Epidemiologia e manejo do mofo cinzento no morango

Abstract

Strawberry is a highly perishable product with a reduced post-harvest shelf life, due to, among other factors, a high respiratory rate and incidence of rot affecting fruit. Botrytis cinerea, which causes gray mold, is considered one of the most important fungi in Brazil, and can cause losses of 80 to 90% from production to commercialization. Aiming to reduce economic damages, significant losses and increase the shelf life of the strawberries in the post-harvest, studies of alternative fungicide control methods, and climatic conditions favoring the disease, should be made for proper management. The present study aimed to evaluate the pathogenicity and aggressiveness of B. cinerea isolates (BC1, BC2, BC3, BC4 e BC5) from different hosts in strawberry; through the more aggressive isolate, evaluate the influence of ideal inoculum concentration (103, 104, 105, 106, e 107 conídios.mL-1), temperature (15, 18, 20, 25 e 28ºC) and the wetness period (0, 12, 24, 36 e 48h) for the establishment of the disease; evaluate the effect of calcium chloride, potassium chloride and calcium carbonate by immersing the fruits in the solutions in different concentrations (0,3%; 0,6% e 1%), on the severity of gray mold in strawberry, as well as, verify the influence of these products on physical-chemical attributes such as pH, total soluble solids (SST), titratable acidity (AT) and firmness. All isolates showed up pathogenic, being used BC5 the following steps. Regarding the epidemiological aspects, it was verified that the highest concentration of inoculum (107 conidia.mL-1), wetting period of 48 h and temperature of 28 °C, presented the largest lesion sizes. The calcium chloride (CaCl2) and potassium chloride (KCl) applications were able to reduce the severity of the disease in all applied concentrations. It was observed that the treatments with calcium carbonate (CaCO3) were not effective in reducing the diameter of the gray mold lesion in strawberries, since there was no significant difference between treatments. No significant changes were observed in the pH, SST, AT and firmness factors indicating a loss in product quality.