Ocorrência de fungos fitopatógenos associados ao declínio de ramas de cucurbitáceas, em Caatinga.

Abstract

The Caatinga biome is rich in biodiversity. Many plant species are hosts of pathogens that cause diseases on crops and in many cases even death of plants and eradication of crops. Melon (Cucumis melo) and watermelon (Citrullus lanatus) are economically important crops in Brazilian Northeast. However the occurrence of pathogens causing root decline of foliages in cucurbits results in losses to these crops. This disease is associated with fungus Monosporascus cannonballus which is considered the causal agent, it has recently been detected in Caatinga’s soils no cultivated. With the hypothesis that Caatinga’s native plants are alternative hosts of this fungus, the objective of this study was to conduct a research Caatinga’s native plants as possible alternative hosts of this fungus. The experiment was conducted from 06/2013 to 02/2014 with the prospect of the plants in Rio Grande do Norte and Paraíba states later these plants were taken to the laboratories of plant pathology at Federal Rural University of Semi-Arid and Science Center and Agrifood technology - Pombal where the scientific identification and analysis of their roots to detect the occurrence of fungi was carried out. Then took place the isolation of pathogens from the roots of all species collected in a total of 500 plants in ten areas into two states. Immediately after the incubation period the identification of the pathogenic fungi was performed. In none of the species of plants native to the Caatinga was detected the presence of the fungus M. cannonballus, however it was found that of the 22 species studied, 18 are host to pathogens causing disease in cucurbits. Macrophomina phaseolina and Rhizoctonia solani were the fungi found. In none of the five areas belonging to the state of Rio Grande do Norte was found Rhizoctonia solani in the roots of the species.