Jennifer Viegas writes in Discovery News that if our flowers and vegetables are surrounded by weeds, they're less likely to be attacked by insects. By adding and removing weeds from around test plants, horticulturists Stan Finch and Rosemary Collier found that insects would investigate the weeds, find them unsuitable and often fly away, leaving the valuable plants alone.
Plant-eating bugs look for three things: plant smells that tell them when to land, visual cues that tell them where to land, and the touch and taste of the plants, which tell them if they should stay or fly away. Finch says, "To paraphrase one of the songs made popular by 'Meatloaf,' 'Two out of three ain't bad.'?[But] plant-feeding insects must get three out of three from an appropriate plant if they, and their progeny, are to survive."
Finch and Collier compared cabbages planted in bare soil with cabbages grown in fields of clover. 36% of root flies laid eggs on the bare soil cabbage, compared to only 7% on the cabbages surrounded by clover.
Horticulturist Don Mahoney says most weeds also produce small flowers that attract helpful insects, like ladybugs, that prey on damaging bugs, like aphids. He says, "I once read where weeds were described as 'Mother Nature's Red Cross.'"
Speaking of plants, what's the secret behind William Henry's mysterious Blue Apples?
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