CDFA Pest Prevention Plant Regulation Practice Exam

Which is an example of a plant classified under secondary noxious weeds?

1. Goldenrod

2. Poison Ivy

3. Perennial sowthistle

4. Dandelion

The correct answer is: Perennial sowthistle

The classification of plants under secondary noxious weeds is based on their potential to cause harm to agricultural systems, ecosystems, and human health, though typically to a lesser extent than primary noxious weeds. Perennial sowthistle is recognized as a secondary noxious weed because it can invade crops and other cultivated areas, competing for resources and potentially affecting yields. Perennial sowthistle is particularly problematic due to its robust growth and substantial seed production, which enable it to establish quickly and spread widely. Its persistence in agricultural and disturbed settings illustrates the kind of challenges secondary noxious weeds pose, influencing management practices and cultivation strategies. In contrast, while plants like Goldenrod, Poison Ivy, and Dandelion may have their own impacts — such as allergic reactions from Poison Ivy or competition in lawns from Dandelion — they do not fall under the specific classification of secondary noxious weeds in the same way that perennial sowthistle does, making it a key example in this category.