Healthy plants can stand up to a leafhopper invasion


August 08, 1999

Q. My lawn and flower beds have been invaded this summer by some small bugs that fly up when I touch a leaf. Many of my plants have little white dots on their leaves; otherwise, they look pretty healthy. Should I be alarmed?

A. The bugs are leafhoppers -- small, light-green, wedge-shaped insects that suck the chlorophyll from a variety of vegetable and ornamental plants. Symptoms of leafhopper damage range from small white dots (stipples) on leaf surfaces to browning and curling of leaf edges.

It sounds as if your plants are well-maintained and will be able to withstand the feeding damage. So, no need to be alarmed.

Q. My hostas are located next to our driveway and have done beautifully for years with very little care. This summer, however, they have brown splotches all over them. Shall I cut them back? Is this just the effect of hot weather?

A. Yes, hot weather is to blame. Very sunny, hot days are scorching hosta leaves in central Maryland, particularly where the plants are in a sunny, exposed location. Remove the flower stalks if the plants are blooming and cut out the brown leaves to improve the plants' appearance.

Water your hostas deeply at least once a week and next spring they'll emerge as healthy as ever.

Q. My wife had me half- persuaded to go organic this year in our little garden. Then I started losing entire tomato stems to some huge green worms with a red horn on their head. What's the strongest insecticide I can legally use to kill these monsters?

A. Hold on there! Those hungry bugs are a kind of caterpillar called hornworms, and their red horns are located on their back end, not their head. They can be controlled simply by pulling them off your plants. An insecticide spray is unnecessary.

If you want to get rid of the pests and help your garden at the same time, try this: Collect the hornworms and keep them indoors in a ventilated container stocked with a few tomato leaves. More than likely, you will begin to see little white cocoons appear on the worms' skin, a sign that they were parasitized earlier by a small, beneficial wasp. Place the hornworms back in the garden so the adult wasps can emerge. As they do, they will kill the hornworms.


1. Water tomato plants deeply and regularly to avoid cracked fruit. Each plant should receive 1 to 2 gallons of water per week.

2. Dead-head perennial and annual flowers to encourage reblooming.

3. Sow broccoli, cauliflower and cabbage seeds directly into fertile garden soil. Thin young plants(18 inches apart)and cover them with a floating row cover to prevent insect feeding.

Garden tips are provided by the Home and Garden Information Center of the Cooperative Extension Service of the University of Maryland. For additional information on these questions, or if you have questions of your own, call the center's hot line at 800-342-2507, or visit its Web site at

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