Weed management - Lessons form the USA

Aquatic weed management has a more than 100 year history in the United States, with the first efforts by the US Army Corps of Engineers to remove water hyacinth from southeastern United States waters in 1899. Through these efforts, several important lessons have been learned. First, plant management requires a plan of action that considers the level of infestation, makes site-specific management recommendations, and considers all potential techniques for use both spatially and temporally. A good plan also includes public involvement and education. Integrated Plant Management has become the model for aquatic plant management. It includes developing an understanding of factors that exacerbate plant growth, and methods to mitigate plant growth and enhance management success, including an understanding of target plant biology and phenology. In addition, most natural water bodies will require selective management, targeting the weed and minimizing the impact on desirable native plant species. Steady funding to invest in plant management is a necessity. Disruptions to funding will result in larger problems in the future. An important part of the investment is a consistent investment in applied research, with the target of improved plant control. In the United States, an attempt is made to consider biological, chemical, mechanical, and physical techniques for management of aquatic weeds. The use of these techniques is restricted by economic, environmental, and regulatory thresholds. While biological control may appear to be the preferred approach, many weeds do not have an effective biological control agent. Even effective biological control agents do not provide uniform control across the ecological range of a weed. Chemical control is still the most widely used technique in the United States. Chemical control is effective and relatively inexpensive, but increased regulatory restriction has impacted the use of herbicides in some areas. Mechanical techniques use machines to remove plant growth. In particular, harvesting is widely used as an immediate control to plant growth. However, harvesting is relatively slow and expensive, and may have a significant fish and aquatic animal bycatch. Physical control involves altering the environment to reduce plant growth. In the United States, this includes the use of benthic barriers, shading materials, and drawdown. Each of these techniques can be considered tools in our plant management toolbox, and all have their place and utility