A plant that continues to live from year to year. In many cases, in cold climates the tops die down but the roots and rhizomes persist. Examples: field bindweed, Canada thistle, quackgrass, dandelion.
Any substance or mixture of substances intended for controlling insects, rodents, fungi, weeds, and other forms of plant or animal life that are considered to be pests.
An application that kills weeds as the seeds germinate or as they emerge, either before or after the crop has emerged. (Application is before crop emerges.)