Agronomy Degree Practice Exam

Which grass species is a cool season annual and classified as a restricted noxious weed?

1. Common lambsquarters

2. Johnsongrass

3. Cheat

4. Wild mustard

The correct answer is: Cheat

Cheat, also known as cheatgrass (Bromus tectorum), is classified as a cool-season annual grass and is recognized as a restricted noxious weed in various states. Cool-season grasses thrive in the cooler parts of the year, usually in spring and fall, which matches the growth pattern of cheatgrass. This species is notorious for its rapid establishment and growth, leading to competition with desired crops and native vegetation. Being categorized as a restricted noxious weed indicates that cheatgrass can cause harm to agricultural crops and the environment, thus warranting management practices to control its spread. The combination of its growth habits, ecological impact, and the fact that it is an annual species makes it distinct in this context. In contrast, the other options do not fit the description of a cool-season annual noxious weed in the same way as cheatgrass does. Common lambsquarters, while it can be a weed, is a broadleaf plant. Johnsongrass is a perennial grass that thrives in warmer seasons, making it a poor fit for the cool-season classification. Wild mustard is a flowering plant that is also not classified as a grass. Therefore, cheatgrass stands out as the only species that matches all aspects of the question.