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Local gardeners learn to identify plant problems

By Curt Yeomans

cyeomans@news-daily.com

The setting lacked the technology, fluorescent lights and theme song by The Who that are common on a “CSI” television show, but 15 local gardening enthusiasts learned Thursday how to become horticulture crime-scene investigators at the Clayton County International Park VIP Complex.

Clayton County Master Gardeners Vice-President Elizabeth Davidson taught the gardeners that a yellow spot on the leaf of a plant means an Aphid bug has been sucking nutrients out of the plant in that particular spot. They also learned from her that a hole in the leaf marks where a caterpillar munched on the foliage, and that a completely dead yard signifies overuse of pesticides and insecticides.

By the end of the 45-minute class, the gardeners had learned how to examine a dead, or dying plant, and determine the culprit behind its demise.

“That’s part of IPM [Integrated Pest Management],” Davidson said. “You’re going to go out, and you’re going to observe for your change [in the plants]. Then you’re going to come in and look at what the damage is, if there is a change in the plant, and you’re going to try to decide what caused the damage. It could be anything, from a pest, or it could be herbicide damage, or sun damage, or too much watering ...

“Once you’ve decided what the problem is, then you evaluate how you’re going to treat it.”

Davidson said there are several different types of insects prevalent locally that people have to look out for because they can cause damage to plants and yards. Common insects in this area, she said, include aphids, mealybugs, scales, mites, whiteflies, fall webworms and caterpillars.

The caterpillars, in particular, are pests that local residents need to begin looking out for since they will eat the leaves on plants, the master gardener said.

“We’re fixing to see caterpillars hit really hard,” Davidson said. “The best thing to do is, when you see the webbing, to go ahead and prune that out, and smash all the caterpillars ... It [showing up in the late summer/fall] is just part of their developmental cycle. Depending on if its a moth or a butterfly [caterpillar], they will lay the larva, the larva hatches, and becomes the caterpillar, and they are going to start feeding.”

Once problems begin to show up in plants, however, it becomes time for gardeners to channel their inner David Caruso by throwing on a pair of sunglasses while yelling out “YEAAAAAAAH!!!” or crooning “Whoooo are you? Who? Who? Who? Who?” OK, maybe the yelling and crooning parts only take place in the gardener’s head, if they happen at all, but it becomes time for the detective work and crime fighting nonetheless.

“If you can keep your aphid problem [for example] under control,” Davidson said. “Then just keep monitoring, and observing your situation, and use a pesticide, or insecticidal soap, or other means, only as necessary.”

Davidson recommended participants in her class try to use natural forms of pest control, such as introducing lady bugs into the garden since they eat aphids, before trying to bring in a pesticide. She told class participants, however, to avoid introducing an Asian lady bug into a garden because it will eat the aphids and then kill the plants as well.

When warning her students about using pesticides, she used an example of a Georgia man who sprayed a weed killer into a tree, to kill poison ivy that was growing on it, but ended up killing the grass in his entire yard instead.

She said the man learned the error of his ways when he contacted his local University of Georgia Extension Service agent, to find out why the grass died.

“The agent asked him ‘What were the weather conditions on the day you did your spraying,’ and he said ‘Well, it was very windy ...,’ ” Davidson said. “The agent then told him that was his problem. Think about it. What goes up [when being sprayed into a tree], must come down somewhere.”

Several participants in Davidson’s class said they came away with a better understanding of how to handle pest problems in their own gardens. Stockbridge resident Virginia Stephens said she once had problems with scales in her gardenia garden, when she lived in Jonesboro, and wished she had known then what she learned Thursday. She said the scales heavily damaged her gardenias, ultimately causing her to lose them.

“If I had taken this class before I planted my flowers, then I think I would have been able to save them by preventing them from getting attacked by the scales in the first place,” Stephens said.

Riverdale resident Ancel Fabre Lawrence said she has battled beetles and slugs, among other pests, in her garden. She added that she was interested in trying some of the natural pest-fighting techniques that Davidson suggested, such as introducing certain types of plant-friendly bugs into a garden, to fight off the ones that attack and kill foliage.

“I’m especially interested in trying to get more lady bugs in my garden,” Lawrence said. “It’s helpful because it gets you to think less of using pesticides.”