How should a gall mite on a pear be treated in summer? - briefly
Apply a summer‑approved acaricide—such as sulfur, horticultural oil, or a registered miticide—directly to infected shoots, repeating the treatment according to label intervals, and prune out heavily infested branches to lower mite populations.
How should a gall mite on a pear be treated in summer? - in detail
Gall mite (Aceria pyri) attacks young pear shoots and leaves when temperatures rise above 20 °C. Effective summer control requires a combination of cultural, biological, and chemical measures applied at specific growth stages.
Cultural actions reduce mite populations and limit damage. Prune out shoots showing gall formation before they harden, removing the material from the orchard to prevent spread. Maintain a canopy that allows good air circulation; thin foliage to lower humidity and temperature inside the crown. Avoid excessive nitrogen fertilisation, which promotes tender growth favored by the mite.
Biological options focus on natural enemies. Release of predatory phytoseiid mites (e.g., Neoseiulus californicus) into the canopy can suppress gall mite numbers. Ensure a pollen source such as Quercus or Corylus to sustain predator populations. Apply horticultural oil (vegetable or mineral) at a rate of 2–3 L ha⁻¹ during the early summer, when mites are active but before larvae harden. Oil smothers mites and their eggs without harming the tree.
Chemical treatments are reserved for severe outbreaks. Select a miticide registered for pear and effective against eriophyid mites, such as abamectin, spirodiclofen, or bifenthrin. Apply at the recommended label dose (typically 0.1–0.2 g a.i. L⁻¹) when shoots are still green and expanding, usually in June. Rotate active ingredients between applications to delay resistance. Observe pre‑harvest intervals to avoid residue violations.
Monitoring is essential. Inspect shoots weekly from May through August, counting the number of galls per 10 cm of shoot. Action thresholds are commonly set at five or more galls per shoot; exceedance triggers the control steps outlined above. Record observations to adjust timing and dosage in subsequent seasons.
Integrated management—combining pruning, canopy management, predator support, oil sprays, and targeted miticide use—provides the most reliable reduction of gall mite damage during the warm months.