Root Extracts of Pangola Digitgrass Affect Egg Hatch and Larval Survival of Meloidogyne incognita.

sities that were lower than initial densities (Fig. 2, Tab le 1). Assuming a similar extraction efficiency for the Washington State population, the general nature of the relationship between initial and final nematode densities on Washoe was similar to the Italian population. Tile final densities of J2 of the Italian populat ion were lower than the initial densities at all inoculum levels in the resistant Nevada Syn XX (Fig. 2, Table 1). Only a few eggs in the American final populat ion were detected on the resistant Nevada Syn XX (Table 1). T h e results of these experiments confirnl a low tolerance limit for Washoe seedlings to the Washington State M. hapla population. T h e tolerance limit to tile Italian populat ion was slightly higher than previously reported (6), perhaps because of more uniform distribution of inoculum about root systems. T h e data confirm the resistance of Nevada Syn XX to other M. hapla populations in addition to that reported by Griffin (4). However, early growth of the resistant Nevada Syn XX was inhibited by high numbers of the Italian and American M. hapla populations, even though nematodes reproduced poorly or not at all (Fig. 1 A-B, Table 1). The highest nematode densities used in these studies, althougll generally greater than those under field conditions, caused growth suppression of both cultivars in the seedling stage. Consequently, stand establishment of the 4, October 1983