Domestic Programs Pest Evaluation. Arthur E. Miller, USDA-APHIS-PPQ, AERO, Raleigh, NC. October 6, 2003
Scientific name: Cuscuta japonica Choisy (Cuscutaceae)
Physical description: Dodders are annual holoparasitic vines which attach to and penetrate host plants of diverse families by peg-like haustoria. There are over 150 species world-wide and the species are similar. Vegetative features are of little value in identification. The specimens collected during survey should have flowers and/or seeds present for identification, but should be handled carefully to avoid seed dispersal.
Japanese dodder is a parasitic annual that is rather fleshy and smooth. It may overwinter by seed or established stems on perennials. The stems are circular and much-branched. The stem color is pale yellow with red spots and striations. The leaves are scale-like and about 2 mm long. The numerous flowers are pale-yellow and on very short stalks. The seeds are 2.5 to 3 mm in length and 2 to 3 mm in diameter, variously dented, and range from pale straw to blackish in color.
Origin and North American Distribution: It is native to Asia. Three introductions found some years ago on kudzu apparently have been eradicated in San Antonio, TX, in Quinsy, FL, and at Clemson University, SC. During 2001, it was discovered on several properties in Houston, TX. The hosts there include broadleaf woody species. It has killed an oak tree.
Quarantines: The Federal Noxious Weed List includes Cuscuta spp. other than native or widely distributed species. Dodder seeds are commonly intercepted contaminants of commercial seed shipments entering the United States. Any seed shipment found to contain seed of any dodder is denied entry and the commodity is either devitalized or returned to country of origin. Dodder is also listed in various state noxious weed laws.
Dispersal: Long distance dispersal is by contaminated crop seed. Seed has been found being imported and distributed as a medicinal herb. Dodder seed may be spread to nearby areas by animals, water, equipment, and other means.
Control: Property managers and cooperators may use these strategies:
Economic impact: Dodder affects the growth and yield of infested plants. Losses range from slight to complete destruction of the crop in infested. Both woody and herbaceous hosts are attacked. Japanese dodder parasitizes orchard fruits, eggplant, kudzu, potato, pumpkin, purple osier (Salix purpurea), soybean, and tobacco.
Environmental impact: A survey along the coast of Hokkaido, the large northern island of Japan, revealed that Japanese dodder parasitized a total of 32 different species of wild plants belonging to 30 genera of 16 families, as well as 7 crop species.
|Bargeron, C.T., D.J. Moorhead, G.K. Douce, R.C. Reardon & A.E. Miller |
(Tech. Coordinators). 2003. Invasive Plants of the Eastern U.S.:
Identification and Control. USDA Forest Service - Forest Health
Technology Enterprise Team. Morgantown, WV USA. FHTET-2003-08.