Spring Gardening Guide

Insects and the Garden: a Complicated Relationship

There are good bugs, and there are bad bugs. Here’s the wisdom to know the difference.

By Chris Abshire February 8, 2015 Published in the February 2015 issue of Houstonia Magazine

Just as there’s plenty of good bacteria residing in our digestive system, there are many, many good bugs in the garden. You probably see them every day without realizing what a boon they are to your beds and bushes: dragonflies, spiders, milkweed assassin bugs—and rough stink bugs too—all keep watch over your garden, snapping up pests with a precision that no insecticide can match. Ladybugs, meanwhile, may be the most underrated of gardeners’ friends. They’re voracious aphid eaters and love to feast on chilli thrips. 

Wait, what? Chilli thrips, also known as the Houston gardener’s current bête noire. These pests made their way over from Florida during the last decade and have begun making quick work of tomato plants and roses, typically feeding off pollen and buds until the plants’ leaves are discolored and pale. Thrips love destroying citrus trees too, and are ultra-resilient despite the ladybugs’ best efforts. In cases of mass infestation, insecticides are appropriate, although experts recommend new-generation sprays that are targeted to a specific pest—spinosad or imidacloprid in this case—and avoiding broad-spectrum chemicals that often do more harm than good.

That said, in recent years urban gardening has shifted away from sprays and toward balance through nature’s own work. “These chemicals, they’re totally unnecessary, toxic, detrimental to the environment, and horrible for the food you eat,” says Laurel Smith of Houston Urban Gardeners. She recommends far simpler and cost-effective methods, like throwing away infected plants, blasting pests with a hose, or just allowing nature to take its course. 

Don’t forget about those “organic” pesticide options, either. They range and vary by which pest you’re aiming to eliminate, but some tried and true options include a garlic spray, consisting of garlic bulbs, onions, cayenne pepper, and water, or a mix of Himalayan sea salt and warm water. These options don’t have the harmful chemicals while still making your garden less attractive to pests. But remember, too, that “if there’s an infestation somewhere, nearby there’s a bug that wants to eat those bugs. The rescuers are coming.”

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