Cohn, E., National and University Institute of Agriculture, Rehovot, Israel

The feeding and histopathology of the citrus nematode, Tylenchulus semipenetrans Cobb was studied on inoculated roots of the Israeli sweet lime, Citrus? aurantifolia Sw. and the sour orange, C. aurantium L. in aseptic cultures and on feeder roots sampled in the field. Different stages of tissue deterioration in the feeding zone around the head of the embedded female in the cortical parenchyma of the host root are described. Sections of infested feeder roots of the sweet lime invariably showed severe damage in the cortical tissue along the path of nematode penetration, associated with secondary fungal infection; this was rarely observed in the sour orange. The cells in the nematode feeding zone showed a depletion of starch granules. Starch breakdown occurred in the presence of homogenates of larvae and males of T. semipenetrans. © 1965 BRILL.