Introduction

Invasive Species Defined

What's Being Done

 National Invasive Species Information Center

Submodule 3: Invasive Plants

Invasive Plants and Agriculture

In agricultural settings, invasive plants are commonly referred to as “weeds.” Throughout the world, it is estimated that more time is spent removing weeds from farmland than any other activity; it is estimated that weeds annually reduce crop yields by over 10%.

In croplands, weeds pose problems that are unique to this setting such as:

• Weeds are highly competitive in an environment that is already designed to be ideal for plant growth; they can out-do crop plants for water, sunlight, space, and nutrients.
• Weeds decrease crop value by contaminating the harvested produce and crop seed for replanting
• Weeds limit the ability of farmers to use crop land by reducing land usage and crop rotation
• Weeds can provide habitat for pests, and then introduce these pests to crop plants
• Weeds disrupt the mechanized handling of crops by, for example, clogging harvesting machines and making seed cleaning machine ineffective.
• Weeds increase the need for water by crops plants.
• Weeds reduce the value of farmland.
• As weeds become resistant to herbicides, controlling them becomes more difficult.