Word: harpaz
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Shortly before he reported for duty with his reserve unit during the six-day Arab-Israeli war, Hebrew University Scientist Isaac Harpaz, 42, proclaimed victory over a less obvious threat to his country. For several years hybrid corn plants in Israel-and in several European countries-had been under attack by a mysterious disease that dwarfed their growth, roughened their leaves and often completely destroyed them. The disease has now been routed, Harpaz reported, by his discovery that a little procrastination in planting will pay large dividends in healthy corn...
After 70% of Israel's hybrid corn crop withered away in 1958, the Israeli Ministry of Agriculture, suspecting that the disease was spread by an insect, called on Harpaz for aid. By 1959 Harpaz had discovered that the corn blight -which he straightforwardly named Rough Dwarf Maize Disease-was caused by a virus. Coping proved more difficult...
Mistaken for Grasses. Supported by an $80,000 grant from the U.S. Agriculture Department, which was concerned about the possibility that the disease might spread to the U.S., Harpaz finally identified the virus carrier as a tiny plant hopper named Delphacodes striatellus. The insect, he discovered, was not particularly fond of corn, preferring the sap of barley, wheat and oat plants during winter and wild grasses in the summer. But while moving from its winter-to summer-plant hosts, the plant hopper frequently plunged its stylet into young corn seedlings in the mistaken belief that they were wild grasses...
Spraying seedlings with chemicals to control the plant hopper would have been prohibitively costly. Instead, Harpaz turned to the virus itself. Further research revealed that it was extremely sensitive to heat, ceasing all reproductive activity within the plant hopper when the temperature reached 76°F. To Harpaz, this suggested a simple solution: instead of in early April, hybrid corn should not be sown in Israel until late May. Thus when the seedlings emerged early in June, he reasoned, the few viruses left in the plant hoppers' salivary glands would be too sluggish to infect the corn...
...test Harpaz' findings, Israeli farmers last year planted some of their hybrid corn in early April, the rest late in May. There could be no doubt about the results. Although 45% of the plants sown in April came down with Maize Disease, only 3% of the May plants were infected. Similar tests, adjusted for local temperature variations, have also proved successful in Czechoslovakia, Bulgaria and Italy, where corn farmers are learning that they can reap more by sowing later...
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