Owing to the failure of the potato crops in South Lincolnshire in areas where the eelworm Heterodera schachtii was known to occur, investigations were undertaken by this Institute to determine to what extent the nematode was responsible for the losses incurred, and to discover some method for its control. This work was begun by Dr. D. O. Morgan in the autumn of 1924. In order to gain a general knowledge of the natural conditions under which the nematode occured, and to obtain some indication of the most promising lines on which fundamental research might be carried out, extensive field observations were made. By this meand much data was accumulated which has been of great service in the carrying out of later laboratory adn field studies.