Treatment of pineapple guava (Acca sellowiana) seeds: effect on germination and fungal incidence

Abstract

The aims of this study were to evaluate the efficiency of chemical and biological fungicides on the control of fungi (Colletotrichum gloeosporioides (Penz.) Sacc.) associated with seeds of the pineapple guava and their effects on seed germination. We used fungicides captan, carbendazim, carbendazim + thiram, carboxim + tiram and the commercial product Trichodermax (in a concentration of 1.5 x 109 viable spores of Trichoderma asperellum per ml of product) at the recommended doses for large crops. We used seeds obtained at Concordia and São Joaquim cities, both from Santa Catarina state, Brazil. The seeds were tested for sanity in V8 agar culture medium, and for germination using filter paper as substrate. The fungi found in the untreated plants were: Alternaria sp., Aspergillus flavus, Aspergillus niger, Penicillium sp., C. gloeosporioides, Fusarium spp. and Phomopsis sp. The chemical treatments and the Trichoderma asperellum-based biological one reduce the incidence of fungi in seeds of the pineapple guava. However, the former negatively influence seed germination. Evaluating the effects of several doses and products is necessary not only to control the incidence of seed-associated fungi, but also to decrease the percentage of abnormal seedlings and dead seeds that probably result from phytotoxicity of the products used, in order to ensure the production of healthy and vigorous seedlings in plant nurseries.