Summary by Tianna DuPont, WSU Extension. April 5, 2026. Reviewed by Chris Adams, OSU Entomology; Tobin Northfield, WSU Entomology and Betsy Beers, WSU Entomology.
If you are transitioning to a selective integrated pest management (IPM) program for psylla don’t forget to implement codling moth controls. Broad spectrum materials used in a standard psylla program often manage codling moth and transitioning to selective materials for psylla can lead to codling moth problems if controls are not implemented.
Codling moth management should include mating disruption and effective use of selective pesticides. Mating disruption is the base for codling moth IPM making all other controls work better. Install dispensers by 175 DD at 300-400 point sources per acre. If using active dispensers (puffers), supplement upwind borders with passive dispensers (ties). First generation ovicide timings are 225 – 275 DD for a residual ovicide or 375 DD with a topical ovicide (e.g., oil). Larvicides are timed at 425 DD (if an ovicide was not applied) or 525 DD (delayed cover approach) followed by an additional spray(s) 5 to 14 days later (depending on the residual). For second and third generations of codling moth, rotate to a different mode of action, adding 1000 DD to the previous timings (eg. for Delayed Cover, 1375 DD is timing for an ovicide, 1525 DD is timing for a larvicide + oil, and then follow up sprays based on product residuals), and consider trap catch to determine if treatment is necessary.
Ovicides considered selective and compatible with pear psylla natural enemies include: oil, pyriproxyfen (Esteem/ Reemit), diflubenzuron (Dimilin 2L), and methoxyfenozide (Intrepid 2F). Methoxyfenozide (Intrepid 2F) (Group 18) for codling moth should be applied before egg hatch and is considered to be low risk for most natural enemies. In efficacy studies it has provided 89 percent control (Van Steenwyk and Nomoto 2002) and 95 percent control (Van Steenwyk and Weiss 2015). Pyriproxyfen (Esteem/ Reemit) reduces egg hatch. Esteem works as a residual ovicide for codling moth.
Chlorantraniliprole (Altacor) (Group 28) is often used as a larvicide (with oil) compatible with IPM. Altacor affects codling moth larvae both via ingestion and contact by binding to receptors which control muscles leading to paralysis and death. It is considered to have high efficacy on codling moth and limited negative impact on natural enemies (Gontijo et al. 2015; Roubos et al. 2014). Oil plus diflubenzuron (Dimilin 2L), methoxyfenozide (Intrepid 2F), or granulovirus (e.g., Cyd-X HP, Madex HP, Madex XLV) are options with reduced risk to natural enemies of pear psylla. GS-omega/kappa-Hxtx-Hv1a (Spear Lep) may be another compatible product which is specific to lepidopteran pests. Diflubenzuron (Dimilin 2L) (Group 15) is considered an ovicide or larvicide (depending on the resource). Its mode of action includes inhibition of cuticle deposition, chitin formation, and inhibition of DNA synthesis. In trials percent control of diflubenzuron compared to the untreated check (based on infected fruit infected or fruit with stings) has ranged from 76-90 percent (Dunley et al. 2002), 87 percent for Dimilin+oil (Van Steenwyk et al. 2004), 89 percent (Van Steenwyk and Nomoto 2002), to 98 percent (Van Steenwyk et al. 2003). It is important to include oil with Dimilin applications (Van Steenwyk and Nomoto 2002).
Additional Information
Contact
Tianna DuPont
WSU Extension Specialist, Associate Professor
tianna.dupont@wsu.edu
(509) 713-5346
References
Dunley, J. E., Greenfield, B. M., and Bennett, L. H. 2002. Control of codling moth in pears, 2001. Arthropod Management Tests 27.
Gontijo, L. M., Celestino, D., Queiroz, O. S., Guedes, R. N. C., and Picanço, M. C. 2015. Impacts of azadirachtin and chlorantraniliprole on the developmental stages of pirate bug predators (Hemiptera: Anthocoridae) of the tomato pinworm Tuta absoluta (Lepidoptera: Gelechiidae). Florida Entomologist 98:59-64.
Roubos, C. R., Rodriguez-Saona, C., Holdcraft, R., Mason, K. S., and Isaacs, R. 2014. Relative Toxicity and Residual Activity of Insecticides Used in Blueberry Pest Management: Mortality of Natural Enemies. Journal of Economic Entomology 107:277-285.
Van Steenwyk, R. A., and Nomoto, R. M. 2002. Codling moth control in pears, 2001. Arthropod Management Tests 27.
Van Steenwyk, R. A., and Weiss, G. B. 2015. Control of codling moth in pears, 2013. Arthropod Management Tests 39.
Van Steenwyk, R. A., Nomoto, R. M., and Zolbrod, S. K. 2003. Codling moth control in pears, 2002. Arthropod Management Tests 28.
Van Steenwyk, R. A., Nomoto, R. M., and Zolbrod, S. K. 2004. Codling moth control in pears, 2003. Arthropod Management Tests 29.
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