Preventative measures: Najas minor is reported as noxious and is regulated in Alabama, Connecticut, Maine, Massachusetts, New Hampshire, South Carolina, Washington. It is illegal to possess, import, purchase, sell, propogate, transport, or introduce N. minor in Minnesota. N. minor was included on a Washington Department of Agriculture list of quarantined species in 2000, and it is illegal to sell, trade, or transport in the state of Washington. Education and population monitoring are recommended to help prevent its establishment (DNR, 2007; Hamel & Parsons, 2001).
Chemical: Small scale herbicide treatments of endothall, dipotassium, and endothall mono have been conducted in hopes to provide “nuisance relief.” However, it has been reported that some non-target plant species have been affected as well. The following herbicides and brands were reported to yield excellent control for N. minor by the US army Corp of Engineers: diquat: Reward, Weedtrine-D; fluridone: Sonar AS, Sonar SRP, Sonar PR, Sonar Q, and Avast!; and endothall Aquathol K, Aquathol Super K, Hydrothol 191. N. minor was found to be completely unaffected by the herbicide butachlor (DNR, 2007; EL-EDRC, undated; Chattopadhyay et al, 2006).
Mechanical: The use of aquatic plant harvesters, large boats that cut and remove vegetation, has been recommended as a means to remove large quantities of Najas minor. Similarly, rotovators, basically large underwater rototillers that remove aquatic plant tissue and root crowns, are another recommended mechanical control. The use of hand cutters may be effective for smaller populations (EL-ERDC, undated).
Location Specific Management Information
Najas minor is listed as a 'Class C Noxious Weed' and is regulated in Alabama (USDA-NRCS 2010).
Najas spp. produce abundant seed that are dispersed primarily by waterfowl; the seeds can be also be carried inadvertently in bilges, trailers etc. The State Department of Environmental Protection has signs posted up at state boat ramps to make sure that boats and trailers are checked to make sure they are not carrying pieces of plants; a recent legislation (Connecticut Public Act No. 03-136) has been enacted that imposes fines on individuals found transporting plants this way, a public act also prohibts the sale of most invasive aquatic plants in Connecticut (Capers et al, 2005).
N. minor is listed as a 'Potentially invasive' weed and is banned in Connecticut (USDA-NRCS, 2010).
Najas minor is listed as a 'Prohibited' plant and is regulated in Massachusetts (USDA-NRCS, 2010; DNR, 2007).
Najas minor is listed as a 'Plant pest and Invasive aquatic plant' in South Carolina (USDA-NRCS, 2010).
Najas minor has been included on a List of Watch species in Vermont. It is being monitored and information to the public is being provided as part of the Vermont Wildlife Action Plan (2005).
2. Department of Natural Resources (DNR), Wisconsin, 2007. Aquatic Plant Brittle/Lesser/Bushy/Slender/Spiny/Minor Naiad; Waternymph
4. Environmental Laboratory (EL) U.S. Army Engineer Research and Development Center (ERDC), 2007. Najas minor All. (Slender Naiad) Herbicide Information
5. Environmental Laboratory (EL) U.S. Army Engineer Research and Development Center (ERDC), 2007. Najas minor All. (Slender Naiad) Mechanical Control Information
6. Environmental Laboratory (EL) U.S. Army Engineer Research and Development Center (ERDC), 2007. Information Sheet: Najas minor L. (Spiny Naiad)
8. Richardson, Robert J., 2008. Aquatic Plant Management and the Impact of Emerging Herbicide Resistance Issues. Weed Technology 2008 22:8–15
9. The Nature Conservancy (TNC), 2009. Invasive Plant Distribution Map Ohio: Najas minor Lesser naiad
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