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Pear Psylla Management Update March 31, 2022

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By Louis Nottingham, Robert Orpet, WSU Entomology. March 31, 2022

Current pear psylla degree days accumulations as of March 28 are Cashmere 279, Omak 164, Peshastin 222, Wapato 344, Wenatchee 286, Hood River 343, and Medford 578. At 350 PDD, insect growth regulator applications will sterilize pear psylla adults and have little effect on natural enemies. A particle film will also suppress egg-lay if the adult population is still high.

For a full summary of upcoming management at 350 PDD, see below or at the Psylla Phenology Model page, where we also provide weekly PDD updates.

Popcorn, 350 PDD

Conditions:

  • Pear psylla: Pear psylla adults are laying eggs on separated flower pedicels and leaves. Flower buds have closed white petals.
  • Natural enemies: Trechnites wasps are overwintering in parasitized pear psylla nymphs, Campylomma are overwintering as eggs under bark scales, and Deraeocoris adults are present.

350 PDD Conventional Management:

  • Pear psylla:
    • A second particle film application (Surround CF/WP or Celite 610 at 50 lb/acre) will help control egg-lay if only one has been made or if it has been over two weeks since the previous. If pressure is low (less than 2 adults per tray), you may not need the third spray or it can be made with a half-rate (25lb/acre).
    • Particle films do not inhibit honeybees or pollination in pears. There is also no evidence that particle films inhibit the action of pesticides.
    • The insect growth regulator pyriproxyfen (Esteem 35WP) will sterilize pear psylla adults and have little effect on natural enemies. Only two sprays of pyriproxyfen are allowed per year and must be spaced at least 14 days apart.
    • Other selective materials such as Cinnerate, azadirachtin (Aza-Direct or Neemix), diflubenzuron (Dimilin 2L), or buprofezin (Centaur WDG) can be used instead of pyriproxyfen if the 14-day window is not met or you wish to save pyriproxyfen for later.
  • Pear psylla/mealybug: Buprofezin (Centaur WDG), aids in both pear psylla and mealybug suppression at popcorn.

350 PDD ORGANIC Management:

  • Pear psylla:
    • A second particle film application (Surround CF/WP or Celite 610 at 50 lb/acre) will help control egg-lay if only one has been made or if it has been over two weeks since the previous. If pressure is low (less than 2 adults per tray), you may not need the third spray or it can be made with a half-rate (25lb/acre).
    • Particle films do not inhibit honeybees or pollination in pears. There is also no evidence that particle films inhibit the action of pesticides.
  • Pear psylla/mealybug/scale: Use Cinnerate or azadirachtin (Aza-Direct or Neemix) to increase pear psylla adult suppression if needed and suppress mealybug and scale.

350 PDD Not Recommended (Conventional and ORGANIC):

  • Avoid using broad-spectrum insecticides like acetamiprid (Assail), tolfenpyrad (Bexar), malathion (Malathion 5EC), novaluron (Rimon), or lambda-cyhalothrin (Warrior II) because they will harm natural enemies and pollinators, which are abundant as flower petals open.
  • Do not use alternative particle film products such as Microna or Cocoon to control pear psylla, as they have been demonstrated to be significantly less effective than Surround and Celite. They are also not labeled for pear psylla control.

Additional Information

Pear IPM Webpages http://treefruit.wsu.edu/crop-protection/pear-ipm/

Pear Psylla Phenology Model Webpage http://treefruit.wsu.edu/crop-protection/psylla-phenology-model/

Decision Aide System https://decisionaid.systems Now has the Pear Psylla model.

Washington State University