Relationships between Insecticides, Landscapes and habitat:

Landscape Change Leads to Increased Insecticide Use in U.S. Midwest
Recently a study was published online in the Proceedings of the National Academy of Sciences linking the increased use of insecticides to landscape simplification. Replacing natural habitat with crop land causes an increase in crop pest problems. The continued growth of cropland and loss of natural habitat have increasingly simplified agricultural landscapes in the U.S. Midwest. The cause of pest increases is brought on as the removal of natural habitats destroys the habitat for the beneficial predatory insects. Creating more cropland creates a larger target area for pests giving them what they need to survive and multiply. According to Tim Meehan, the leading author of Proceedings of the National Academy of Sciences, counties with less natural habitat have higher rates of insecticidal use than counties with more areas of natural habitat. It was noted that perennial crops provide a year round habitat for insects, birds and other animals, which are beneficial to the area.
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Simplified landscapes, with lots of cropland and little natural habitat,
promote crop pest problems and increased use of insecticides.
(Credit: Illustration courtesy of Tim Meehan, UW-Madsion)
Fewer Aphids in Organic Crop Fields, Study Finds
According to the results in a study done by the Department of Animal Ecology & Tropical Biology, conventional triticale fields treated with insecticides to kill off aphids does not show any improvement and produces a bigger problem as aphid numbers increase. The problem is when fields are treated with insecticides it not only kills off the aphids but it also kills their natural enemies. They compared this to an organic crop field where they discovered three times the amount of natural enemies and five times fewer aphids.
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By Carol Staats