A New Kind of Potato

The consequences Adam and Eve faced after tasting forbidden fruit were severe. Eden had been the original low-maintenance – actually no-maintenance – garden. Without any work on the part of Earth’s first couple, plants grew and crops ripened. There were no weeds and no insect pests. But one unfortunate sampling from the Tree of Knowledge and everything changed. Thenceforth, sweat was needed to make a garden grow.
Genetic engineering may soon take us back to that pristine botanical world. Imagine a garden without insect pests. DNA that could synthesize insect toxin would be spliced into plant cell chromosomes. An insect that nibbled on such an immunized plant would die before it could do any damage. Everyone would have a garden of perfect plants, a personalized Garden of Eden.
But paradise, perhaps, will not so easily be regained. It is entirely possible that insects denied access to genetically altered plants will mutate into monster versions of their former selves. This, at least, is the argument
put forth in the latest issue of Organic Gardening.
A variety of potato called “New Leaf” has been developed that is immune to the ravages of the potato’s greatest nemesis: the leaf-eating grub of the Colorado potato beetle. This immunity has been acquired through genetic altering of potato DNA so that it synthesizes a toxin which deters many kinds of larval (grub and caterpillar) pests.
This toxin is manufactured, in nature, by Bacillus thuringiensis, a soil- dwelling bacteria that kills pest larvae without harming earthworms, beneficial insects, plants or people. It may be purchased at the nursery under various names, such as BT, Dipel or Thuricide. Engineering a potato that contains BT toxin in its leaves is comparable, in a way, to creating a dog that has flea-killing chemical in its blood; one bite and the offending pest is dead.
On the face of it, such a discovery is the ultimate demonstration of how nature may be subdued and bent to noble purposes. If crops could be made impervious to pests, they would be easier to grow; food production would increase and there would be fewer hungry people on Earth.
But the creation and distribution of pest-free plants could lead to plaguelike infestations in the future. It has been proven that insecticides do not provide 100 percent kill of target pests. Survivors and their offspring become increasingly resistant to the chemicals that are supposed to control them.
Organic Gardening’s Mike McGrath cites one example of this phenomenon: ”Growers in Florida and Hawaii who sprayed BT constantly in an attempt to control caterpillar pests wound up creating a caterpillar that could chew on BT-sprayed leaves without harm. And so the word went out – don’t overuse BT! Used with restraint BT would continue to be effective. But use it too often and you’d be working for the insects – helping them become immune to its effects!”
Perhaps plant researchers have been misguided by the many examples of human illness which can be prevented or cured by vaccination or drugs. With plants, the environment alone – as expressed in soil condition, air circulation, light availability and microclimate – can be manipulated or improved to virtually eliminate the occurrence of disease and insect problems.
As economic and social norms change, so will pest perception. It is well known that many backyard organic growers, whose soil is heavily enriched with kitchen compost, grow perfect plants. But composting is a labor-intensive process that large commercial growers won’t use. Should patterns of living change and people return to growing their own food, greater contact with the earth would lead to a fuller understanding of nature. People would learn, to quote Eliot Coleman, that “insect pests are not enemies but signals” that something is lacking in the environment. This day may not be as far off as some might think, since so many people would prefer to grow their own food – if only it didn’t take so much time and sweat.
Tip of the week: If you plan to grow peas this fall – and now is the time to plant them – prepare the soil with compost but do not fertilize after planting. Overfertilized peas produce lots of shoots and leaves but nary a pod. Some people never cook home-grown peas since they are sweetest when eaten immediately after picking, pods and all. Harvest when pods are still flat; once they begin to swell, their flavor diminishes.


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