The corn plants containing the altered bacteria are receiving a continuous supply of natural insecticide, harmless to mammals, birds, and just about everything else except corn borers. For them, each nibble comes salted with deadly poison. The most ambitious of the genetic engineers have introduced Bt toxin-producing genes directly into the hereditary material of specific plants. Field trials conducted last year with cotton plants containing working Bt genes showed they were as protected from bollworm damage as were neighboring plants sprayed regularly with strong insecticides. All this is from just one bacterial species, and there are many other promising bacteria, fungi, and viruses.
Biological controls seem to combine the best of both organic methods and chemical pesticides.
These toxins kill, but they kill only the target pests. Before the turn of the century, we should be able to grow vegetables that won't need chemical spraying to win the battle of the bugs.