Which weed is primarily controlled by the herbicide 2, 4-D?

The primary control of dandelions is effectively achieved using the herbicide 2, 4-D due to its selective action on broadleaf plants. 2, 4-D is a systemic herbicide that specifically targets the growth hormones in dicotyledonous plants, disrupting their normal growth processes. Dandelions, being a broadleaf weed, are particularly susceptible to 2, 4-D, making it a popular choice for homeowners and landscapers aiming to manage these pesky plants without affecting the surrounding grasses, which are monocots.

In contrast, clover is also a broadleaf plant but may not be effectively managed by 2, 4-D without risk to desirable clover species. Crabgrass, on the other hand, is a grassy weed and requires different herbicide formulations for control, primarily pre-emergent herbicides targeted at annual grasses. Thistles, while also broadleaf, have varying tolerances and may not respond as predictably to 2, 4-D compared to dandelions. Thus, the efficacy of 2, 4-D in controlling dandelions positions it as the correct choice in this context.