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|Title:||US Department of Agriculture/Corps of Engineers cooperative aquatic plant control research--Annual report for FY 1983 : Chemical control technology|
|Authors:||United States. Agricultural Research Service.|
United States. Department of Agriculture.
Aquatic Plant Control Research Program (U.S.)
Van, Thai K. (Thai Khac), 1941-
Steward, Kerry K.
Jones, Ann O.
Conant, Richard D.
|Keywords:||Aquatic plant control|
Controlled release herbicides
|Publisher:||Environmental Laboratory (U.S.)|
Engineer Research and Development Center (U.S.)
Abstract: This report presents the results for FY83 of an ongoing program to evaluate chemical formulations for their potential use in aquatic plant management and control. Of the several controlled release herbicide formulations evaluated in FY83, two monolithic polycaprolactone fibers containing fluridone have been found to have significant potential. These fibers, designed to maintain herbicide-plant contact over a period of four to six weeks, were proven effective in controlling hydrilla (Hydrilla verticillata Royle) at 2.2 kg a.i./ha (active ingredient per hectare) in flowing water in large outdoor aquaria. Under the same conditions, the commerical formulation Sonar® 4AS provided no hydrilla control. Two silicate capsules of dichlobenil showed promising results in the laboratory and were selected for evaluations in large outdoor aquaria in which long-term control of hydrilla regrowth was assessed. Research concerning application of glyphosate indicated that decreasing carrier volume increased phytotoxicity of glyphosate to waterhyacinth, mainly by enhancing herbicide retention and penetration. A treatment of 1.7 kg a.e./ha (acid equivalent per hectare) glyphosate in 438 L/ha water carrier resulted in faster and longer lasting control than did 2.8 kg a.e./ha in 935 L/ha. Long-term effects from glyphosate on torpedograss in standing water were significantly reduced compared to activity achieved on ditchbanks. Studies with 14-C-glyphosate indicated that herbicide translocation was impeded in standing water. Sulfumeturon at 0.02 kg a.i./ha completely eradicated waterhyacinth in a 0.07-ha pond in Fort Lauderdale. Residue analyses indicated that levels of 1.3 to 1.6 μg/L sulfumeturon were present in water 24 hr after application. Herbicide residues in water then decreased rapidly and were detectable in only one of six samples (1.1 μg/L) two weeks after treatment. Residues in all sediment samples and all fish samples were below detection limits.
|Appears in Collections:||Miscellaneous Paper|