Contents: By Damage and Image
Boxwood psyllid, Cacopsylla (=psylla) buxi (Linnaeus), is a common pest of boxwood, particularly in landscape settings.
There is one generation a year. Eggs are laid underneath the leaf bud scales. UMass Extension lists egg hatch occurring at 80 Growing Degree Day (GDD) with adults appearing around 300 GDD. The Ohio State University lists egg hatch at 179 GDD (base 50 degree F.). Eggs hatch (eclosure) was noted on April 2 in the North Willamette valley in 2010 (approx. 41 GDD), April 5 in the Portland metro area in 2007 (approx. 77 GDD). Adults were noted May 17 (approx. 229 GDD) in western Oregon in 2012. The Ohio State site indicates full bloom saucer magnolia, Magnolia soulangiana, and full bloom of weeping Higan cherry, Prunus subhirtella, as phenological indicator plants.
Cultural management options include pruning off infested tips prior to adult emergence and egg laying.
True bugs are the most numerous natural enemies of psyllids. Anthocoris amplicollis has been identified as a predator of boxwood psylla in Serbia (Jerinić-Prodanović D, Protić L., 2013). Although there is an array of natural enemies that feed on boxwood pysllid, they generally do not keep damage below commercial nursery thresholds.
Chemical management: Programs relying on "soft" insecticides such as insecticidal soap and horticultural oil time applications just as boxwood growth flushes in the spring to smother the eggs prior to hatch. This must occur before the nymphs feed enough to cause cupping of the leaves, after which they will be protected from these contact sprays. Growers also use systemic insecticides to target this pest, generally applying either in the fall or a couple of weeks before nymphal feeding is expected in the spring.
True bugs are the most numerous natural enemies of psyllids. Anthocoris amplicollis has been identified as a predator of boxwood psylla in Serbia (Jerinić-Prodanović D, Protić L., 2013)
The following websites have information on boxwood psyllid.
Hoover, G. 2001. Penn State Entomology: Boxwood psyllid. November 2001. <accessed 9 March 2016>.
Jerinić-Prodanović D, Protić L. True bugs (Hemiptera, Heteroptera) as psyllid predators (Hemiptera, Psylloidea). ZooKeys. 2013;(319):169-189. doi:10.3897/zookeys.319.4316.
Townsend, L. 2011. Boxwood Psyllid. University of Kentucky Extension. <accessed 9 March 2016>. May 2011. <accessed 9 March 2016>.
University of California Pest Notes: Psyllids has information on a wide variety of psyllids, some of which might be helpful for boxwood psyllid management.<accessed 9 March 2016>.
Author: R.L. Rosetta, Extension Nursery Integrated Pest Management, Department of Horticulture, Oregon State University/NWREC.