Growth Reduction of Apple Seedlings by Pratylenchus penetrans as Influenced by Seedling Age at Inoculation

Apple seedlings of different ages (1, 3, and 5 weeks) were inoculated with 6,900 Pratylenchus penetrans per seedling in 10-cm-diam pots in a growth chamber. Rate of growth suppression and total growth suppression of seedlings by P. penetrans were inversely proportional to seedling age at time of nematode inoculation. Younger seedlings were found to contain a higher number of nematodes per gram root.