Technique for Screening Cowpea Germplasm for Resistance to Root-knot Nematodes.

to the amount of root growth under the various conditions. At the termination of the experiment nearly all the nematodes were found within the tomato roots. T h e numbers found outside the root were somewhat greater at low light intensity than at high light intensity, particularly at the high inoculum level. Roots produced at the low light intensity were probably insufficient to support the high inoculum level. The re is some evidence (2) that placing a moderate stress on host plants may increase the reproduct ion of nematode parasites. We did not find that low light intensity had that effect with M. hapla. For studying nematode pathogenicity under controlled conditions we believe that factorial experiments allow a more complete understanding than single-factor studies.