Effect of antagonist fungi and chemical products in the control of brown rot in peach orchards.

Abstract

An experiment with biological control in the field was conducted in the county of Lapa-PR, for the control of Monilinia fructicola in peach cultivar BR-1. Biological agents previously selected from the production field were compared with the fungicide iprodione and with Ca and K phosphites. The experiment consisted of 10 treatments, being six antagonist fungi (F1, F2 and F4 - Trichothecium roseum; F9 Penicillium sp; F3 Cephalosporium sp; F13 Alternaria sp), two phosphites (Ca and K), iprodione and check. The evaluation was carried out per field incidence and postharvest and the treatments were applied by means of pulverization and immersion, respectively. In relation to the field incidence, the following could be pointed out: iprodione, and in sequence, K phosphites with 71,4 and Ca phosphites with 64,2% control, and among the antagonist fungi F3, F1 and F2 with control level superior to 64% in relation to the check. After harvest, the fruits were kept at room temperature and evaluated on the third day of exposure by disease incidence. At this moment low efficiency among the treatments was observed, exception only to the fungicide. The following were also evaluated: the average weight of the fruits, diameter, pulp firmness and total soluble solids, and no statistical difference between the treatments was observed. Parallel to the field evaluation, the non-pulverized fruits were harvested to receive, in postharvest, the same treatments carried out in the field. They were damaged, immersed into the treatments and evaluated according to the incidence of disease on the second and fourth exposure days in the environment. Iprodione, Ca phosphite and F1 exerted higher control of the latent infections. In the damaged areas, the action of iprodione and F2 and F4 were most noticeable.