You can make the professionals’ job easier and cut your treatment bills by reducing the nutrients getting into a body of water.

By Jeff Burbrink
Extension Educator, Ag & Natural Resources, Purdue Extension LaGrange County

Jeff Burbrink

LAGRANGE — Between Memorial Day and Labor Day, extension offices often get questions about weeds in ponds and lakes. I would like to share some thoughts on aquatic weed control.

First, aquatic weed growth is very temperature driven. Once water temperatures exceed the 60–65-degree F range, it becomes increasingly difficult to get the situation reigned in. A quick internet check found that many of our monitoring sites are already in mid-60s. Above that range, you have to be very careful. Killing too many weeds at once will use up oxygen in the water as the plants decay, and that will lead to a fish kill. The ugly part of that: the big fish need more oxygen per pound of their body weight, which means the big fish die first.

Second, if you want to use herbicides to control aquatic weeds, you must get the plant properly identified. The world of aquatic weeds is complicated. There are at least seven different categories of aquatic weeds in our area, and there is a category of herbicide for each type of weed. Select the wrong product for your weed, and you can waste a lot of money and time. Most callers just say they have algae. That is a signal the person probably should hire the job done! Here are 2 good sites with information on identifying and treating aquatic plants: https://shorturl.at/ivyT0 and https://shorturl.at/gkwTV

Third, and maybe the most important, I get nervous when someone tells me they live on a body of water shared with other people, and they want to treat the water at their site. Why the worry? Water moves. Herbicides will move with the water. How do you keep the product on your site? If you don’t know what you are doing, or don’t select the right product, or do not have the equipment to make the application, you are inviting the wrath of the neighborhood upon you, possibly doing environmental damage and incurring large fines from regulatory agencies.

For those reasons, I strongly suggest that people who share shoreline or streambanks with others hire the work done. We have capable professionals in the area who deal with aquatic weeds for a living. Rather than wrecking your summer, turn these jobs over to the pros. I know it is expensive. Aquatic herbicides are expensive to produce and very hard to get legally approved, and for good reason; they need to be thoroughly checked out. It takes specialized skill and equipment to do this job right. Let a professional take the risk!

I even squirm when I hear about some people treating their own ponds that are completely contained on their own property. There are just so many things that can go wrong, and people without experience, proper equipment, good timing, and bad advice can really cause a lot of issues with a pond.

You can make the professionals’ job easier and cut your treatment bills by reducing the nutrients getting into a body of water. I once read that 1 pound of phosphorous can spawn 500 pounds of weeds. That is a crazy number! Nitrogen, too, can stimulate weed growth.

If you have a poorly designed septic system, like a guy I heard about with a 55-gallon drum “septic system” and a tile running off to parts unknown, you are a part of the issue. If you fertilize your lawn right up to the waters edge and see fertilizer granules splashing as you push the spreader, you are part of the problem. If you fertilize your driveway and street, and the fertilizer runs off in the stormwater, you are part of the problem. If you farm near a lake or stream and water containing soil or manure runs off, you are affecting the water quality for everyone else.

Of course, no one person can control everything. A 500-year storm is going to wreak all kinds of havoc, and no one can do a thing about it. But, when people know there is an issue, and do not adjust behavior, that is a disregard for the others around them.

I think the key word or concept is stewardship. I believe, maybe naively, that most of us want to leave this world a better place than how we entered it. But as imperfect beings, our self-interests sometimes override our sense of duty. As our world gets more crowded, it becomes more important for us to be good stewards. Understanding, actual changes in behavior, and less finger pointing are key to being better stewards of our world.