Gardeners should use plant species and varieties that are well adapted to the local soil pH, drainage or temperature. Moreover, plants should be selected which show resistance to the local pests. Host plant resistance is a term for distinguishing plant varieties which exhibit less insect damage when compared to other varieties under similar growing and pest population conditions. Host plant resistance is frequently interpreted as meaning "immune to insect damage." Actually host plant resistance can act in several ways and few plants are totally immune to insect damage.
There are three major ways that host plant resistance works: tolerance, non-preference, and anti-biosis.
Tolerance is presence if a strain of plants survives or produces better than a standard variety when the same amount of pests are present. Tolerance is exhibited when a large insect populations are supported on a plant without suffering appreciable damage.
Non-preference occurs when a variety is attacked less frequently than a standard variety even though pests can select either variety. Some varieties may be less "tasty" to insect pests, or may possess certain physical or chemical properties which discourage insect feeding or egg-laying.
Anti-biosis occurs when a plant has physical or chemical characters that inhibit the growth of a pest. Plants with tough stems or with chemicals that are difficult for a pest to digest are examples of anti-biosis in plants.
These factors may not be easily recognized in a particular variety of plants. The outcome of resistant variety is that the plant just grows or produces better than another variety.
Before buying seeds or plants, check seed catalogs for information on resistant varieties which will grow well in your area. Check also with your county extension agents as well as local seed dealers and nurserymen for best varieties to grow. Your experience with different varieties will indicate the ones best suited for your garden.
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