EFFECT OF GAMMA-IRRADIATION AND HEAT ON ROOT-KNOT NEMATODE, MELOIDOGYNE-JAVANICA

effects of gamma-irradiation on the root-knot nematode Meloidgyne java nica were investiaged. A dose of 7.5 kGy killed all second-stage juven iles (J2) within 1 day after treatment. Egg hatch was completely inhib ited at 6.25 kGy. A bioassay on tomato measuring galling and egg produ ction was used to determine the infectivity of irradiated J2 and J2 ha tched from irradiated eggs. The J2 and eggs irradiated with dose of 4. 25 kGy did not induce galls or reproduce on tomato plants. When nemato des were exposed to combined irradiation and heat treatment, no synerg istic effect on J2 or eggs was measured. Heat treatment at 49 degrees C for 10 minutes or 20 minutes without irradiation immobilized J2 and prevented egg development. Irradiation rates needed to kill or incapac itate M. javanica were high and may be impractical as a quarantine mea sure.