Something is making perfect inverted cones in the soil beside our house. Should we worry?
These clever funnel-shaped traps are made by antlion nymphs, also known as doodlebugs. When ants walk on the trap's dry crumbly sides, they fall into the bottom of the trap where an antlion hides, waiting to eat them. If you dig at the bottom, you'll find this brown dusty predator with its long pincher jaws, who is intercepting ants before they get into your house.
My hollyhock leaves are turning red and yellow. Is that rust?
Yes. The rust fungus also makes brown pinhead-size spots under the leaf. Infected leaves may be killed and plants weakened. Spray with a sulfur or other labeled fungicide as needed. At season's end, cut, bag and dispose of all plant parts so they don't harbor the fungus over winter. Next spring, monitor your hollyhocks closely. Pick off and destroy the first infected leaves, then spray to prevent spread.
Cicada killer wasps are active now. They are 2 inches long and resemble yellow jackets in coloration. These harmless wasps prey on cicadas and dig nests in soil. They are solitary insects but may congregate in large numbers. No controls are recommended.
Now is the time to fertilize Bermuda grass and zoysia grass with 1 pound of nitrogen per 1,000 square feet of lawn. Do not fertilize tall fescue, a cool-season grass, until fall because summer fertilization may cause undue stress.
Ellen Nibali, horticulture consultant, works at Maryland Cooperative Extension's Home and Garden Information Center, and David Clement is the regional specialist. The center offers Maryland residents free gardening information. Call the center's hot line at 800-342-2507 (8 a.m.-1 p.m. Monday-Friday) or e-mail plant and pest questions through the Send a Question feature at hgic.umd.edu.