Tomatoes may have died from too much water

BACKYARD Q&A

August 15, 1999

Q. Help! I watered my tomato plants with a sprinkler every day and babied them in every way. But the bottom leaves of all my plants turned yellow, then brown and then dried up. I'm deeply distressed. What could have happened?

A. You may have killed your tomatoes with kindness. If your soil is saturated with water from excessive irrigation, the tomato plant roots may be deprived of oxygen. Lack of oxygen causes wilting and leaf yellowing.

On the other hand, your plants' lower leaves may be infected with early blight, a common soil-borne fungus that splashes onto lower leaves during watering. If so, you'll notice irregularly shaped, brown lesions with concentric rings. These grow in size, coalesce and kill leaves.

Stop the overhead watering; water only around the base of your plants. Cover the ground around your plants with a thick organic mulch and, if necessary, apply a copper fungicide according to label directions.

Q. My cleome are covered with some very colorful black and orange bugs. They don't eat the leaves but my plants are looking half-dead. Is there anything I can spray to kill the bugs?

A. Your problem is harlequin bugs. They are attracted to cleome and all members of the broccoli family. The harlequin is a true bug and thus has sucking mouthparts that leave foliage looking bleached out and tattered.

Spraying your plants with an insecticide in hot weather will further damage the foliage. Instead, sweep the bugs into a container of soapy water and discard them.

Q. I have five azalea bushes in front of my house that look terrible. The leaves are small and brown along the edge. I'm giving them extra fertilizer to keep them healthy. Is it just the dry weather that's making them grow poorly?

A. Yes, but the extra fertilizer isn't helping. The symptoms you describe are caused largely by the drought. Azaleas have shallow root systems and need to be watered frequently. Fertilizing them during hot, dry conditions can pull moisture out of the roots and further damage your plants.

The best thing you can do for your plants is to get a soil test this fall and amend your soil according to the recommendations you receive.

THIS WEEK'S CHECKLIST

1. Use loping shears to prune tomato vines growing over the tops of stakes. The pruning will not diminish your harvest.

2. Kill poison ivy plants by spraying with a nonselective herbicide. Poison ivy vines also can be cut and removed (carefully). Wear gloves, pants and long-sleeve shirts when working around poison ivy.

3. Add water to your compost pile during dry weather to keep the ingredients moist.

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 www.agnr.umd.edu/users/hgic.

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