SUGAR BEET NEMATODE (HETERODERA SCHACHTII) REARED ON AXENIC BETA VULGARIS ROOT EXPLANTS .I. SELECTED ENVIRONMENTAL FACTORS AFFECTING PENETRATION

Aseptic Beta vulgaris root explants were penetrated by 35-45 percent of axenized Heterodera ichachtii larvae added to agar culture media. Maximum penetration occurred at 25°C within 5 days of inoculation. Higher levels of inoculum did not increase percentage penetration. Concentration of constituents in the medium influenced penetration. When concentrations of vitamin stock and sucrose were increased percentage penetration increased. This response did not occur with the macronutrient salts stock. Monoxenic excised roots of the three Beta species B. patellaris, B. procumbens and B. webbiana demonstrated different degrees of resistance to penetration. © 1969 BRILL.