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July 30, 2026Short & citedBlog
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Field Notes • Entomology

Aphid

Aphids are a large group of small, soft-bodied, sap-sucking insects in the superfamily Aphidoidea, commonly called plant lice.

Updated July 30, 20261 min readCited sources

Aphids are small, soft-bodied insects that suck sap from plants, often causing damage in gardens and farms. They are widespread worldwide and include more than 4,000 known species.

What it is

Aphids belong to the superfamily Aphidoidea and are also called plant lice, greenfly, or blackfly. They are tiny, pear-shaped insects with long antennae and a pair of tubelike projections called cornicles on the abdomen. Common colours include green, black, yellow, pink, brown, and white.

Why it matters

Aphids are significant pests because they weaken plants by removing sap, distort leaves and stems, and can transmit plant viruses. They also excrete honeydew, which encourages sooty mold growth and reduces crop yields. In Canada, they are frequent in gardens, greenhouses, and crops.

Key details

Aphid life cycles can involve both asexual and sexual reproduction, sometimes alternating between different host plants. They are most diverse in temperate regions, and their feeding often targets actively growing plant tissue. Control methods include natural predators like ladybugs and insecticidal soaps.

In short

  • Aphids are sap-sucking insects that can stunt plant growth and spread viruses.
  • They have a pear-shaped body and two cornicles near the rear.
  • Over 4,000 species exist worldwide, many in temperate areas.
  • Common in Canadian gardens and crops, they are managed with natural predators or sprays.
Canadian angle

Aphids are common pests in Canadian gardens, greenhouses, nurseries, and crops, and Canadian extension resources describe them as frequent insects on many plants.[16][17]

Quick questions

What do aphids look like?
They are tiny, pear-shaped insects with long antennae, sucking mouthparts, and often two cornicles on the abdomen. Colours vary widely.
Why are aphids considered pests?
They weaken plants by removing sap, distort growth, spread viruses, and leave honeydew that leads to sooty mold.
Where are aphids found?
They are found on many plants worldwide, especially on leaves, stems, flowers, and sometimes roots.

Sources

  1. Encyclopaedia Britannicahttps://www.britannica.com/animal/aphid
    Supports: General definition, morphology, cornicles, and pest effects.
  2. Royal Horticultural Societyhttps://www.rhs.org.uk/biodiversity/aphids
    Supports: Common names, taxonomy, size range, colour variation, and feeding habits.
  3. University of Minnesota Extensionhttps://www.extension.umn.edu/yard-and-garden-insects/aphids
    Supports: Identification, symptoms, and management context; size, colours, and cornicles.
  4. University of New Hampshire Extensionhttps://extension.unh.edu/resource/aphids-fact-sheet
    Supports: Sap feeding, virus transmission, honeydew, and sooty mold impacts.
  5. University of Florida IFAShttps://mrec.ifas.ufl.edu/lsolab/aphids/
    Supports: Global species count and pest importance.
  6. ScienceDirect Topicshttps://www.sciencedirect.com/topics/agricultural-and-biological-sciences/aphidiidae
    Supports: Species count, life-cycle complexity, reproduction, host alternation, and distribution context.