Where do spider mites on plants come from? - briefly
Spider mites reach plants when females lay eggs on leaf surfaces, and the eggs are transported by wind, contaminated seedlings, or adjacent infested vegetation. Warm, dry environments accelerate their development and spread.
Where do spider mites on plants come from? - in detail
Spider mites originate from egg clusters deposited on the undersides of leaves, stems, or fruit. Female mites lay 20‑100 eggs over a few days, and the newly hatched larvae (protonymphs) begin feeding immediately, establishing the first generation on the host plant.
The primary pathways that introduce these arthropods into a garden or greenhouse include:
- Infested plant material – seedlings, cuttings, or mature plants purchased from nurseries often carry eggs or mobile stages.
- Wind‑driven dispersal – adult females and nymphs can be lifted by air currents and travel several meters to colonize nearby vegetation.
- Human activity – hands, clothing, and gardening tools that have contacted an infested plant act as vectors when moved to healthy hosts.
- Ventilation systems – in controlled environments, fans and exhaust ducts transport mites between rows or compartments.
- Weedy hosts – wild or ornamental weeds adjacent to crops serve as reservoirs, releasing mites onto cultivated plants during periods of favorable weather.
Environmental conditions strongly influence mite emergence and spread. Temperatures above 25 °C combined with low relative humidity accelerate development, reducing the egg‑to‑adult cycle to as little as five days. Under such conditions, population explosions occur rapidly, especially when plants experience stress from drought, nutrient deficiency, or pesticide injury.
Understanding these sources enables targeted prevention: inspect new stock before introduction, quarantine suspect plants, sanitize tools, manage weeds, and regulate greenhouse climate to avoid prolonged dry heat. By eliminating the initial entry points and limiting conducive conditions, the establishment of spider mite colonies can be effectively suppressed.