CDFA Pest Prevention Plant Regulation Practice Exam

What is the scientific name for Johnson grass?

1. Agropyron repens

2. Tribulus terrestris

3. Sorghum halepense

4. Centaurea solstitialis

The correct answer is: Sorghum halepense

The scientific name for Johnson grass is Sorghum halepense. This perennial grass is known for its rapid growth and ability to spread aggressively, often becoming a problematic weed in agricultural settings. It thrives in a variety of soil types and is particularly well-suited to warm climates, which contributes to its wide distribution across many regions, especially in the southern United States. The other options do not refer to Johnson grass. For instance, Agropyron repens is the scientific name for quackgrass, an invasive species that can also spread quickly but is distinct from Johnson grass. Tribulus terrestris is commonly known as puncturevine, a different type of plant known for its sharp seed pods, while Centaurea solstitialis, or yellow starthistle, is another invasive species that impacts rangelands and other environments. Each of these plants has its own unique characteristics and implications for pest management and agricultural practices.