Induction of resistance has been identified as a sustainable alternative for disease management, but little information is known about the interference of such products in the postharvest fruit. Thus, the present study aims to evaluate the production and ripening of grapes 'Isabel' (Vitis labrusca) from plants treated with resistance elicitors in Natuba-PB, Brazil. The experiments were carried in two seasons, between September 2009 and January 2010 (season 1) and February to June 2010 (season 2). It was used eight treatments (Control; Fungicide (Metiram + Pyraclostrobin); Potassium phosphite; Agro-Mos®, Fungicide + Potassium phosphite; Fungicide + Agro-Mos®, Potassium phosphite + Agro-Mos® and Fungicide + Potassium phosphite + Agro-Mos®) with four replications of five plants. The pulverizations were made every 10 days, beginning 20 days after pruning in total of 12 applications. The collected fruits were held at 45, 60, 90 and 120 days after pruning. The variables evaluated were: bunch weight, length and diameter of the clusters, and pulp yield, soluble solids (SS), pH, total acidity (TA) and SS/TA ratio. The treatment with Potassium phosphite promoted a 24% increase on bunches length, compared to control at season 1. The pulp yield and harvest index were not affected by treatments and soluble solids content was positively influenced by the application of potassium phosphite, with increases exceeding 60% in both seasons.
Plasmopara viticola; resistance induction; production; maturation
