Aphelenchoides Xylophilus, N. Sp., a Nematode Associated with Blue-stain and Other Fungi in Timber »

The first observation of Aphelenchoides xylophilus, n.sp., the timber nema, dates back to 1929, when a small piece of wood that had been cut, in the process of roofing, from the top of a green pole of longleaf Louisiana pine (Pinus palustris Mill.) was received from Orange, Tex.^ This piece of wood had streaks of a bluish color caused by blue-stain fungi. The nemas were found in these streaks and in bordering portions. Larval specimens, males and females, were observed. Although they were not numerous, a dozen or more specimens could be found in a small portion of wood when soaked and dissected properly. Soaking the wood in water activated the nematodes, whereas drying the wood induced dormancy. Some tests showed revival of the nematodes after a dormancy of 1 year but not after 2 years. Later, through the courtesy of Ross W. Davidson, of the Division of Forest Pathology, Bureau of Plant Industry, there were received four different plate cultures of wood fungi in which nematodes had developed. All of these nematodes proved to be Aphelenchoides xylophilus. Three of the cultures were from a sawmill in Bogalusa, La., and were also obtained from blue-stained logs of Pinus palustris. These logs had previously been attacked by beetles of the genus Ips, which, according to Davidson, usually carry the blue-stain fungus Ceratostomella ips Rumbold, but which in these three cases contained a brown fungus belonging probably to the genus Trichosporium, of the *'Fungi Imperfecti.'' The fourth culture on which the same species of nematode developed was obtained from a pine tree {Pinus echinata Mill.) that had been recently killed by an attack of the beetle, Dendroctonus frontalis Zimm., near Fairfax, Va. In this case the nematodes originated in the interior of unstained wood, one-sixteenth to one-fourth of an inch below the insect galleries. The fungus here associated with this nematode is said by Davidson to be entirely hyaline and also to belong