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Any avid gardener is well-acquainted with aphids. These tiny insects are notorious for causing yellow and distorted leaves and stunted growth in plants. In addition, they can be quite difficult to eliminate from your garden and houseplants. In this article, we provide some information on aphids to help you effectively deal with any infestations you may have in your garden.
What Are Aphids?
Aphids form part of the superfamily Aphidoidae. They are small sap-sucking insects that originated around 100 million years ago during the Late Cretaceous period. Roughly 4,000 aphid species have been recorded, of which around 250 are harmful to plants and crops. Although some aphids in your garden won’t cause much harm, large colonies can become quite destructive.
Aphids have a global distribution but tend to do better in temperate rather than tropical climates. Some species, such as the green peach aphid, feed on a variety of plants. In contrast, other species, such as the cabbage aphid, melon aphid, and rosy apple aphid, focus on just one or a few plants. All aphids produce honeydew, which is a sticky and sugary liquid excretion.
What Do Aphids Look Like?
Aphids are so tiny that they can be difficult to spot with the naked eye. They typically measure under 1/4-inch long and have soft, teardrop-shaped bodies. Their range of colors varies greatly, even within one species, and includes green, blue, black, brown, and even pink. There are also woolly aphids, which cover themselves in a waxy, white covering that looks like small pieces of cotton wool. Despite their white appearance, these aphids are actually blue or green.
Aphids have small eyes, long antennae, and three pairs of long thin legs. To suck the sap from plants, they use needle-like mouthparts, which are enclosed in a sheath called a rostrum. These insects also have a pair of cornicles, which are protruding abdominal tubes through which they excrete a defensive fluid. Although most adults are wingless, many species produce winged individuals when populations become overcrowded. The ability to fly allows them to travel to other plants and start new colonies where there is ample food.
Common Habits of Aphids
Due to the fact that wingless females are able to give birth without having to mate, aphids reproduce prolifically. What’s more, such females produce live female nymphs that are born already carrying embryos themselves. This asexual reproduction process takes place multiple times during the summer, resulting in multiple generations. It is only when autumn comes that aphids mate and the females lay eggs, which hatch into winged or wingless females when spring comes. However, aphids that live in warmer environments, such as the tropics, can reproduce without mating for many years.
Some ant species feed on the honeydew that aphids excrete. In fact, they encourage the aphids to produce more honeydew by stroking them with their antennae. In return, the ants protect the aphids on the plants where they’re feeding. This is quite helpful to aphids, as they’re quite vulnerable to attacks from predators, such as predatory ladybirds, parasitic wasps, and birds. The diet of a bird such as the American goldfinch, for instance, consists mostly of aphids. Aphids can also be infected by certain types of fungi. Their microscopic spores penetrate the aphid’s skin and kill them within three days.
Are Aphids a Threat to Humans?
Although large infestations of aphids have been reported to trigger allergic inhalant reactions in some people, these insects generally pose no threat to humans. It’s largely due to the damage that aphids do to cultivated plants, especially in temperate areas, that they’re regarded as pests. Farmers, for instance, dislike aphids, as their presence often leads to malformed fruit.
Apart from the discoloration and distortion of leaves, flowers, and fruit that aphids cause, a fungus, called sooty mold, grows on the honeydew that these insects leave behind. This mold covers the leaves and branches of plants in a black sooty substance. In addition, aphids are also prolific vectors of plant viruses. They carry viruses from one plant to another through their mouthparts.
How to Control Aphids
If you notice drying, discoloration, stunted growth, or sooty mold in your garden, chances are that you’re dealing with aphids. Getting rid of these insects, however, is not an easy task. This is due to the fact that they reproduce so successfully, and also tend to live on the underside of leaves, which you can easily miss when spraying with insecticides. If you miss even a small area, aphids can recover their population very quickly. In addition, some species are also resistant to common insecticides.
If you’re trying to control an aphid infestation, there are many different ways to go about it. One of the most effective methods is to attract their natural predators, such as ladybugs and lacewings. Flowering plants like marigolds, sweet asylum, cosmos, and dandelions will provide an environment where these predators can thrive. You can also introduce plants in your garden that repel aphids, such as catnip, garlic, and chives.
Another effective method is to spray plants that are infected with neem oil or organic insecticidal soap sprays. These agents coat the bodies of aphids, which ultimately smothers and kills them. Don’t forget to spray underneath the leaves of plants, as this is where aphids like to set up their colonies. Dusting your plants with diatomaceous earth has also proven to be effective in eliminating aphids. This earth consists of finely powdered shells, which slice up the soft bodies of aphids as they crawl over it.
If you find, though, that all your efforts to control the aphid infestation in your garden are failing, it may be time to call in a professional pest control service. A company such as Bulwark Exterminating will provide you with professional advice and an effective and long-term solution.