Glandular Hairs

Glandular hairs on alfalfa stems inhibit small insect from crawling over the plant.  Some of the glandular hairs contain toxic substances, and some are simply sticky and trap small insects.  Using this trait has been the best mechanism to develop resistance to the potato leafhopper.  Most alfalfa plants have no pubescence (hairs) or the hairs are sparsely spread over the surface of the stems and leaves.