TEMPERATURE EFFECTS ON THE ATTACHMENT OF PASTEURIA-PENETRANS ENDOSPORES TO MELOIDOGYNE-ARENARIA RACE 1

Pasteuria penetrans is a gram positive bacterium that prevents Meloido gyne spp. from reproducing and diminishes their ability to penetrate r oots. The attachment of the endospores to the cuticle of the nematodes is the first step in the life cycle of the bacterium and is essential for its reproduction. As a preliminary study to a field solarization test, the effects of temperature on the attachment of P. penetrans on Meloidogyne arenaria race 1 were investigated. Preexposing second-stag e juveniles (J2) of M. arenaria to approximately 30 degrees C in water before exposing them to endospores increased their receptivity to end ospore attachment when compared to treating J2 at 25 degrees C or 35 d egrees C. In tests with soil, highest attachment occurred when J2 were incubated in soil infested with endospores and maintained at 20 degre es C to 30 degrees C for 4 days. Heating J2 in soil to sublethal tempe ratures (35 degrees C to 40 degrees C) decreased endospore attachment. Incubating P. penetrans endospores in soil at 30 degrees C to 70 degr ees C for 5 hours a day over 10 days resulted in reductions of endospo re attachment to nematodes as temperatures of incubation increased to 50 degrees C and higher.