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SPECIAL ISSUE: SPRING HOME & GARDEN GUIDE : Moths Very Efficient at Planting Worms on Your Tomatoes

March 05, 1989|ROBERT KNIGHT | Times Staff Writer

Most everybody who has grown tomatoes has seen those worms.

Huge, green ones with upholstered hides and a large hook at the end. The "tomato worm," which is really the tobacco hornworm, turns up uncannily in a vegetable patch just as the plants are taking off.

If a gardener isn't quick to stop them, they can eat vast quantities of buds and foliage, leaving the tomato plants looking like the skeleton of a grape bunch: a sea of tiny stumps.

The best way to halt them is simple: "You pretty much just pick them off by hand," since there are usually not many of them, says Mark Nestor of the University of California Cooperative Extension office in Anaheim. The pesticide carbaryl, marketed as Sevin, and the bacterial agent Dipel can also be used on plants to kill the worms.

But how do these little monsters even know that you are growing tomatoes?

Well, they don't. But their parents do. The worms are the pupa stage of the hornworm, which becomes the sphinx moth when it grows up. A sneaky pest, the moth sniffs out tomato plants during the night hours and deposits eggs in the soil, much like tiny time bombs waiting to emerge and decimate your crop.

"They're very efficient at finding their food source," says Nick Nisson, entomologist for the Orange County commissioner of agriculture. In a glass case in Nisson's Anaheim office is a preserved, mature sphinx moth. It is just as well that the rascals are nocturnal; these things are BIG and ugly, with 4-inch wingspans. And you thought the worms were gross.

Nisson, whose job is to identify and monitor insect species that may threaten the county's agricultural industry, takes a rather benign view of the thriving world of creepies and crawlies.

"Most things aren't worth worrying about," Nisson says. "There is an attitude that every insect you see in the garden is bad. But many are innocuous or even beneficial."

This means it is not always necessary to use pesticides when preparing your garden plot in the spring. The soil should be turned and examined for eggs or grubs, and if there are none, you are home free. At least at the start.

Ladybugs are among the good guys. They feed on aphids and other little menaces. Predacious mites also eat other bugs, as do green lacewings and even earwigs, which also help clean up garden floors by consuming old foliage.

Earwigs, which come in several varieties, the most prevalent being the European type, are about an inch long, reddish brown to brown or black and have wings under short, hard covers and a pair of pincers in the rear. The latter are quite formidable and can put a dent in a finger or toe if the insect is provoked.

How do you provoke an earwig? Well, you could start by bringing up that old European myth about them crawling into people's ears at night, which is where they got their name. An updated version of that was in an episode of Rod Serling's "Night Gallery" TV show in which the villain survives an earwig's journey through his head, ear to ear, only to find out that it was female--and laid eggs! Eyaaaahhhhhh!

For the record, earwigs are essentially harmless, other than the occasional nip. Sometimes delinquent earwigs, enraged at re-runs of old "Night Galleries," are found consuming healthy plants, but who's perfect?

Ants are also a mixed bag, according to Nisson. They help scavenge the garden floor, but "in most cases, the ants are not doing any good."

This is mainly because the little gluttons are addicted to honey dew, the sweet, sticky emissions of aphids. As for aphids, they are those tiny insects that reproduce by the thousands, leaving a light green or black living film on the leaves of such vegetables as lettuce and spinach, which kind of takes the appeal out of your average garden salad. So fond of the honey dew are the ants that they actually prevent ladybugs and other guardians of the garden from doing their job of eating the aphids. In effect, the ants "farm" the aphids, moving them to safety at times, "so indirectly, the ants are a problem," Nisson says.

Aphids can be cleaned off plants by shooting water on them with a hose, scraping them off or pelting them with a number of pesticides, according to UC Extension's Mark Nestor.

Ants can be controlled with ant stakes and by directly spraying or powdering them with any number of pesticides.

Southern California has zillions of brown snails, courtesy of the French, who should have curbed their generosity right after donating the Statue of Liberty. Actually, it was just some misguided soul who brought the snails over in the mid-19th Century to breed them for restaurant use. Some of them got away. Now their descendants are laughing at les humans, who can't seem to get them out of their yards and gardens.

But there are measures you can take, short of napalming your garden. You can harvest them, plop them into some cornmeal for 3 days to clean impurities out of their systems and then look up some good escargot recipes.

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