Texas FFA Nursery Landscape Practice Exam

Glyphosate is a non-selective herbicide known to kill:

1. Both annual and perennial weeds

2. Perennial weeds

3. Annual weeds

4. Any green plant that it contacts

The correct answer is: Any green plant that it contacts

Glyphosate is classified as a non-selective herbicide, which means that it does not differentiate between types of plants. When glyphosate comes into contact with any green plant material, it disrupts the synthesis of essential amino acids necessary for plant growth. This leads to the death of the plant. Because of its mode of action, glyphosate effectively kills all green plants, including grasses, broadleaf plants, annuals, and perennials. In contrast, the other options suggest classifications that imply selectivity. While glyphosate can kill both annual and perennial weeds, the defining characteristic of its action is its ability to target any green plant, regardless of whether it is an annual or perennial type. Therefore, the option that states it kills "any green plant that it contacts" accurately captures the broad-spectrum effect of glyphosate, underscoring its non-selective nature.