Which of the following pesticides is effective against woody and perennial plants?

2,4-D is an effective herbicide that targets broadleaf weeds and is known for its ability to control a wide range of perennial and woody plant species. It functions as a systemic herbicide, meaning it is absorbed by the plant and translocated throughout its tissue, which is particularly useful for tackling established perennial plants and woody species that can be more resistant to herbicide treatment.

This effectiveness against woody and perennial plants stems from its mode of action, which interferes with the plant's natural hormonal processes, leading to uncontrolled growth and ultimately, plant death. This makes it suitable for managing invasive species and controlling unwanted vegetation in various landscapes.

In contrast, other options like Clethodim, Diclofop, and MCPA have more specific uses. Clethodim is primarily used for grass control and is not effective against broadleaf or woody plants. Diclofop is selective for grass weeds and does not target woody species effectively. MCPA is mainly effective against broadleaf weeds but may not be as effective against perennial plants as 2,4-D. Thus, the choice of 2,4-D reflects its broader efficacy in managing both woody and perennial plant proliferation.