ESTRATÉGIAS DE MANEJO DA SEPTORIOSE EM TOMATE DE MESA VISANDO BAIXO RISCO DE CONTAMINAÇÃO COM AGROTÓXICOS

Abstract

A study was developed with the objective of evaluating strategies for the application of phytosanitary products for the control of tomato septoriosis with low risk of fruit contamination by pesticides. The study was conducted in the experimental area of the Instituto Federal Goiano - Campus Morrinhos, in 2019. Two field trials were conducted with the same experiment in order to verify the repeatability of the results. The plants were tutored with phytos, and frequently the sprouting and conduction of two stems was performed. After the sixth bunch, the apical meristem was pruned. In both, 9 treatments were evaluated: 1) untreated control, 2) weekly application of chemical fungicides (calendar), 3) weekly application of chemical fungicides with change to biological fungicides at the beginning of harvest (calendar + biological), 4) application of chemical fungicides based on prediction system (forecast system), 5) application of chemical fungicides based on a prediction system with change to biological fungicides at the beginning of harvest (biological + prediction system), 6) application of biological fungicide at the recommended dose (biological), 7) application of biological fungicide with twice the recommended dose (biologicalX2), 8) weekly application of copper hydroxide (copper), 9) weekly application of copper hydroxide with change to biological fungicides at the beginning of harvest (copper + biological). The experimental design was in randomized blocks (DBC), with four replications for each treatment. The plot consisted of a 5 m long flowerbed containing 14 plants. Among the blocks, corn was sowed to serve as a physical barrier between treatments and prevent drift of applications. The severity of septoriosis was evaluated as a function of natural infection. As the fruits reached the harvest point (colored fruits), the harvest was carried out and at the end the total productivity and per class were estimated. The data were submitted to variance analysis and when the effect of the treatments was observed (P<0.05), the means were compared by the Tukey test at the level of 5% probability. In view of the results of the present study, it was observed better efficiency of the weekly application of chemical fungicides, compared to the application based on the prediction system and the use of biological product. However, copper hydroxide showed satisfactory results compared to other site-specific fungicide or protective actives, whose toxicological classification was worse. Therefore, it can be used to control the disease at the time of harvest.