Producers should monitor aquatic herbicide usage around ponds
Ponds that are overgrown with pond weeds are not only unsightly but also very difficult to fish or even enjoy a cool summer swim.
Herbicides are a tool that can be used to help manage these weeds. However, while they are a quick means of knocking back pond weeds, care should be taken in the use and selection of herbicides, cautioned Marley Beem, Oklahoma State University Cooperative Extension aquaculture specialist.
"Using improper herbicides puts you and the environment at risk," he said. "We all like a bargain, but should not consider using herbicides that are not specifically labeled for ponds and other aquatic sites."
Only herbicides labeled for aquatic use have been tested for the safety of the environment, fish and people who eat those fish. Even with proper aquatic herbicides, there are some sites in which herbicides should never be used.
Beem said these include ponds that are excavated below the water table and fill from the bottom up; ponds in places like the bottom of gravel quarries or sandy river bottoms as groundwater may flow into someone's water well; and ponds that can overflow into public waters.
"Occasionally plant management is needed in creeks or flowing water situations. In this case, contact state agencies such as the Oklahoma Department of Wildlife Conservation before any application is made," he said. "When what you do on your property may affect others, be very cautious and proceed only with expert advice and approval."
OSU Cooperative Extension county agriculture educators will be able to help pond owners in developing a pond weed management plan.
Beem said it is essential that the landowner understand how to calibrate the application method, calculate the right amount of herbicide to use and be aware of the needed withdrawal time to protect livestock, swimmers and other pond-users.
"Another hazard in treating pond weeds is killing too many at one time, thereby causing so much plant decay that all dissolved oxygen is used up and your fish die," he said. "Take care in the selection (of herbicides) and use so that your enjoyment of the pond is not overwhelmed by problems resulting from an application gone wrong."