Spider mites
/ˈspaɪdɚ maɪts/
Definition
Spider mites are tiny plant-feeding arachnids, not insects, that pierce leaf cells and suck out contents. They usually live on leaf undersides and are often recognized by fine webbing, pale stippling, bronzing, and leaf drop on infested plants. Common in dry, warm conditions indoors or outdoors, they reproduce quickly and can damage many houseplants, vegetables, and ornamentals.
Effects on Plants
- Leaf cell damage: spider mites pierce leaf cells and remove contents, which causes fine pale speckling called stippling. As injury builds, leaves may look dull, bronzed, or scorched and can drop early.
- Dry, warm outbreaks: Populations often build faster in hot, dry conditions, especially on stressed plants and in heated indoor spaces. Dusty leaves can make infestations worse because natural enemies are less effective.
- Webbing as a late clue: Fine silk usually appears after numbers increase, often around leaf undersides, tips, and leaf axils. By the time webbing is obvious, plant stress is often already significant.
- Growth and crop impact: Heavy feeding reduces photosynthesis, the process plants use to make sugars from light. This can slow growth, weaken flowering, and lower the quality of ornamental foliage and some edible crops.
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