Inoculation of seven pine species or hybrid seedlings with Korean isolates of pinewood nematode under greenhouse conditions

Abstract

• Seedlings of seven pine species or hybrids, Pinus densiflora, Pinus thunbergii, Pinus virginiana, Pinus echinata, Pinus koraiensis, Pinus thunbergii × Pinus massoniana and Pinus × rigitaeda ,w ere inoculated in a greenhouse with 100, 1000 and 10000 pathogenic nematodes, Bursaphelenchus xylophilus, to compare initial symptom development and to evaluate susceptibility to pinewood nematodes. • Genetic types were significantly different in the starting day of needle discoloration (χ 2 = 43.48; P < 0.001) and the period from nematode inoculation to seedling death (χ 2 = 32.85; P < 0.001), but treatment groups were not statistically different in the days from inoculation to seedling death in any of the pine species. • There was no relationship between seedling mortality and the number of nematodes recovered from infected seedlings. Only eight of the nematode-inoculated seedlings remained alive by day 83 after inoculation, including four seedlings each of P. echinata and P. × rigitaeda grown from bulked seed collections.