How to determine if spider mites are present on cucumbers? - briefly
Check cucumber foliage for fine silvery webs on the undersides, stippled or yellowed spots, and the presence of tiny moving specks; a quick test is to tap a leaf over white paper and watch for falling mites. Confirm by magnifying the leaf surface to see the eight‑legged pests, which are about 0.5 mm long.
How to determine if spider mites are present on cucumbers? - in detail
Spider mites on cucumber vines can be identified through visual inspection, microscopic examination, and monitoring of plant health. The following steps provide a systematic approach.
Visual cues
- Tiny, moving specks on the underside of leaves; adult mites are less than 0.5 mm in size.
- Fine, web‑like silk strands connecting leaves or covering leaf edges.
- Leaf discoloration: mottled yellow‑green patches that expand into larger necrotic areas.
- Stippling: tiny, white or silver dots where mites have pierced cells.
- Premature leaf drop and reduced fruit size, especially under high temperature and low humidity.
Inspection technique
- Select several leaves from the middle and lower canopy.
- Hold each leaf over a white sheet of paper; gently shake to dislodge mobile mites.
- Observe the paper for specks moving in a zig‑zag pattern.
- Use a hand lens (10–20× magnification) to examine the leaf underside for webbing and stippling.
Microscopic confirmation
- Collect a leaf fragment with suspected damage.
- Place the fragment on a microscope slide with a drop of water.
- Cover with a coverslip and examine at 40–100× magnification.
- Identify the characteristic oval body, four pairs of legs, and the red or brown coloration of adult spider mites.
Environmental indicators
- High temperature (> 30 °C) and low relative humidity (< 50 %) accelerate mite reproduction.
- Over‑fertilization with nitrogen encourages rapid foliage growth, providing a favorable habitat.
Control thresholds
- If more than 10 mites per leaf are observed or webbing covers more than 5 % of leaf surface, immediate intervention is recommended.
By following these inspection steps, growers can reliably detect spider mite infestations on cucumber crops before damage becomes severe.