How does spider mite appear in a greenhouse? - briefly
Infested seedling stock, contaminated tools, or wind‑borne migrants bring «spider mite» into greenhouse crops, after which the pest colonizes leaf undersides under warm, humid conditions. Females deposit hundreds of unfertilized eggs, enabling rapid population growth.
How does spider mite appear in a greenhouse? - in detail
Spider mites (Tetranychidae) infiltrate greenhouse production primarily through external vectors and favorable microclimates.
Common entry routes include:
- Imported seedlings, cuttings, or transplants that harbor eggs or motile stages.
- Adjacent open‑field crops releasing airborne dispersal stages that drift into the structure.
- Contaminated tools, containers, and irrigation equipment transferred between locations.
- Personnel clothing or footwear that contacts infested plants and then enters the greenhouse.
Once inside, rapid population buildup depends on temperature, relative humidity, and host plant quality. Temperatures between 20 °C and 30 °C accelerate development, while low relative humidity (below 50 %) reduces mortality of mobile stages. Abundant, tender foliage supplied by high‑nitrogen fertilization provides ample feeding material, further promoting reproduction.
Environmental management practices can unintentionally create optimal conditions for the pest. Poor ventilation raises temperature and lowers humidity, mimicking outdoor summer conditions that favor mite proliferation. Overhead misting or excessive watering increases leaf wetness, encouraging fungal growth that competes with mites, yet may also mask early damage signs, delaying detection.
Early detection relies on visual inspection of the undersides of leaves for stippling, yellowing, and the presence of tiny moving specks. Microscopic examination reveals characteristic webbing and the distinctive oval shape of adult females. Prompt identification allows immediate implementation of control measures before infestation reaches economic thresholds.