What does the term 'systemic' refer to in the context of herbicides?

The term 'systemic' in the context of herbicides refers to their ability to be absorbed by the plant and then translocated throughout its tissues. When a systemic herbicide is applied, it typically enters the plant through leaves, stems, or roots and moves through the vascular system to different parts of the plant. This allows the herbicide to affect both visible and hidden portions of the plant, including roots, stems, and even new growth. This characteristic is particularly effective against certain types of weeds that may have extensive root systems or that are otherwise challenging to control with contact herbicides, which primarily affect only the parts of the plant that they directly touch.

Understanding the concept of systemic herbicides is crucial for effective weed management strategies, as it helps practitioners choose the right type of herbicide based on the target weed species and its growth habits.