How does spider mite look in a greenhouse? - briefly
In greenhouse environments, spider mites are extremely small (0.3–0.5 mm), translucent to pale yellow‑green, often reddening on heavily colonized leaves. They congregate on the lower leaf surface, producing fine silken webs and a stippled, yellow‑white damage pattern.
How does spider mite look in a greenhouse? - in detail
Spider mites in a greenhouse are tiny arthropods, typically 0.2–0.5 mm long. Their bodies are flattened, oval, and covered with a waxy coating that gives a pale green, yellow, or reddish hue depending on species and plant diet. The legs are long and thread‑like, allowing rapid movement across leaf surfaces.
Key visual indicators include:
- Webbing: Fine, silvery‑white strands that drape over the undersides of leaves, especially near leaf veins and petioles.
- Feeding damage: Small, stippled spots where chlorophyll has been extracted, forming a mosaic pattern that may coalesce into larger yellow or bronze patches.
- Eggs: Spherical, translucent to pale yellow, often deposited in clusters on the lower leaf surface or within the web.
- Larvae and nymphs: Six‑legged first‑instar larvae appear lighter and more translucent than adults; subsequent nymphal stages develop eight legs and acquire the adult coloration.
- Population density: Heavy infestations create a dense carpet of mites, visible only under magnification, but the cumulative web and damage become obvious to the naked eye.
Environmental conditions in greenhouse production—high humidity, warm temperatures (20–30 °C), and abundant foliage—promote rapid mite reproduction. Consequently, the visual signs may appear within a few days of initial colonization, progressing from isolated stippling to extensive leaf bronzing and widespread webbing if unchecked.