Rearing migratory endoparasitic nematodes in citrus callus and roots produced from citrus leaves

Radopholus similis and Pratylenchus coffeae were reared on callus and roots developed from citrus leaves. Callus formed best when leaf petioles were immersed in Astatula fine sand and the leaves were sprayed daily with 4 ppm 2,4-D solution and maintained at 25 or 30 C. The nematodes completed one generation in 20 days at 25 C. Highest populations of R. similis (1,127) occurred after 50 days, and the highest for P. coffeae (619) after 70 days. Leaf-callus cultures from R. similis-resistant citrus rootstocks showed the same degree of infection as susceptible rough lemon callus after 30 days.