Scientific name: Commelina benghalensis (L.) (Commelinaceae)
Domestic Programs Pest Evaluation. Arthur E. Miller, USDA-APHIS-PPQ, AERO, Raleigh, NC. November 26, 2001
Physical description: Tropical spiderwort is an annual or perennial creeping herb with white, burrowing rhizomes which produce underground flowers, fruits, and seeds; stems are fleshy, succulent and freely branching up to 3 feet long, usually hirsute, rooting at the nodes, the lower nodes usually developing naked underground shoots bearing small, white flowers; leaves simple and alternate, with closed sheaths often with reddish hairs; and flowers zygomorphic with the anterior (lower) 3 petals (sometimes white) much smaller than the 2 posterior (upper) lilac or bluish ones; seeds rugose-reticulate and often appearing sugar-coated.
Origin and North American Distribution: Tropical spiderwort is found in much as Africa, Saudi Arabia, India, Pakistan, Southeast Asia, the Pacific Islands to Australia, Cuba, Jamaica, the West Indies, Brazil, and French Guiana. In the U.S., it has been found in AL, CA, FL, GA, HI, LA and recently NC.
Quarantines: Tropical spiderwort (also called Benghal dayflower) is a Federal Noxious Weed.
Dispersal: The plants reproduce by seeds, stolons, and rooting at nodes of stems. One plant can produce as many as 1600 seeds.
Control: Property managers and cooperators may use these strategies:
Economic impact: Tropical spiderwort is a major host of cucumber mosaic virus. CMV is spread to tobacco by green and red aphids. Both spiderwort and CMV have continued to spread in Florida. The disease threatens entire tobacco crops in Florida because farmers cannot control it effectively with chemicals. Tropical spiderwort is an alternate host of peanut rosette virus, the fungal disease Puccinia commelinae, and the nematode Meloidogyne incognita.
Tropical spiderwort forms, dense, pure stands, smothering out other plants, especially low-growing crops. It has been reported recently as a problem in cotton in Alabama. In pastures, it grows rapidly over desirable grasses and legumes, competing with them for light and nutrients. In rice and other lowland crops it may be almost subaquatic withstanding flooding and waterlogged conditions, but they can also be found in cultivated lands, field borders, gardens, grasslands, roadsides, and waste places, and can become the dominant species in pastures.
Environmental impact: Tropical spiderwort is a weed of moist areas in the tropics and subtropics. It is classified as a wetland hydrophyte (plant which can take root in water-saturated soil), but the plant can live for extended periods after the soil has dried out. Tropical spiderwort grows from sea level to 1300 m elevation.
Benefits of control: Agricultural, forest, urban and natural areas can benefit from control and prevention of further spread of this FNW.
|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.