How do plants become infected by spider mites? - briefly
Spider mites reach a plant by crawling onto its leaves and using piercing‑sucking mouthparts to extract cell contents, injecting saliva that damages tissue. Their high reproductive rate and wind‑driven dispersal enable rapid population buildup and spread across vegetation.
How do plants become infected by spider mites? - in detail
Spider mites are tiny arthropods that survive on the surface of foliage. Adult females lay eggs on the leaf underside, where humidity and temperature favor development. The life cycle proceeds through egg, larva, protonymph and adult stages, each lasting from a few days to a week depending on environmental conditions. Rapid reproduction creates high population densities that can overwhelm a plant quickly.
Plants become colonized through several mechanisms:
- Host location: Mites detect volatile organic compounds released by stressed or densely leafed plants. Visual cues such as leaf color and surface texture also guide them.
- Attachment: The first contact occurs on the abaxial leaf surface. Mites use specialized claws and suction pads to cling to the epidermis.
- Feeding: Piercing‑sucking mouthparts penetrate epidermal cells and withdraw cell contents. This removes chlorophyll, disrupts photosynthesis, and produces stippling or bronzing symptoms.
- Population expansion: After feeding, females move to adjacent leaves or stems, laying new eggs. Wind, air currents, and human activities (e.g., pruning, transport of infested plant material) facilitate dispersal over short and long distances.
- Environmental influence: Warm, dry conditions accelerate development and increase reproductive rates, while high humidity slows activity. Indoor climates with controlled temperature often provide optimal habitats for mite proliferation.
The infection process is reinforced by the mite’s ability to evade plant defenses. Saliva contains enzymes that suppress localized immune responses, allowing continued feeding. Repeated feeding sites accumulate damage, leading to leaf discoloration, reduced vigor, and, in severe cases, plant death.
Effective management requires interrupting each step: monitoring volatile cues, reducing favorable microclimates, limiting movement of infested material, and employing biological agents or miticides that target vulnerable life stages.