Garden Q&A: Hover flies

A tiny flying insect appears late afternoon/early evening in our neighborhood and lands on people. Could you help us identify it?

Shoo away gently. This is your friend times two. The syrphid fly, commonly known as a flower fly or hover fly, feeds on nectar and pollen, making it a good pollinator. Its bee-like color and markings protect it from predators, though it has only one set of wings (bees have two sets) and doesn’t sting. The female syrphid fly lays its eggs on a plant infested with aphids, mites or other insects. When larvae hatch, they gobble up the pests so, contrary to stereotypes, these flies are beneficial and should not be sprayed. They may occasionally land on humans, attracted by human sweat or perfume.

Our arborvitaes have been turning brown, starting inside near the trunk, over the last two weeks. What could the issue be? They were planted this year.

Reasons for browning include drought, too much moisture and planting too deeply. However, since the browning of the foliage is recent, this could be normal leaf drop. Many evergreens lose some old foliage in autumn. Usually color change and shedding is limited and occurs on the inside of the plants. Keep your new trees well watered until the ground freezes, and continue supplementing rainfall in dry weeks for another year until they are established. Make sure mulch is no thicker than 2-3 inches and away from the base of the trunk.

University of Maryland Extension’s Home and Garden Information Center offers free gardening and pest information at extension.umd.edu/hgic. Click “Ask Maryland’s Gardening Experts” to send questions and photos.

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