How to combat the pear psylla? - briefly
Apply horticultural oil or insecticidal soap at bud break and repeat after rainfall, while pruning and destroying infested shoots. Complement treatments with yellow sticky traps and encourage natural predators such as lady beetles and lacewings for sustained control.
How to combat the pear psylla? - in detail
Pear psylla (Cacopsylla pyri) is a sap‑sucking hemipteran that attacks pear trees. Adults emerge in spring, lay eggs on young shoots, and nymphs develop through several instars before becoming reproductive adults. Overwintering occurs as eggs on bark or as adult females in protected sites. Multiple generations may appear in warm climates, increasing population pressure.
Effective monitoring relies on regular scouting and trapping. Visual inspections should focus on the underside of leaves and newly formed shoots, where nymphal colonies are most visible. Yellow sticky traps positioned at canopy height capture flying adults and provide a quantitative index of infestation levels. Thresholds for action depend on cultivar susceptibility and local climate, but counts exceeding 5–10 adults per trap per week typically warrant intervention.
Cultural practices reduce habitat suitability. Pruning removes infested shoots, improves air circulation, and limits oviposition sites. Sanitation of fallen leaves and fruit eliminates overwintering eggs. Selecting pear varieties with documented tolerance to psylla damage further diminishes risk. Maintaining optimal nutrition and irrigation reduces plant stress, making trees less attractive to the pest.
Chemical control must follow precise timing to target the most vulnerable stage—early nymphs on young foliage. Systemic neonicotinoids, organophosphates, or pyrethroids are applied as foliar sprays at the first sign of colonization, respecting pre‑harvest intervals and resistance‑management guidelines. Rotating active ingredients with different modes of action prevents selection of resistant populations.
Biological agents contribute to long‑term suppression. Predatory lady beetles (Coccinellidae) and lacewings (Chrysopidae) consume nymphs and adults. Parasitic wasps (e.g., Aphidius spp.) lay eggs inside psylla nymphs, leading to mortality. Entomopathogenic fungi such as Beauveria bassiana can be sprayed onto foliage to infect all life stages. Conservation of these natural enemies is enhanced by avoiding broad‑spectrum insecticides and providing flowering strips for nectar sources.
An integrated pest management program combines the above elements:
- Conduct weekly scouting and trap counts.
- Apply pruning and sanitation immediately after detection.
- Deploy targeted chemical sprays when nymphal thresholds are exceeded.
- Encourage and, if necessary, augment populations of predators and parasitoids.
- Record all actions to refine thresholds and timing in subsequent seasons.
Coordinated implementation of monitoring, cultural, chemical, and biological tactics yields sustainable control of pear psylla, protecting yield and fruit quality while minimizing environmental impact.