Tetranychidae

Common Name

Spidermites

Overview

The family Tetranychidae consists of small arachnids known as spider mites. These mites are plant-feeding pests capable of causing significant damage to a wide array of plant species in agricultural and natural settings.

Taxonomy

Key Characteristics

  • Size: Very small, typically less than 1 mm in length.
  • Body Shape: Oval-shaped and often reddish or greenish in color.
  • Feeding: Use specialized mouthparts to pierce plant cells and consume their contents.
  • Webbing: Some species produce silk-like webbing on host plants.

Life Cycle

  1. Egg: Laid on the host plant; hatch in 3-5 days.
  2. Larva: Six-legged stage that lasts a few days.
  3. Nymph: Two stages (protonymph and deutonymph), each with eight legs and lasting a few days.
  4. Adult: Reproduces quickly, with life cycles completing in as little as a week under favorable conditions.

Behavior and Ecology

  • Prefer warm, dry conditions.
  • Can form large colonies.
  • High reproductive rate enables rapid population growth.
  • Feed primarily on the undersides of plant leaves.
  • Some species show a preference for specific host plants while others are more generalists.

Notable Species

  • Tetranychus urticae (Two-spotted spider mite): A widespread and economically significant pest.
  • Panonychus ulmi (European red mite): Common in apple orchards.
  • Oligonychus pratensis (Banks grass mite): A pest of corn and other grasses.

Conservation

Typically, control methods for spider mites focus on agricultural and horticultural practices rather than conservation since many are considered pests. Predatory mites and biological control agents are often used to manage populations.

Significance to Humans

  • Agricultural Impact: Known for damaging crops, ornamentals, and houseplants, leading to substantial economic losses.
  • Control Methods: Include chemical acaricides, integrated pest management (IPM) strategies, and biological control agents like predatory mites.

Fun Facts

  • Some spider mites can develop resistance to pesticides rapidly.
  • They may produce webbing to protect themselves from predators and environmental hazards.
  • Spider mite infestations often go unnoticed until they have caused significant damage.
  • Color changes in spider mites can occur in response to the host plant they are feeding on.
  • Spider mites can disperse over long distances by wind.