There is Asana and Assail amongst other synthetic interventions, but this is a pest that quickly develops resistance so oil is usually part of the program. where it is a serious problem up to a 3% oil treatment is used at first growth with a follow up more dilute spray 10 days later.
Commercial growers in the east are also often using Surround, which is quite effective at suppressing this pest with no resistance issues. I just hate having to use the messy stuff.
Thanks
For anyone not familiar with psylla here is a link http://jenny.tfrec.wsu.edu/opm/displaySpecies.php?pn=120 . Control is difficult in some areas but dormant sprays are said to help. I use rootstock resistant to causing pear decline. Harbin pear rootstock with European pears are said to be highly susceptible to decline caused by psylla.
They are on the small side (1/10" adult) at least I know what Iām looking for now.
Thanks, Clark for the link. I have to look for them.
I have had pear blister mites. Lime-slufur at bud break has worked out well for mites.
They are so small that my pears suffered for a couple years before I got up to speed. I need a glass to see them.