Root-knot-nematode injury on Hicks was equally severe when it was inoculated with M. javanica or M. incognita acrita as shown by root galling severity, depressed yields and depressed market values. NC 95 and 410 were free of root-knot galls when inoculated with M. incognita acrita but suffered significant yield depressions from early retarded growth when high levels of artificial inoculum were used. A lower level of natural soil infestation, however, caused less root-knot injury on these tobaccos than it did on Hicks. NC 95 and 410 were resistant to M. javanica as shown by slight galling in contrast to Hicks, which was severely galled. High levels of inoculum with M. javanica also caused early retarded growth and reduced yields. Market values were generally correlated with yields which were depressed as nematode damage increased. The data indicate that root-knot resistance under high levels of infestation should not be evaluated from root galling alone.

(Full article published with kind permission from "Tobacco International")