Q. Dear Mike: Several years ago, someone told me that ladybugs and Praying Mantis were good for the garden. Is this true? If so, please tell me where to buy them. Thanks.
- ---Dave in Chestnut Hill, PA
The spotted red 'ladybug' we all know so well (more correctly called the 'lady beetle' or 'ladybird beetle', as these insects are true beetles and not bugs) does dine on the occasional aphid and other soft-bodied pest, but like many insects, it doesn't really eat all that much in it's adult form. It's the ladybug's larvae that are voracious predators of soft-bodied problem insects, especially aphids. Gardeners plagued by those sap-sucking perfidious pests (i.e. rose growers) should become acquainted with the appearance of this beneficial ladybug baby; otherwise, they might try and kill the spiny, scary-looking, alligator/dragon-like things!
And you can buy ladybugs mail order. But its important to release them correctly or they will all fly away. Although there are hundreds of different types of ladybugs—including one that's blood red with no spots and a tiny one that's jet black—you only see the basic "Convergent Lady Beetle" (Hippodamia convergens) offered for sale to homeowners. These are collected from winter hibernation sites (and yes, it's fine to do so; this has been going on for many decades without any negative impact on their population).
When they arrive, the ladies must be released in the evening into a soaking wet garden that has some aphid problems.
Release them during the day and they will all fly away.
Release them into a dry garden and they will all fly away.
Release them into a garden with no aphids for their babies to eat and they will all fly away.
But they won't fly in the dark, so releasing them just after sunset insures they'll stay the night. They're dehydrated when they arrive, so a garden that you've made soaking wet before their release will provide many opportunities for them to quench their thirst and thus make them feel that this place has some promise. And if they encounter aphids as they're drinking and checking it out, many of the ladies will decide that this garden is a good place to spend the summer. Just be nice to those scary looking babies and don't destroy their eggs, which are yellowish-orange ovals laid on the undersides of plant leaves.
You can also attract local ladybugs—and lots of other beneficial insects—with a three-pronged method.
- Don't use chemicals of any kind in your garden! (I love saying that!)
- Provide appropriate water sources by filling saucers with pebbles and water. The tiny insects can perch on the pebbles and get a drink without fear of falling in and drowning, as they could in a big birdbath.
- Grow plants whose small flowers produce pollen and nectar that the adults can easily get to for a little sugar rush.
This plan will also bring in many other beneficials. Like the beautiful lacewing—a delicate looking flyer whose babies are very similar in appearance to ladybug larvae, but are even better at chowing down on those perpetual pests of roses and other plants; so much so that their common name is the 'aphid lion'! You'll also attract Braconid, Trichogramma and other mini wasps. So small you can barely see them, these tiny creatures ignore humans, and lay their eggs inside or on top of pest caterpillars, parasitizing and killing them and, of course, breeding more caterpillar-controlling wasps. (Those white 'spines' you often see on tomato hornworms are Braconid wasp eggs).
Lacewings and mini-wasps can also be purchased mail order with very good results. Generally shipped in the egg stage, you place the little containers in a shady protected spot in the garden. Adult wasps will emerge to do their caterpillar-controlling thing; and those aphid lion lacewing babies will hatch and go looking for aphids. (Obviously, locate their containers near the plants with those problems; remember—they need some pests to prey upon to survive!)
That water, pollen and nectar will also bring in other beneficial insects, like damsel bugs, big-eyed bugs, minute pirate bugs, assassin bugs (which attack adult Japanese beetles!) spined soldier bugs, syrphid flies (which look like bees, but hover like hummingbirds!) and tachnid flies. Go online and become familiar with the appearance of these creatures; otherwise you might try and kill your spined soldier bugs, which look a lot like stink bugs (the good guys have sharply pointed shoulders) or tachnid flies, which closely resemble houseflies (the good guys have bristles, and fly in a very un-housefly-like manner).
And what about the fabled praying mantis? These creatures are amazing, but aren't truly beneficial, because they'll eat any insect they can catch, including good ones. Now, if a few appear in your garden, let them be; they're part of the natural world, fun to watch, won't harm your plants and will kill some pests for you. But I strongly recommend against purchasing them mail order; many researchers feel that those non-native mantises will attack and kill the native species when they are released.
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Question Hello. I am well aware of the value of ladybugs as good predators. Each fall, however, they seem to all want to come inside my home. I have a sun room and at times they cover the ceiling. Could this invasion be prevented if I were to place a ladybug house in my garden?
