EVALUATION OF PASTEURIA-PENETRANS ALONE AND IN COMBINATION WITH OXAMYL, PLANT-RESISTANCE AND SOLARIZATION FOR CONTROL OF MELOIDOGYNE SPP ONVEGETABLES GROWN IN GREENHOUSES IN CRETE

In a plastic polytunnel in Crete, spores of Pasteuria penetrans (Pp) c ontained in powdered tomato roots were incorporated in 6 1 of soil at planting sites at a concentration of 25 000 spores g-1 of soil. The so il had been artificially infested with a natural population that was a mixture of Meloidogyne javanica and M. incognita. In one experiment t he root galling and egg production on a nematode-susceptible tomato va riety was significantly less in plots treated with Pp and oxamyl than in untreated controls. Pp and oxamyl had an additive effect in combine d applications. Yields, however, did not differ significantly between treatments. There were reductions of nematode populations and root gal ling on a subsequent cucumber crop, which became severely damaged. Thi s had to be curtailed because of premature senescence and death in the nematode-only control plots. The presence of Pp in 65-75% of mature f emales and on free-living juveniles in soil indicated that Pp had pers isted in the soil and had increased over the two crops. The efficacy o f the parasite was enhanced by oxamyl applications. In one experiment, nematodes failed to develop in a resistant tomato cv. and there was n o beneficial effect from application of Pp and oxamyl. In a subsequent cucumber crop planted in the same plots, nematode population remained small in all treatments but 16-18% of mature females in Pp-treated pl ots were infected with the bacterium and 25-40% of J2 in the soil had spores attached to them. In another experiment when a solarization tre atment was included, root galling, egg production and J2 in soil were significantly less after growing cucumber for 10 weeks in Pp, oxamyl a nd solarization treatments. In this case the efficacy of Pp was enhanc ed after oxamyl application and probably in solarized soil; when all f actors were combined the treatments were additive.