Texas Bug Book
By Tracy Hobson Lehmann
Gardeners know aphids as tiny, squishy pests that can suck the life right out of plants and, as if that weren't enough, leave behind a sticky, nasty mess.
That's why it's surprising to hear a nursery owner embrace the soft-bodied insects. Roberta Churchin, co-owner of Shades of Green Nursery in San Antonio, appreciates their role in the good-bug, bad-bug drama that plays out among the stems and leaves.
"Aphids are a primary food source for beneficial insects," Churchin says, and those good bugs are important to controlling other insects that damage plants.
Ladybugs and their alien-looking larvae eat aphids. So do assassin bugs, which sound vicious but also chomp mosquitoes, large beetles and their grubs, according to Malcolm Beck and Howard Garrett's Texas Bug Book ($29.95 University of Texas Press). In their larval stage, lacewings - one of the prettiest insects in the garden - eat hundreds of aphids a day. The larvae, sometimes called aphid lions, also have a taste for damaging whiteflies, cabbage loopers, mealybugs and some beetles and their larvae.
Aphids get partial credit for Churchin's switch to a chemical-free nursery environment about 20 years ago. She had noticed lacewing larvae on a mandevilla stem covered with aphids and left them so they could be photographed for a TV segment. The next morning, the aphids were gone.
"We realized we didn't have to spray anymore," Churchin says. Insects, like bacteria, adapt, mutate and become resistant to sprays, she explains. "But they can't get resistant to beneficial insects."
Aphids, which feed on tender new growth, are tenacious, but they can be controlled with a strong blast from the water hose or by releasing ladybugs.
Spray the affected plant with water before releasing ladybugs; these little beetles need water. The adults will eat some aphids, but even more will be eaten by their larva.
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