Distribuição espacial, plano de amostragem e caracterização de injúrias causadas por tripes (Thysanoptera : Thripidae) em videira

Abstract

The thrips are important pests of table grape in the Submédio do Vale São Francisco. This research aimed to study thrips occurrence in three crops systems of grape (certified, semi-conventional, and conventional), the spatial distribution of thrips and the best technique to sample thrips in grape, and to characterize the damage caused by thrips attack on grape fruits. The densities of thrips were evaluated in five areas of Vitis vinifera varieties Sugraone and Brazil, Petrolina, PE. Leaves and flowers were collected, during two subsequent years. The techniques of beating and total remove were compared to survey thrips on flowers. The Taylor power law was used to know the population distribution. To determine injuries and damage to the inflorescence the study was conducted in Casa Nova, BA on the Thompson Seedless grape variety, with infestation levels of 0, 2, 4 and 8 thrips per inflorescence plus the treatment resulting from farm control (12 or more trips). The thrips species found from leaf survey were Heliothrips haemorrhoidalis (Bouché), Retithrips syriacus Mayet, Selenothrips rubrocinctus (Giard), Frankliniella schultzei (Trybom), Frankliniella sp., Scolothrips sp. and nymphs of the Aelothripidae. Thrips found from inflorescences survey were: F. schultzei, Frankliniella brevicaulis Hood, Frankliniella rodeos (Moulton), Frankliniella gardeniae and Frankliniella sp. The Sugraone grape variety conducted in the semi-conventional system produced higher densities of thrips than others systems. There were no correlations between climatic factors with the population of thrips surveyed. In our study, thrips population exhibited contagious distribution and the appropriate sampling technique was beating flower (10 flowers/ha). Sampling thrips on leaves should be performed on leaves located in the middle of the medial branch, and using 10 plants/ha. The equation y = 2.574 + 48.46x (F = 59.98, P = 0.0001, r2 = 0.512) estimated the intensity of injuries in the fruits as function of thrips densities studied. The presence of a whitish halo around a small scar characterizes the damage of thrips on the fruties. The study showed that there is a complex of thrips on the vineyard and the information generated in this research is essential to the success of a sampling plan.