Diversidade genética de Fusarium spp. e Manejo Alternativo da Fusariose do abacaxizeiro

Abstract

Whereas the proper management of plant diseases requires the correct characterization and identification of agent (s) etiological (s), in view of the high heterogeneity by species of the same genus. As well as the management of diseases in agriculture with the use of chemicals to control it has been used conventionally, considered economically viable for many, however, is also causing concern have been the overuse offers several health risks human and sustainable environmental balance. The objective of this research was to identify the genetic diversity of Fusarium spp. populations in states of Paraíba state, Pernambuco (PE) and Rio Grande do Norte (RN), Brazil and, evaluate plant extracts as an alternative to control Fusarium wilt of pineapple. It was collected fruit of pineapple, cv. Perola with signs and symptoms of Fusarium in producing areas in PB, PE and RN. The isolates were characterized morphologically and molecular characterization was performed using gene sequences of the second largest ribosomal subunit - RPB2. Plant extracts of Caesalpinia ferrea (CF), Anadenanthera colubrina (AC), Momordica charantia (MC) were used at concentrations of 500, 1000, 1500 and 2000 ppm; while the resistance inducer acibenzolar-S-methyl (ASM) was used at 2.0 g / ha. As a standard of comparison, it was used the fungicide tebuconazole (75 ml / h) and sterile distilled water (control). The assessment of the severity of the disease was performed using a i and the disease index to determine the area under disease progress curve (AUDPC). Post-harvest assessments were conducted in ripe fruits through the pH, total soluble solids, titratable acidity, firmness and activity of peroxidase (POX), polyphenol oxidase (PPO) and phenylalanine ammonia-lyase (PAL). It was found that the isolates associated with pineapple fruits showed high and wide variability determined by phenotypic and molecular markers analyzed. There are at least two species of Fusarium, and F. guttiforme, associated with Fusarium in fruit pineapple among isolates collected; pathogens of this study showed symptoms, signs and different levels of pathogenicity in fruits of pineapple. The herbal extract of M. charantia presented with potential in reducing the severity of fusarium disease in fruits of pineapple 'Perola' through the fungitoxic mechanism of action; M. charantia extract at higher concentrations positively affected the physical and chemical characteristics of the fruits.