Insect Resistance -
The efforts to produce insect resistant transgenic plants have been quite successful; insect resistant transgenic varieties of several crops are already in commercial cultivation in U.S.A.

Insect resistant plants usually contain a gene from the bacterium Bacillus thuringiensis. B. thuringiensis has been used since the World War I, particularly in Europe, to control some insect pests. B. thuringiensis strains are usually classified on the basis of serological tests, the serotype has very little relevance to the insecticidal activity of a strain.