Condições favoráveis para ocorrência da podridão por lasiodiplodia e métodos alternativos de controle na pós- colheita do maracujá amarelo

Abstract

Phytopathogenic fungi are responsible for significant losses in yellow passion fruit in the postharvest, among these the Lasiodiplodia theobromae that damages the fruit thus impairing its commercialization. The objectives for the development of this research were to evaluate the epidemiological parameters of lasiodiplodia rot in yellow passion fruit and the effect of plant extracts, inducing resistance and solid formulations of phosphite in controlling this disease. In the first article, beyond the study of the epidemiological parameters of inoculum concentration (102, 103, 104, 105, 106 and 107 conídia.mL-1), wetness (0, 12, 24, 36, 48 h) and temperature (20, 25, 30, 35 ° C) of three isolates of L. theobromae, enzymatic characterization was performed in 43 isolated solid substrates, where it was possible to detect halos of degradation showing the ability of this fungus has to produce hydrolytic enzymes amylase, cellulase, lipase and protease. In relation to epidemiological aspects, it was observed that the optimal conditions for the establishment of the disease consisted of high inoculum concentrations (106 and 107 conídia.mL-1), temperature around 30 ° C, and wetness period of 48 hours. In the second article evaluated the effect of alternative products to control the disease. For this, the fruits were treated with extracts of melon mentrasto, ginger, basil, cinnamon, yellow passion fruit peel, and potassium phosphite, calcium phosphite, and Ecolife Agro-Mos® in five concentrations. The fruits were treated by immersion in suspensions of the products for 10 minutes. Three hours after treatment, the fruits were inoculated with a suspension at a concentration of 106 conídios.mL-1. Despite all the products tested show fungitoxic properties, better results were obtained with potassium phosphite, Ecolife ® and melon mentrasto extract. The best doses obtained were tested in combination and found that calcium phosphite (5 mL) + extract of yellow passion fruit peel (80%), calcium phosphite (5 mL) + melon mentrasto extract (60% ) and Agro-Mos (300μl) + basil extract (80%) promoted smaller sizes of lesions. In the third article we evaluated the efficiency of different formulations of solid nature of phosphites in reducing decay. K, K+BMo, Ca, Ca+B, Cu, Zn, Mg e ultra ABS nas concentrações de 1, 2, 3, 4 e 5 g.L-1. Treatment and inoculation of fruits were carried out following the same methodology as the previous article. The results showed that solid formulations of potassium phosphite, FK+FBMo, FCa, FCa+FB, FZn e FMg demonstrated fungitoxic properties inhibiting the development of lesions. Physical-chemical properties of fruit showed that the treatments promoted changes to the content promoted ATT, SST and pH.