Editorial: Learning to live with our garden pests
The evolutionary biologist JBS Haldane was reportedly asked what his long study of creation had taught him about the nature of God. “It would appear,” Haldane said, “that God has an inordinate fondness for stars and beetles.” One appears in profusion in the heavens, the other in vegetable gardens and just about everywhere else.
There are an estimated 350,000 species of beetles. Cooperative Extension Service entomologist Alan Eaton passed around clear containers holding two of them; asparagus beetles and tortoise beetles, tiny humped creatures that devour sweet potato, morning glory and other plants.
The event was billed as a chance to tour the community gardens on Clinton Street with a bug expert, but it was also a lesson in humility, since a garden is a reflection of the gardener. The whispered vow, as we walked around, was next year the garden, and the gardener, will be better.
Eaton is an expert in integrated pest management, which is another name for using every trick in the book to minimize the need to engage in chemical warfare with plant pests and pestilence. He is a delightfully geeky ham in a slouch hat whose pockets hold hand lenses and vials containing live insects. His first lesson, conducted at the roadside, was “know the enemy.” Thus the containers of insects. And know when they arrive. There’s no point in dropping bombs before the enemy forces gather.
In one garden, Eaton reached out and snatched a fuzzy, inch-long moth, a European corn borer looking for a plant on which to lay eggs that will turn into the brown caterpillars found to the cook’s disgust when the ear is shucked. The insects survive winter in the corn stalks that slothful gardeners leave standing and emerge to infect the next year’s crop. A garden should be stripped clean, the remains of its plants chopped and buried or composted and any diseased plants burned, Eaton explained. We silently vowed to be a better neighbor and as penance will not grow corn this year.
Counting just the most common pests, there are scores of insects that prey on garden plants and scores more that prey on them. A gardener must learn which is which and have, as one person put it, a “squish, don’t-squish list.” The “good” bugs include about 40 species of tiny wasps that search out the caterpillars that will host their eggs and feed their young. Eaton held up a photograph of a tomato hornworm, a green, 3-inch-long eating machine that sports a fierce looking spine. Attached to the caterpillar were the silky cocoons of dozens of wasp larvae that had eaten their way out of the caterpillar.
We think of the rhyme:
Big fleas have little fleas,
Upon their backs to bite ‘em,
And little fleas have lesser fleas,
and so, ad infinitum.
Eaton pointed to a tomato plant whose leaves already showed the wilt and faded yellow of early blight, a fungus disease that can be minimized by mulching, which prevents rain drops from catapulting the fungal spore upward. What, we think, in our garden and life has gone unmulched?
He pointed to the quack grass that surrounds each garden plot and sends its long, white roots snaking toward unclaimed land. The roots are alleopathic; a hormone in them weakens rival plants that may survive but not thrive. What, we think, is the quack grass of life? Television shows that leave viewers empty, social media that provide the facts of friends but little of the pleasure of friendship, obligations undertaken but resented?
Toward dusk all heads turned as a nighthawk harassed by a squadron of tree swallows soared overhead. Both species are sustained by some of the very insects we came to learn about, but unlike us, neither nighthawk nor swallow needs a list to know good bug from bad.