One of the great advantages of dealing with thrips is that these tiny insects are largely specific to a particular plant. If avocado plants are contaminated, it is a case of "avocado thrips"; orange and lemon trees mean the culprit is a "citrus thrip." And so on. In each case, specific cultural, biological and chemical control options are available.

Citrus Thrips

Let's take as an example the aforementioned citrus thrip, a common problem in sunny western states such as Arizona and California. Commercial citrus groves are usually treated with a range of pesticides, preventing an outbreak. But backyard and residential citrus plants can be highly prone to a thrip attack..

For those looking to go "green" with the chemical treatment, kaolin is a good option. This product is made from clay minerals, but because it is more of a natural option, it kills only about 20 to 30% of the thrips it comes in contact with. Three applications through the growing season are required. Man-made chemicals to fight citrus thrips include cyfluythrin and dimethoate.

Onion Thrips

Again, each type of plant-targeting thrip requires different control methods. In the case of onion plant thrips, the good news is that "cultural" methods of containment are more widely available. The term refers to the natural environment within which the plants are seeded. In this case, spacing out cabbage, cauliflower and other plants properly from the onion rows will greatly help to control thrips.

Red onions are most susceptible to thrip attacks. Some varieties of Spanish onions are at the other end of the spectrum, having somehow developed their own natural tolerance to the small insect. An allowable number of thrips is 25 per plant. Experienced gardeners know to keep an eye on their crops of onion plants and monitor the infestations by placing a piece of paper underneath a sample plant, and shaking vigorously. Depending on how many small thrips fall out, it may be time to apply a round of the needed, plant-specific insecticide.