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FARM POND AQUATIC WEED CONTROL RESEARCH SOUTHERN INDIANA FORAGE FARM
Research Progress Report 16 May 1962, Project 1020
Lynn Guse, Department of Botany and Plant Pathology
In an attempt to improve the water quality in ponds on the Forage Farm, various aquatic herbicides have been applied to aquatic weeds found on the farm to evaluate their weed control effectiveness and residue persistence. The primary aquatic weeds observed in the ponds over the past 3 years were cattails (Typha latifolia) and filamentous algae. Practically no submerged, rooted aquatic weed problem exists at the present time. Fortunately, the weed problem in the water, filamentous algae, can be chemically controlled with safety even though the treated water may be consumed by humans and livestock. For algae control, copper sulfate (blue vitriol) is recommended at the rate of 2 ppm 1/ or 5 1/2 pounds per surface acre per foot of average depth, or 17 pounds per surface acre. The material may be applied in a water spray or by dragging the material through the water in a burlap bag. The material should be applied when the algae first appears in the spring and re-treatment might be necessary as re-growth occurs later in the summer.
It has been observed that the cattails in the ponds are rapidly encroaching into the ponds. Their contribution to the organic matter in the ponds and the rapid evaporation of the pond water is considered objectionable thus their eradication is suggested. Attempted physical removal of the cattails with a rake-like device has been considered a failure because of difficulty encountered in removing all the viable root parts.
Figure 1. Cattails transpire large quantities of water thus cause serious losses in areas of water shortage; add considerable undesirable organic matter to the water source and hinder water recreation. A single head produces an average of 222, 000 seeds.
When water is to be used by humans and/or livestock, in areas where cattails are a problem, 15 pounds of dalapon in 100 gallons water should be sprayed on the foliage after the cattails are 2 to 3 feet tall. Effec -tive control of cattails can also be obtained by spraying on 10 pounds of amino triazole in 100 gallons of water at the time the heads appear until they are fully formed; however, this material cannot be used if the water will be consumed. Both dalapon and amino triazole should be sprayed to wet the vegetation thoroughly.
1/ ppm (parts per million) is the parts of active ingredient applied per million parts of water. One acre foot of water weighs about 2, 700, 000 pounds therefore, 2.7 pounds of active weed killing chemical is one part per million (1 ppm).
PURDUE UNIVERSITY Agricultural Experiment Station Lafayette, Indiana