The root-knot nematode, Meloidogyne incognita is a serious parasite on cotton. The nematode establishes itself as an obligate parasite by inducing the formation of giant cells in host tissues. We believe that giant cell initiation and maintenance are brought about by factors in the nematode's stylet exudate. Thus we are attempting to characterized this exudate to further our understanding of pathogenesis. Adult female nematodes, excised intact from host roots, are incubated for 18H in 0.07M phosphate buffered (pH 7.1) saline to allow stylet exudate to accumulate. The exudate accumulates as a micro droplet (<3nl) at the oral aperature of the nematode. To retard bacterial contamination buildup the excised nematodes are subjected to 15 sec pulses of 302 nm irradiation every hour during the exudate accumulation period. Approximately 20% of the nematodes excised from host roots accumulate collectable amounts (>0.5nl) of exudate. Accumulated exudate, collected with a micromanipulator, has been used to produce anti-exudate antibodies in white mice. The anti-exudate antibodies have been conjugated to goat-anti mouse antibody labeled with fluorescent and colloidal gold markers. The conjugates are being used as probes in immunohistochemical studies on site of synthesis and storage of exudate materials in the nematode and to detect sites of exudate in host cells. Collected exudate has also been electrophoretically characterized for protein composition. Of six major protein bands detected, one appears to be a glycoprotein. Qualitative differences in protein composition in exudates from different species of root-knot nematodes do not seem to exist. Amino acid analyses of exudates did not reveal the presence of any unusual amino acids. Peroxidase activity was not observed in any stylet exudates.