---Ursula in Missouri
Is there anything you can do to get rid of ladybugs? My uncle has them all over his back door—and everywhere else! Thank you,
---Wanda in Delta, Pennsylvania(a small town on the Mason Dixon line)
Answer. I answer LOTS of questions this time every year about these pest eating girls—which, in most home invasion cases, are likely to be multi-colored Asian lady bugs (or Ladybird beetles, if you must be technical about it). Imported and released years ago to combat a pest they naturally dine on back home in the Orient, they were thought to have died out and been a failure.
Then they started appearing in droves again—but at private homes. In the fall, they gather on South facing walls of light colored homes for warmth, and then start looking for cracks or other ways to get inside so they can hibernate for the winter, just as they did in caves back home. It is not unusual to find hundreds—or even thousands—clustered in a high corner of an upstairs bedroom, all pressed together to conserve heat for the winter. I generally have suggested two things. One, to thank them for finding those holes in your insulation—because if they're getting in, your precious heat is getting out. ("What are we?Heating the street?!") Do some caulking or repair the weatherstripping or close the window more tightly where they entered.
Then I've been suggesting that people vacuum them up into a clean bag that contains some shredded leaves or raffia, mist it well and keep it in the fridge--misting occasionally--till Spring, and release them into the garden then. But I wondered—where and how do they overwinter if they can't break into your home? IS it safe to vac them up and put them in the fridge? Or outside? Am I/was I/have I been, Mother-May-I-correct?
And so, I seized the opportunity to get in touch with one of my favorite insect experts, former beneficial insect specialist for the Canadian government, and now private I PM Consultant Dr. Linda Gilkeson,who lives on Salt Spring Island in British Columbia.
She explains that Lady beetles of all kinds overwinter—indoors or out—in their adult stage. Some—especially the Asian ladies (which you can easily identify by the fact that almost no two look alike) like to worm their way into caves or colonials. But native species will also come into your home if they can, and all ladybugs try and find a way to creep into some kind of crack, crevice or other protected place for the winter.
Linda—excuse me—DOCTOR Linda feels that it is "really important to get them back outdoors for the winter. In the warm dry conditions indoors,they will quickly use up their body reserves needed for the winter and will die in droves. They are quite tough and can be swept up or vacuumed with a small hand-held vac, and carried outdoors, where the cold keeps their metabolism slow until spring."
I asked her what she thought of my advice to keep them lightly mistedin the fridge till Spring. She says it COULD work, but "only if they end up in a household of dedicated lady beetle-o-philes who would put their welfare foremost until spring. If someone slips up and they are allowed to dry out, they will die." Most refrigerators, she adds, "keep the air dry as part of the defrosting function," and she feels it might not be realistic to expect people to remember to provide moisture without fail all winter. And the reverse is just as bad: Too wet, she explains, and they could die of a fungal disease—especially when they're all crowded together like they tend to do.
There is, however, a third option. If, like me, you bring a lot of plants indoors for the winter, and if, like me, you maybe might not get every single little aphid off (hey—I was busy, OK? What are you—acop?!), you can try and carefully re-room some captured ladies to do alittle aphid eating for you.
Wait till its dark out and mist the plants down really well. Turn off ALL the lights in the room and then spread the ladies out on the wet,infested plants. They won't fly away in the dark, and they're very thirsty. Hopefully they'll scour the plants for that water, encounter aphids, and do what comes natural. Bad for the aphids, good for your plants. Keep the room as dark as possible for as long as possible—they will cluster around lights. So if you can, screen off entrances to light fixtures—and tape over electrical outlets.
Linda warns that she "worked in a solar greenhouse where we released lady beetles to control aphids. The greenhouse became quite cool in the winter, and when fall came, the beetles disappeared into the woodwork(literally) and, most inconveniently, into the electrical outlets, so we couldn't plug anything in all winter without crushing beetles."
And those houses I've always assumed were as worthless as the ones for butterflies? "They can be cute garden ornaments", she says, "but they're no more attractive to a lady beetle than any other painted piece of hollow wood. Beetles overwinter in leafy, mulchy areas,rockery, outbuildings…I personally cut my corn stalks down and lay them on one of my garden beds—you'd be surprised how many lady beetles go in there for the winter.
Although the multi-coloured Asian ones do seem to be looking for structures that remind them of rocky outcroppings," she concludes,"native species enjoy overwintering in the hollow centres of plant material like corn stalks and bamboo stakes."
You Bet Your Garden Question of the Week ©2005 Mike McGrath.