ABSTRACT
One of the indirect actions of weeds in interfering in cultivated species is their potential to host causative agents of diseases. The root-lesion nematode (Pratylenchus brachyurus) has caused a series of damages to several crops in Brazil. For the management of this plant parasite, cultivation of different Crotalaria species has been used. The aim of this study was to evaluate the host status of weeds to P. brachyurus, as well as the suppressive effect of different Crotalaria species. An experiment was installed under greenhouse conditions in completely randomized design, in factorial arrangement (2x17), with six replicates. The first factor consisted in the presence or absence of nematode inoculation. The second one corresponded to seventeen plant species, of which eleven were weeds, four were Crotalaria species (C. breviflora, C. juncea, C. ochroleuca and C. spectabilis), and two were soybean varieties, which were used as control and were hosts of P. brachyurus. Inoculation of the root-lesion nematode did not influence the plant height and the aboveground dry mass of the different evaluated species. Portulaca oleracea, Amaranthus viridis and Sida rhombifolia consisted in the species with larger number of nematodes per root system, and only S. rhombifolia showed behavior similar to that of the control (soybean variety BMX Potência RR®). In relation to the number of nematodes per gram of root, the higher values were observed for A. viridis, followed by P. oleracea. Excluding C. juncea, all the remaining Crotalaria species showed to be good options for the management in areas infested by P. brachyurus.
Keywords
Indirect weed interference; phytonematodes; root-lesion nematode