Determinação da eficáncia de diferentes espécies de crotalária no controlo de nemátodos da galha (meloidogyne spp.)

Abstract

In Mozambique, the root-knot nematode (Meloidogyne spp.) is considered the most important nematode in crops, especially in nightshades, legumes and cucurbits, hence work has been carried out to identify rotational crops or varieties resistant to this pest. Eight species of Crotalaría, namely: C. Juncea, C. Spectabilis, C. Capensis, C. Intermedia, C. Lanceolata, C. Pallida, C. Ochroleuca, C14 were tested and compared with a tomato variety (UC-82B) , a variety susceptible to the root-knot nematode. The tests were carried out in two stages and in different places and consisted of: Greenhouse trial, in which the plants were inoculated with about 5000 nematodes per pot, carried out between January and November 1993, in the greenhouses of the Vegetal Quarantine, in Maputo. The effectiveness of Crotalaria species in reducing the root-knot nematode was evaluated based on the degree of infestation (galle index), using a scale of 0-10, and the number of eggs and larvae in the roots. This evaluation was carried out sixty days after inoculation (in the greenhouse). This trial allowed the selection of C. Juncea, C. Spectabilis and C. Capensis, which were subsequently tested in a field highly infested by Meloidogyne species between March and June 1994, in the Faculdade de Agronomia experimental field (University field). Three months after the crotalarias transplantation, the roots were evaluated and the tomato was immediately transplanted in the Crotalarias plots and in the fallow area. Tomatoes were also evaluated three months after transplanting. In both trials, the design used was a randomized complete block, with 4 replications in the greenhouse trial and 6 in the field trial. The degree of infestation of the tomato crop was taken into account, as an indicator of the reduction of infestation obtained by Crotalaria species compared to the fallow (control) The results were analyzed statistically using ANOVA 2. These indicate that all species tested in the greenhouse are resistant to the root-knot nematode. The field results revealed that the tested Crotalaria species reduced the infestation of Meloidogyne species, however not more than the fallow. (TRADUÇÃO NOSSA)