berton, A. Orth |
| Abstract:
In three years of preliminary studies Mills' predictive system was tested for apple scab control in Santa Catarina, Southern Brazil, in order to introduce a warning system for small apple growing farmers. Using thermohygrographs combined with leaf wetness recorders, microclimatic conditions at four different locations within a radius of 40 km were evaluated and ascospore liberation was observed, showing no marked differences. Trials carried out at the Research Station of Caçador revealed a significant reduction of fungicide sprays on the bases of Mills' table in comparison with the recommended preventive treatments, giving good control of Venturia inaequalis, Glomerella cingulata, Leptothyrium pomi and Gloeodes pomigena. Monitoring of the South American fruit fly (Anastrepha fraterculus (Wied.)) with 4–5 bait-glasses/ha of the Valencian type, filled with 25% vinegar and evaluated two times per week, proved to be effective for the observation of population dynamics and to determine the threshold level of this pest. Insecticides were sprayed when 0.5 to 1.0 fruit fly were captured per day per bait glass. Best control was obtained with Fenthion (0.05% a.i./100 1) in cover sprays. Monitoring of the oriental fruit moth (Grapholita molesta) was carried out using 2 pheromone traps/ha. First insecticide sprays are recommended when 15 male moths are trapped per week. | |
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