The recent warm weather brought many garden pests out in record numbers. Some gardeners were especially distressed by aphids on roses. Generally speaking, this indicates a stress situation such as poor soil, inadequate root formation, or dry roots, a common problem after a difficult winter and a stressful spring.
The first line of defense is to water deeply, then layer on 3-4 inches of compost. Use a thinner layer close to the plant’s stem or trunk, then layer most deeply at each plant’s dripline, where the active feeder roots are located.
Pests Thrive With Pesticide Use?
Aphids are astonishingly successful critters that thrive under a tremendous range of conditions, but they are generally quite easy to control in gardens maintained with natural care. Indeed, when aphids are persistent pests, the underlying cause is often pesticide use.
Ironically, when aphids are dealt with by natural means such as ladybugs, lacewings, and tiny predatory wasps, aphid populations decline faster and stay reduced longer than when chemical treatments are used. This may seem counterintuitive, and indeed, the reason is a bit complex.
Knocked Up Before They’re Born
In brief, when we use chemical sprays to reduce aphids populations, we “win” only in the extremely short term. Aphids can reproduce incredibly fast, building up immense populations in short order. This is because baby aphids hatch out pregnant and begin reproducing more pregnant female aphids immediately.
These early girls are usually wingless, but if the food supply can’t keep up with the boom in population, the next generation will be winged and capable of flying to your local rose garden. Aphids come in many colors and sizes, but all have a tube-like mouth adapted for sucking the juices from tender young plant growth. While some species favor certain families of plants, many are willing to eat a wide range of host plants.
Sprays Don’t Really Spray Away
Thus, a stressed garden can be overrun with aphids in just a few days. Knock them back with a toxic spray and a tiny handful of survivors are capable of repopulating the garden before you know it. Aphids persist most successfully in gardens where toxins are used because wide-spectrum insect killers also take out the beneficial insects that help keep aphids under control.
Unlike aphids, the beneficials take weeks or even months to build up significant colonies. If you spray a wide-spectrum insecticide every fewˇ days, you will effectively eliminate all the beneficials while only slowing down the aphids.
Lovely Little Lacewings
One of the best ways to control aphids is to release lacewings, which can be ordered from several supply companies as eggs or as live larvae. You mail in a card, then receive a package of either eggs, which take a week or so to hatch out, or living larvae, which begin eating immediately.
Ladybugs are another effective predator. These are harvested while dormant and stored cold, so they wake up ravenously thirsty and ready to reproduce. To keep them in your garden, lightly sprinkle the plants where you want the ladybugs to feast. Release them on a still, warm evening and they will quickly refresh themselves with water, then start mating.
While mature ladybugs enjoy aphids, the larvae are real champs, eating their weight in aphids daily. They look like tiny reticulated alligators, so if you find any, don’t goosh them, just leave them alone. It can take a week or two for ladybugs to clean up an aphid explosion, but you don’t have to sit on your hands while you wait.
Hose Off, Eh?
One of the easiest ways to get aphids off your plants is to hose them down. Spraying with an ordinary hose works well on early aphids, which can’t fly back to the yummy plant where you found them. Later in the season, use your thumb to intensify the spray, or invest in a Bug Blaster, a rounded hose-end fitting that creates a powerful spray that will dislodge and fatally traumatize many insect pests without harming your plants. These easy-to-use tools cost around $20 and work well on tent caterpillars too.
Off The Ants First
In some situations, you have to control ants before you can control aphids. Certain ant species harvest sweet, sticky honeydew from aphids, then protect them from beneficial insects in return. There are several good ant controls available, including sticky traps that wrap around tree trunks, and sticky cards and tape that can be wrapped around smaller plants.
Diatomaceous earth can slice an ant’s tough carapace, as can finely powdered borax, but both products take time to work. A natural care product that works extremely fast on ants is called Ant-A-Tak. Made from clove oil, wintergreen, orange oil, cater oil and paprika, it smells quite pleasant and is astonishingly effective on infestations of tiny sugar ants.
Whack La Cucaracha As Well
Ant-A-Tak also works on fire ants (the ones that make the huge hills), on cockroaches and spiders as well as other tough pests. Like any pesticide, botanicals should be used with caution; always protect your eyes and skin and avoid being hit by the direct spray.
Made of food grade materials, Ant-A-Tak is listed as safe, nontoxic, and biodegradable. However, even this natural pesticide should never be used when bees and other beneficials are present, since it can harm non-target creatures as well as the intended pests.
Here’s an online source if you can’t find it locally:
Hi all, I just learned that the charming image of the aphid on the ladybug was taken by Kathy Keatley Garvey of the UC David Department of Entomology and Nematology and want to give her full credit for it.
Hi all, I want to state that the charming image of an aphid atop a ladybug illustrating by blog for May 30, 2011, was taken by Kathy Keatley Garvey of the UC Davis Department of Entomology and Nematology.