Identification of survival niches of phytopathogens in irrigated agriculture of Guaíra, São Paulo State

Abstract

The identification of survival niches of soil phytopathogens shows a contribution important to the knowledge and performance of agroecossystems. This is fundamental for the establishment of appropriate practices of management and crop rotation. Therefore, a survey was carried out to identify survival niches of phytopathogens in Guaíra, São Paulo State, in soils cropped with irrigated bean and tomato. The results show that from the seeds used for planting, Pseudomonas syringae pv. tomato (tomato) and Xanthomonas campestris pv. phaseoli (Xcph) and Fusarium solani f.sp. phaseoli (bean) were isolated. In crop residues (bean and corn) Sclerotinia sclerotiorum was detected. In soils collected under differents depths, S. sclerotiorum and Sclerotium rolfsii were detected. In spontaneous bean plants, F. solani and Rhizoctonia solani were isolated. Also, weed species were identified as hostess of Fusarium spp. and Alternaria spp.: Senna occidentalis, Amaranthus deflexus and A. hibridus, Bidens pilosa and Digitaria horizontalis, as well as A. deflexus and Emilia sonchifolia for Xcph. The presence of hostess in intercropping will prolongate the survival of pathogens, difficulting the adequated planning of crop rotation.