OPTIMAL LEVELS OF MELOIDOGYNE-INCOGNITA INOCULUM FOR INFECTION OF TOMATO AND PEACH IN-VITRO

Penetration of second-stage juveniles (J2) of Meloidogyne incognita in to tomato root explants and in vitro propagated peach plantlet roots w ere compared. Five inoculum levels were used: 25, 50, 75, 100, and 200 J2 for tomato; and 50, 100, 200, 500, and 1,000 J2 for peach. The gre atest root penetration into tomato was 30%?c at the 75 J2 level, but t he maximum penetration into peach roots was only 8% at the 200 J2 leve l. The difference (P = 0.05) in penetration of M. incognita at all ino culum levels into these two hosts indicates that penetration versus in oculum density for in vitro studies need to be determined for differen t plant species.