How can the presence of a spider mite be determined? - briefly
Inspect leaves for fine webbing, stippled discoloration, and tiny moving specks on the undersides; confirm with a hand lens or microscope to view the eight‑legged mites or their eggs. Differentiate spider mites from other pests by their characteristic size (0.3–0.5 mm) and the presence of silken threads connecting them.
How can the presence of a spider mite be determined? - in detail
Spider mite infestations can be confirmed through several diagnostic steps. Visual inspection of foliage reveals characteristic damage: minute yellow or bronze speckles where the mite feeds, often arranged in a stippled pattern. As the population expands, leaves may develop a bronze‑to‑white discoloration and a fine, silky web on the undersides and between leaf veins. The presence of webbing is a reliable indicator, especially when it obscures the leaf surface.
Sampling techniques provide quantitative data. A leaf brush or fine‑toothed comb can dislodge mites onto a white tray for counting. Collected specimens are examined under a low‑power microscope (magnification 40–100×) to identify the distinctive oval shape, elongated rear legs, and the presence of four pairs of legs in adult females. Immature stages, known as motiles, are smaller but retain the same body outline.
Sticky traps positioned within the canopy capture wandering mites, allowing for early detection before extensive damage occurs. Traps should be placed at canopy height and replaced weekly to maintain effectiveness.
Laboratory analysis expands detection capabilities. Molecular assays, such as polymerase chain reaction (PCR), target species‑specific DNA sequences, confirming identity even when visual signs are ambiguous. Enzyme‑linked immunosorbent assay (ELISA) kits detect mite‑derived proteins and can be applied to leaf extracts.
Integrated monitoring combines these methods: routine scouting for webbing and stippling, periodic sampling for microscopic confirmation, and supplemental trap or molecular testing during high‑risk periods. Prompt identification enables timely control measures, reducing the likelihood of severe crop loss.