Word: insects
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...pesticides will be beneficial to the farmer. Many scientists believe that the introduction of pesticides like DDT, which promised easy pest control, actually intensified the problem by encouraging the abandonment of such traditional?and sound?agricultural practices as rotating and diversifying crops and adjusting times of planting to avoid insect infestations. "Insecticides have failed not because of any inherent weakness in the concept of reducing insect populations by chemicals," writes Vincent Dethier of the University of Massachusetts in his newly published book Man's Plague? (Darwin Press; $9.95). "They have failed because of misuse, because of the unrealistic goals...
...treadmill, entomologists are advocating a different approach to pest control. They no longer speak of eradicating insect species: the costs both in dollars and environmental side effects are simply too great, the chances of success too small. What they are after instead is what George Georghiou of the University of California at Riverside calls a Mexican standoff, in which insect depredations could be kept small enough to be acceptable economically...
...strategy for achieving this goal is called integrated pest control, or ICP. Advocates of ICP leave room in their antibug arsenals for insecticides. The more potent pesticides will always be needed, they say, to cope with any insect problem that suddenly gets out of hand?a mosquito infestation brought on by an unusually hot, damp summer, for example, or an unexpected attack on a particular crop. But entomologists and agricultural scientists now believe that the most promising weapons for the battle are biological controls, which can be aimed at specific insect targets without adversely affecting either humans or the environment...
...station at Beltsville, Md., is currently working on hormones that will prevent insects from molting, or shedding their outer covering, prior to passing on to the next stage of growth, and Martin Jacobson has applied for a patent for a juvenile hormone that affects house, stable and face flies, some mosquitoes and the fire ant. Taking a different approach, Entomologist William Bowers, of the New York State Agricultural Experiment Station, has isolated two substances from ageratum, a flowering plant, that interfere with an insect's production of juvenile hormones. When these antihormones are applied to immature cotton stainers and Mexican...
PHEROMONES. Insects give off and are programmed to respond to chemical compounds called pheromones. The pheromone exuded by a female insect, for example, automatically draws males of the same species for miles around. Other pheromones identify members of a colony, trigger fight or flight reactions, or are used to mark a path toward food sources. At Beltsville, Jacobson has identified the sex pheromones of the American cockroach. Oriental fruit fly, Mediterranean fruit fly and southwestern pine tip moth. Synthetic forms of such chemicals could, if spread in large quantities over an insect-infested field, so confuse male insects that they...