(Beyond Pesticides, October 15, 2008) Researchers have developed a potential new method of making plants significantly more resistant to pests. Scientists from Lancaster University (UK) have conducted early trials whose results have yielded promise to greatly reduce pesticide by first treating seeds with a chemical that is naturally produced by plants.
This new method involves dipping seeds in jasmonic acid, a plant derived chemical that provides a natural defense against pests. When threatened by plant-eating insects, plants release jasmonic acid as a chemical signal to warn other parts of the plant to mobilize their pest defenses in order to make the plant difficult to digest. Jasmonic acid has long been used as a repellent for pests like mites, caterpillars and aphids when sprayed onto crops. Jasmonic acid however, also acts as a growth inhibitor and sprayed plants do not grow very well, but scientists at Lancaster University’s Environment Centre have found that plants grown from seeds first dipped in jasmonic acid are also more pest resistant without any loss of growth.
The best results were on tomato plants, where attacks by red spider mites were reduced by 80%, aphid attack was reduced by 60% and caterpillar damage was down by a third. Promising results were also obtained on sweet pepper where aphid attacks were reduced by 70 per cent, and caterpillar damage to wheat was reduced by 65 per cent. Meanwhile on maize, caterpillar damage was reduced by 38 per cent.
“We were investigating the mechanisms by which wild plants defend themselves against pest attack to get a better understanding of what works in nature. We were spraying the leaves of our plants with jasmonic acid and wondered what would happen if we treated the seeds instead. It seemed unlikely that it would work but we were amazed to discover that it did – tomato plants were protected for about two months after they germinated,” said lead researcher Nigel Paul, PhD, of Lancaster University.
Large-scale trials of this new technology are expected this year and by the end of the year, the researchers should know whether or not a commercial product will go into development. In the meantime, work is being put into developing new applications for the technology, including investigating its value in disease control.
Until now attempts at creating pest resistant crops involved genetically modified (GM) technology. Many proponents of GM technology believe GM crops can alleviate the current crisis in food supply. However studies have shown that GM crops can lead to a large increase in pesticide use, due to increased insect resistance. GM crops have also been found to harm aquatic ecosystems and contaminate organic and non-GM crops.