|Fraedrich, S - USDA FOREST SERVICE|
|Cram, M - USDA FOREST SERVICE|
Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 21, 2003
Publication Date: July 1, 2003
Citation: Fraedrich, S. W., Cram, M. M., Handoo, Z. A. 2003. Suitability of southern pines, other selected crops and nutsedge to an undescribed Longidorous sp. associated with stunting of loblolly pine seedlings. Plant Disease 87: 1129-1132. Interpretive Summary: Nematodes are microscopic worms that cause a ten-billion-dollar crop loss in the United States each year. Needle nematodes are an important group that causes serious economic damage to many kinds of plants. For example, one needle nematode species was recently found associated with stunting of loblolly pine seedlings at a Georgia forest tree nursery. One problem with needle nematode damage to pine seedlings is that foresters have no idea of the host range of the nematode and, therefore, what nonhost plants can be grown to reduce nematode numbers. In the present study, ARS and U.S. Forest Service scientists examined several plant species for their susceptibility to the needle nematode. Slash, longleaf and loblolly pines were hosts for the needle nematode. Red oak was not as suitable a host as pine. Small grain crops, including sorghum, sorghum-sudan hybrid, wheat, rye, and oats, were poor hosts for the nematode. Yellow and purple nutsedge, common weeds at the nursery, were found to be poor hosts. Tomato and cabbage, two crops previously grown at the nursery site, were poor hosts. The results are significant because they provide the first evidence that many crops are resistant to the nematode and are thus suitable for crop rotation practices to control the needle nematode. This research will be used by scientists, growers, action agencies, and extension personnel developing control strategies for nematode damage to forest tree seedlings.
Technical Abstract: An undescribed needle nematode (Longidorus sp.) has been associated with severely stunted loblolly pine seedlings at a south Georgia nursery. Containers with selected crop and weed species were infested with 100 or 200 Longidorus to evaluate host suitability. Nematode populations increased in containers with slash, loblolly and longleaf pine seedlings. Longidorus reduced the dry root weights of slash and loblolly but not longleaf pine compared to controls. Populations of Longidorus decreased on nutsedge and small grains including wheat, rye, oats, sorghum and millet; and in most experiments populations decreased to the levels found in fallow containers. Populations decreased on tomato and cabbage but increased slightly on red oak. The periodic removal of fields from production of pine seedlings and subsequent fallow or small grain cover crop treatments may be important management practices for this Longidorus sp. in seedling production areas.