Screening Mimosa (Albizia julibrissin) Seedlings for Resistance to Nematodes and Fusarium Wilt. Alice Jacot McArdle, Horticulturist, USDA, ARS, U.S. National Arboretum, Washington, DC 20002. Frank S. Santamour, Jr., Research Geneticist, USDA, ARS, U.S. National Arboretum, Washington, DC 20002. Plant Dis. 70:249-251. Accepted for publication 3 September 1985. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1986. DOI: 10.1094/PD-70-249.

About 7,600 seedlings of Albizia julibrissin were used in screening procedures designed to select individuals resistant to the combined effects of the wilt fungus Fusarium oxysporum f. sp. perniciosum and the root-knot nematodes Meloidogyne incognita and M. javanica. Mortality increased significantly when Fusarium-inoculated seedlings were grown in media infested with the nematodes. Survival of seedlings derived from intercrossing among trees originally selected for wilt resistance was significantly higher than that of seedlings from unselected parents. Of 6,000 seedlings from wilt-resistant parents, 2,818 were alive after growing in a nematode-infested medium for 70 days after Fusarium inoculation. Six hundred of the most vigorous survivors were reinoculated with Fusarium, and although 312 of these were still alive after 7 mo, only 78 were symptomless the following spring. The surviving seedlings will be field-planted and evaluated during the next 5 yr to select wilt-resistant cultivars with superior horticultural characteristics.