DEVELOPMENT OF WINTER COVER CROPS IN SOIL INFESTED WITH THE NEMATODE TUBIXABA TUXAUA IN WESTERN PARANA, BRAZIL

This work aimed to study the effect of cover crops cultivated in the winter season on the population of Tubixaba tuxaua under greenhouse and field conditions. The green manures studied were seeded in pots containing sterile substrate (soil + sand 1:1) with capacity for 5 Kg of substrate. Four plants per pot were inoculated with 40 mixed stages of T. tuxaua when three mature leaves had been developed. The pots were grown under greenhouse condition at 25 degrees C. The experiments, pot and field assays, were run in a completely randomized design with 6 treatments and 5 replications. The treatments (cover crops) were Raphanus sativus var. oleiferus (oilseed radish), Lupinus albus (white lupine), Lathyrus clymenum (grass pea), Vicia villosa (hairy vetch), Pisum sativum var. arvense cv. 'Iapar 83' (field pea) and Avena strigosa (black oat). Field measurements were plant height, fresh shoot weight, fresh root weight, and initial and final population density of T. tuxaua. For the pot assay data collected were shoot height, root length and final population densities of T. tuxaua. The results showed that all plants studied, except the oilseed radish, were susceptible to T. tuxaua. Oilseed radish significantly decreased the population density of T. tuxaua in plots in the field experiment and also in pots. This is the first report of a cover crop (R. sativus var. oleiferus) with potential to be used in rotation with major crops for controlling T. tuxaua.