If you examine a tomato plant up close, you may notice that the foliage is covered in short, fine, hair-like structures. These hairs (what I affectionately dub tomato fuzz) are known as trichomes, and they serve a variety of functions and exist on many other plants as well.
On a tomato plant, several types of trichomes are found on the stems, leaves, and sepals.
One type works to reduce evaporation of water by trapping moisture on the surface of the leaf. Another helps shield the plant against environmental stresses like extreme temperatures, and yet another type (glandular trichomes) contains crystals and oils in the bulbous section of the structures, seen here on the ends.
It’s believed that these crystals and oils are part of the plant’s defense mechanisms. They produce an unpleasant feel, taste, and smell meant to protect the plant from insects that might feed on its foliage.
It’s a little ironic that what might be considered “unpleasant” by pests can in fact be so intoxicating to the rest of us!