August 6, 2008 > Pat Kite's Garden: Aphid attack
Pat Kite's Garden: Aphid attack
Do you have aphids? This year, I don't. My daughter does. Aphids have colonized a tree. Aphid waste product is a sweet, sticky substance called "honeydew." It drips onto her lawn. It attracts a vast horde of wasps. "What do I do?" she asks. Well, it's a big tree, too tall for homeowner-safe insecticide treatment. She can call a certified arborist and get advice or she can wait until the weather gets cold and the aphids will snore until spring.
There are more than 800 aphid species or types. They may be green, white, red, pink, purple, black, blue, brown or yellow. Aphids usually have pear-shaped, soft bodies, from 1/16 of an inch long. Slow-moving aphids are wingless, but at certain times they may show up with wings. The winged versions let them take off to other plants. You seldom see just one aphid. Most are females who give birth to live young without mating. Each female can produce 100 eggs. The hatching young are ready to reproduce in about a week. This equals a plethora of aphids. Aphids feed by inserting a needlelike beak composed of four "stylets" (like sharp straws) into stems and leaves that suck out plant sap. Plant sap is the life force of plants which is why a mass attack leaves greenery and fruit looking rather sad; yellow and sometimes curled. Adding insult to injury, with heavy infestations an unsightly blackish sooty mold fungus starts living on the sweet sticky honeydew. You may notice this on fruit.
Here's what to do. Even if you don't use insecticides, natural aphid enemies live in your garden. Natural enemies include ladybugs, hoverfly larvae, green lacewing larvae, spiders, birds, hover flies, ground beetles and parasitic wasps. Some gardeners recommend spraying infested plants with a strong garden hose spray. If you water spray, do so repeatedly over several days, making sure leaf undersides get their share. A caution: while this removes aphids, it does not kill them. Spraying may spread aphids to nearby plants, where they will also multiply vigorously. There are, of course, insecticides. If you select this alternative, read the label for listed plants and use as directed. Another alternative is insecticidal soap repeated every three to five days for two weeks. This method only destroys the aphids it directly hits, and aphids are great ones for hiding in crevices and leaf undersides.
You can also buy yellow sticky traps which attract and trap aphids. On occasion I've put these among my tree roses. Planting "trap crops" like Nasturtiums - aphid favorites - especially late in the growing season attracts aphids then you destroy the Nasturtiums. In the past, I've tried all kinds of remedies. I find the best solution is keeping plants healthy, encouraging ladybugs, and patience. Aphids do go away in winter. Of course they leave their aphid eggs behind, but at least they go away for a while. In gardening, every little respite helps.