Most lake associations rely on a professional lake management company to identify problems and to treat when appropriate. Lake associations can make this relationship more effective by giving firsthand observations to their management company. Some easy ways to do this are to report changes in Secchi measurements and identify areas of the lake that have an abundance of vegetation. Secchi measurements are a great way to keep track of water clarity and spot a potential bloom early on. When reporting vegetation to a lake management company, it is important to know what type of vegetation is becoming a problem.
NJCOLA has partnered with the Rutgers Environmental Steward Program to create articles on ten of the most common aquatic nuisances found in New Jersey lakes. Early identification of nuisance vegetation is important to make sure you are not eliminating desirable species. Sometimes a treatment for an aquatic plant that is not very troublesome can open the door for a non-native species to take over. Understanding what type of aquatic plant you are dealing with can help lake associations identify dangerous, non-native species and treat them before the problem gets out of hand. Conversely, a native species that may temporarily cause an eyesore could be a benefit to your lake and should remain untreated.
The following articles were created to help identify the type of vegetation you are dealing with and then explain a little bit about each type of aquatic plant. At the end of each article, treatment options are discussed and links for further information are provided. These articles are not meant to be a guide to recommended treatments. They are written to assist lake associations to give informed feedback to their management companies. After all, few companies will have the daily interaction with a lake that is enjoyed by a lake association and their various teams.
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Excessive weed growth is a problem for swimmers and boaters. So we do our best to maintain just enough plant life to compete with algae for lake nutrient, but not so much that it interferes with lake recreation and aesthetics. Weed growth is minimized when we are able to maintain low nutrient levels, both from the sediment and from inlets. However, if we experience excessive growth, there are two herbicide approaches that are effective. One is a systemic herbicide, like Sonar, which is applied early, before weeds get tall. This minimizes weed growth and in turn it minimizes the amount of dead weeds falling to the bottom of the lake adding to the internal biomass. The other type of herbicide is a contact herbicide like Reward. Contact herbicides are applied when weeds are developed, even to the surface. The weeds are killed on contact and die off pretty quickly. Both these herbicides are applied in the spring, and they may require two treatments.
Hydro-raking can help reduce weed growth by removing some of the nutrient available to plants. It also helps remove dead plant life and shoreline leaves, again taking away nutrient for further growth. Drawdown may also help if the lake bottom is exposed long enough to freezing weather. To the extent we can remove other lake bottom “sludge,” we can also cut back on weed growth. Shading with products like Blue Dye help to cut back on weed growth as well as algae growth by limiting UV light. The challenge is to find that balance which allows some native species to flourish while keeping weed growth from interfering with swimming and boating.