Spider mite on raspberry – what to do? - briefly
Apply a targeted miticide or horticultural oil to affected canes, repeating treatment after 7–10 days, and remove heavily infested foliage. Maintain canopy humidity above 60 % and avoid excessive nitrogen to reduce future infestations.
Spider mite on raspberry – what to do? - in detail
Spider mites can rapidly colonize raspberry vines, especially under hot, dry conditions. Adults and juveniles feed on leaf tissue, causing stippling, yellowing, and webbing that reduces photosynthetic capacity and fruit quality.
Identification relies on observing fine webs on the undersides of leaves, tiny moving dots (0.5 mm long) and the characteristic mottled leaf surface. Sampling with a hand lens confirms presence; a leaf wash onto a white tray can reveal the population density.
Control measures should follow an integrated approach:
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Cultural tactics
• Maintain adequate soil moisture; regular irrigation lowers leaf temperature and hampers mite development.
• Remove and destroy heavily infested foliage to reduce the initial population.
• Provide a barrier of mulch to suppress weed hosts that may harbor mites. -
Biological agents
• Release predatory mites (e.g., Phytoseiulus persimilis, Neoseiulus californicus) at a rate of 1 – 2 million per hectare.
• Apply entomopathogenic fungi such as Beauveria bassiana according to label instructions; repeat applications every 7–10 days during outbreaks. -
Chemical options
• Use horticultural oil or neem oil at full coverage; repeat after 7 days to target newly hatched stages.
• Select miticidal soaps with a concentration of 2–3 % active ingredient; apply in the early morning or late afternoon to avoid leaf scorch.
• Reserve synthetic acaricides (e.g., abamectin, spirodiclofen) for severe infestations; rotate modes of action to prevent resistance. -
Monitoring
• Inspect vines weekly during peak season (June–August).
• Record mite counts per leaf; initiate treatment when thresholds exceed 5 mites per 10 cm².
Resistance management demands alternating biological and chemical tactics, limiting any single product to no more than three consecutive applications. Proper timing, thorough coverage, and adherence to label rates maximize efficacy while preserving beneficial organisms.