Predator insects control plant lice

Garden Q&A

May 03, 2008|By Ellen Nibali and Jon Traunfeld

Aphids are all over the tips of my sedum, and it's getting distorted. What do I spray?

Early season aphid (plant lice) populations explode, then crash. Many predator insects, such as ladybugs, syrphid (flower) flies and even wasps, are enemies of aphids and control their numbers as the season progresses. Look for tan, puffed-up aphids. These are aphid "mummies," dead aphids that have been parasitized. Hold off the insecticides so you don't ruin this natural course of events. Your sedum will outgrow the distortion of their leaves.

I want to grow an apple tree, but I only have room for one. Would my neighbor's crabapple tree work as a pollinator for my tree? How about other fruit?

As long as it is within 100 feet and their bloom periods overlap, a crabapple tree would make an excellent pollinizer for your apple trees. Sweet cherry and pear, likewise, can be pollinized by ornamental versions. Peach, sour cherry, blackberries and raspberries are self-fruitful, so they do not need a second pollinizing variety. (They do need pollinators, i.e. bees.) Many European and Japanese plum varieties are self-fruitful, but not all are. Consult references or call us for which varieties will pollinate each other. Blueberries are technically self-fruitful, but plant more than one cultivar to get a decent yield.

Checklist

Look for plant sales sponsored by local organizations this spring.

Stay ahead of weeds now. It will pay off when they never set seed.

Ellen Nibali, a horticulture consultant, works at Maryland Cooperative Extension's Home and Garden Information Center, and Jon Traunfeld is the director of the Home and Garden Information Center. The center offers Maryland residents free gardening information. Call the center's help line at 800-342-2507 or e-mail plant and pest questions through the Send a Question feature at hgic.umd.edu.

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