Good Bugs in the Greenhouse

I was mid-way through a shower the other morning when I realized I wasn't alone. (Not to worry. This is a family-friendly blog. Please read on.)

My showering companion that day was one of the best friends a gardener can have. It was elegant.... a beautiful pale green, with veined wings and tiny bulging eyes that don't miss a trick. If you guessed "green lacewing," you're right.

Green lacewings are a welcome and common sight in environmentally-friendly Colorado gardens in warm weather. But where did this guest come from in the middle of winter? It took me a few minutes, then I figured it out. Kris, Tagawa's co-director of annuals, had issued a personal invitation. Here's how.

Kris is an organic gardener at home, and is always interested in finding new ways to grow and garden organically at Tagawa's, too. Last October, she began what I like to call "Tagawa's Great Lacewing Experiment." And so far, that experiment is a resounding success! The adult green lacewing sharing my shower the other morning was testimony to that success. It had apparently hitched a ride home with me on one of Tagawa's poinsettias.

Last fall, Kris turned loose about 5,000 live lacewing larva, the voracious bug-eating stage of the insect that emerges when the lacewing eggs hatch. Not long afterward, Kris brought in small cards about the size of a bookmark that were coated with lacewing eggs embedded in lacewing food. In the warmth and humidity of the Tagawa greenhouse, the eggs hatched out quickly. These new larvae didn't have to go far for their first meal since Kris had strategically placed the cards throughout the houseplant department where insect pests can be a challenge this time of year.

Once the larvae morph into adults, Kris supplements their diet with a special mixture of honey, bee pollen and brewer's yeast brushed onto cards suspended throughout the houseplant department. Lacewing larvae will eat 200 insect pests a week, which is why gardners love them. But the adult lacewings aren't eating machines like the larvae, so they thrive on the extra food that Kris gives them. It was one of these well-fed adults that came home with me.

But why does Tagawa's need insect control in the greenhouse? That's easy. Any "healthy" greenhouse, like any "healthy" landscape, will have its fair share of insects. The goal is not to have zero insects. The goal is to keep insects in check... or more specifically, to help Mother Nature keep them in check, to a point where damage is insignificant. And that's exactly what Kris' lacewings are doing.

She says the results were "immediate." Within days of introducing the lacewings, Kris says the number of mealy bugs, aphids, thrips and spidermites on the houseplants plumeted. Kris estimates that the level of "bad" bugs dropped by eighty percent without an ounce of chemical insecticide being used. In fact, with the green lacewings on duty, using potent insecticides in the greenhouse is prohibited. Some soaps and botanical oils can be used without harming the "good bugs."

This speaks to one of the big problems gardners create when they "spray for bugs." Strong chemical insecticides kill the damaging bugs and the beneficials. And since the "bad" bugs tend to reproduce more quickly and more prolifically than the "good" bugs, it's the bad bugs that get the upper hand. The gardeners, and Mother Nature's balance, have a hard time catching up.

Is Kris likely to increase her cast of beneficial characters as spring approaches? Indeed she is. She's looking at a wonderful little critter called a "mealy bug destroyer." Guess what they eat.

Inviting beneficial insects into the greenhouse is in keeping with Tagawa's commitment to sustainability, and to a leadership role in the green industry. Tagawa's was the first Veriflora Certified Sustainable garden center in the country. Sustainability and earth-friendly gardening practices are a priority for Tagawa's. We invite you to wander through our houseplant department and see if you can spot one of Kris' lacewing "launching pads" suspended over the plants. They're pretty interesting.

And what about the little green guest I found sharing my shower? I tucked it into a small plastic tub, gave it a tissue for something to hang onto during the ride, and released it in the middle of Tagawa's houseplant department. It took the elegant little bug all of half-a-second to take off and fly up into the greenery. Here's hoping its offspring will be chowing down on the pesky bugs any day now.

Lovin' the Ladybugs

Gardeners all along the front range are talking about this summer's friendly invasion of ladybugs. I started noticing them on my "volunteer" crop of sunflowers about a month ago. Their numbers have been climbing eversince, and I love to see it!

Whitney Cranshaw, one of the top bug gurus at Colorado State University, says we have our wet spring to thank. All the rain triggered a lot of lush, green growth on our plants. There's nothing aphids love more than tender, succulent leaves and buds. And there's nothing ladybugs love more than aphids. It's all part of the balance that Mother Nature tries to provide when we humans don't get in the way with lots of chemicals, that take out both good bugs and bad.

Quite rightly, children are taught to love and protect ladybugs, also known as "lady beetles." They delight in finding the bright round ladybugs on plants, and recite short poems urging them to "fly away home" to their own children. Maybe it has something to do with the polka dots. Many of the more than seventy varieties of lady beetles in Colorado come with two or more distinct black polka dots on their shiney red body. Polka dots just seem a friendly sort of decoration.

But while we jump to the defense of adult lady beetles, a lot of gardeners would take one look at a ladybug pupa or larva and reach for the insecticide. The early stages of ladybugs look nothing like the charming adults.

Ladybug larva, especially, often look like the voracious predators that they are: very tiny lizard-like creatures with bowed legs and little spiney projections up and down their back. Think of the larva of any insect as its "teenaged" stage. You just can't fill 'em up, which in this case is good. In addition to chowing down on aphids, the different types of lady beetles in Colorado (both larva and adults) thrive on eating mealey bugs, insect eggs, spider mites and scale.

It's well worth getting to know a gardening ally like this in all of its stages and "outfits." Link to the CSU fact sheet on lady beetles and get to know the appearance and habits of these wonderful little insects. http://www.ext.colostate.edu/pubs/insect/05594.html Get the kids involved, too. They're never too young to learn the notion of balance in the natural world.

As long as the aphid population along the Front Range stays high, the number of ladybugs dining on them is likely to do the same. But when the food source starts to decline, the ladybugs will fly off in search of a new banquet. In the meantime, we should take delight and satisfaction in knowing that there's an army of aphid-eating insects right in our own back yard, and do everything we can to make them feel welcome. Hopefully, they'll take the hint, and come back next year.