Abstract
A recently discovered nematode,
Longidorus americanus, caused stunting of
Pinus taeda seedlings at a forest-tree nursery in Georgia, USA. In growth chamber experiments, L.
americanus significantly reduced the root size of I? taeda and P elliottii seedlings. Although the root systems of L.
palustris were not significantly reduced, it was found to be a host for L.
americanus. The field where damage by L.
americanus occurred was in continuous production of Pinus spp. and
Quercus alba seedlings from 1990 to 1998. Fumigation by MC33 (methyl bromide 67%/chloropicrin 33%) in the spring of 1998 and again in 2000 remedied the problem for only one year; the seedlings were severely stunted during the second production years (1999 and 2001). Growth chamber tests found that Quercus spp. (Q.
alba, Q.
rubra, Q.
falcata, Q.
virginiana, and Q.
nigra) were hosts for L.
americanus. The populations of nematodes declined with Q.
acutissima. Grasses used as cover crops in southern (USA) nurseries, including
Triticum aestivum, Secale cereale, Sorghum bicolor, Avena sativa and
Panicum ramosum are not hosts for L.
americanus. Weeds such as
Cyperus esculentus and C.
rotundus that are common in southern (USA) nurseries were also not suitable hosts for the nematode. A fallow study conducted in a field and in growth chambers suggests that L.
americanus does not survive in soil for extended periods (> 334 days) without a suitable host. Surveys for L.
americanus have determined that the nematode occurs in oak forests that border the nursery and in an adjacent pine seed orchard.
Keywords
Longidorus americanus,
Pinus sp.,
Quercus sp.,
cover crops,
Cyperus sp. fallow
Citation
Cram, M.M.; Fraedrich, S.W. 2007. Biology and management of
Longidorus americanus in a southern USA nursery. IUFRO Working Party 7.03.04: Diseases and insects in forest nurseries. The sixth meeting of the IUFRO. September 11-14, 2005.
