What are aphids?

Aphids are one of the most common plant pests. They multiply quickly and can cause significant damage to your plants. Initially, they can be hard to detect, and you usually won’t spot them until their numbers have increased and they are covering large parts of the plant. Fortunately, they are relatively easy to treat.

Symptoms

• White sheds on and around your plants. These are their shed skins and are often mistaken for other pests or even spiders

• Stems and new growth covered with tiny bugs

• Sticky surfaces on and around your plant- honeydew

• Leaves become misshapen, curled or yellowing

• Black sooty mold

• On outdoor plants - Ants can be seen on plants infested with mealybugs, aphids, white flies or scale insects

What to do now

• Isolate the affected plant.

• Fight mechanically by removing all visible bugs.

• Clean windows and surfaces around where the plant has been placed

• Treat your plant

• Use soapy water, neem oil, a store bought pesticide or insecticidal soap.

• Repeat treating your plant about once or twice a week as long as needed.

• Consider using biological pest control. Biological control can help to reduce an infestation but should be used in combination with other treatments for the best effect.

• Aphids respond well to a number of different methods, including natural predators such as lacewings and ladybugs.

• Dusting your plants with diatomaceous earth can help keep aphid infestations down. An effective preventive treatment on e.g. your edible plants or outdoor container plants that are extra susceptible to aphids.

Common questions

What do they look like?

They are tiny soft-bodied, pear shaped insects - Around ¼ in. or less (1 to 7mm), depending on the species and the age of the bug. They can vary in color ranging from almost clear, yellow, green, red, brown, black and orange. Some do also have patterns or are mottled in color. Most of the aphids you'll see are wingless but they can also produce wings.

Can they fly?

The majority of aphids do not have wings. But after several generations, when the plant becomes overcrowded or if the food supply becomes short, winged females (alates) are produced. They can then fly over to new host plants and start new colonies of aphids.

What do they eat?

Aphids feed on plant sap, and are usually concentrated on new growth, buds, fruit and soft stems. This can cause the plant to become weak and can also lead to the spread of plant viruses.

Why do leaves become sticky?

Aphids secrete honeydew which is a sticky sap. The honeydew itself is not harmful to your plants at all, but it can start to grow sooty mold on top of the leaves covered in honeydew. The sooty mold only decomposes the sap and doesn't penetrate the leaves. The mold can begin to block out light and makes photosynthesis less efficient for the plant.

Honeydew can also attract ants on outdoor plants, which feed on the honeydew. These, in turn, protect the aphids from predators

Are some plants more at risk than others?

Aphids can infest most types of plants but some are more attractive than others. Soft-leaved species can be somewhat more susceptible than hard-leaved species but you shouldn't rule out examining any of your plants.

Can beneficial insects be harmed by pesticides?

Note that these beneficial insects will also be harmed by any pesticides used on the plant. Introduce them once you’ve completed the initial weekly treatments or when you believe the aphids are mostly gone from the plant .

How do I mechanically remove bugs?

You can squash the aphids or Shower your plant with a jet of water to dislodge most of the aphids.

Can you tell me more about pest treatment?

Certainly! Some plants can react badly to pesticides or soaps so test it on a smaller area of the plant first. Always avoid direct sunlight after application as it can burn the plant. Since aphids are easy to treat, follow the principle of using the mildest alternative first.

Can I prevent this in the future?

Examine all new plants before you bring them home and consider keeping them in quarantine for the first couple of weeks. Continue checking all your plants regularly to catch any infestation early.