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Cecidophyopsis psilaspis

Taxus bud mite galls. Photo: Jean-Yves Baugnée.
Scientific Name: 
Cecidophyopsis psilaspis
Common Name: 
Taxus Bud Mite
Growing Degree Days (GDD's): 
148–448 GDD's; 707–912 GDD's, Base 50F, March 1st Start Date. (Source: Robert Childs, UMass Extension and Cornell Cooperative Extension.)
Host Plant(s) Common Name (Scientific Name): 
English yew (Taxus baccata)
Pacific Yew (Taxus brevifolia) *Records from British Columbia, Canada.
Yew (Taxus spp.)
Insect Description: 

The taxus bud mite is a species of eriophyid mite that is sometimes a significant pest of yew (Taxus spp.). It is common in several Northeastern states, and widely distributed throughout Europe. Despite the eriophyid mite being described over a century ago, very little is known about the specifics of its biology and life cycle. The mites pass through an egg, larva, nymph, and adult life stage. Taxus bud mites crawl between host plant bud scales, the location where they overwinter. By late summer and fall, feeding and reproduction of the mites occurs. As many as 1,000 individual taxus bud mites may live in a single bud. As new buds are formed in the summer, taxus bud mites migrate to them to begin their life cycle anew (Johnson and Lyon, 1991). In British Columbia, Canada, mites colonize both vegetative and reproductive buds and peak in their activity from May to August with lowest numbers in March and October. The height of taxus bud mite activity in that study was observed in June (Marshall and Clayton, 2004). Taxus bud mite showed preference for terminal and lateral buds on Pacific yew compared to reproductive, axillary, or latent buds. In British Columbia it is hypothesized that the taxus bud mite was introduced to Pacific yew from English yew (T. baccata) (Mitchell et al., 1997). Magnification is required to observe the taxus bud mites themselves. According to Marshall and Clayton (2004): "using a dissecting microscope, larvae of C. psilaspis can be identified by their small size (average length 96 µm) and translucent or white coloring; nymphs by their larger size (average length 130 µm) and white, or translucent with orange-blotch, coloring; and adults by their larger size and orange–brown coloring".

Damage to Host: 

Twigs and buds of the host plant are impacted. The taxus bud mite causes deformed buds and needles on its hosts. Attacked buds may sometimes perish following enlargement and "blasting" (wither and fall or abort from an otherwise healthy plant). Secondary microorganisms can cause decay of the damaged buds. Heavily infested buds will not grow in the spring. Lighter infestations may result in distorted needles and shoots. 


Monitor buds visually for signs of swelling or decay. Infested host plants may also have distorted needles or shoots. Magnification is required to observe the mites or their eggs.

Cultural Management: 

Infested branches may be pruned out and destroyed.

Natural Enemies & Biological Control: 

Temperature and predation are assumed to be significant factors in population fluctuation of the taxus bud mite. It is hypothesized that taxus bud mite abundance increases following favorable spring temperatures and availability of new food resources, whereas predation by other mite species and lower temperatures, which prolong development, may cause the low population numbers of bud mites in March and October (Marshall and Clayton, 2004). Potential natural enemies of the taxus bud mite include but are not limited to: phytoseiid mites, Epitrimerus gemmicola, and Pentamerismus taxi (Marshall and Clayton, 2004). 

Chemical Management: 

Abamectin (NL)

Carbaryl (L)

Horticultural Oil (L)

Pyrethrins (L)

Pyrethrin + piperonyl butoxide (L)

Spiromesifen (L)


Active ingredients that may be applied systemically include: abamectin (injection) and neem oil (soil drench).

Make insecticide applications after bloom to protect pollinators. Applications at times of the day and temperatures when pollinators are less likely to be active can also reduce the risk of impacting their populations.

Note: Beginning July 1, 2022, neonicotinoid insecticides are classified as state restricted use for use on tree and shrub insect pests in Massachusetts. For more information, visit the MA Department of Agricultural Resources Pesticide Program.

Read and follow all label instructions for safety and proper use. If this guide contradicts language on the label, follow the most up-to-date instructions on the product label. Always confirm that the site you wish to treat and the pest you wish to manage are on the label before using any pesticide. Read the full disclaimer. Active ingredients labeled "L" indicate some products containing the active ingredient are labeled for landscape uses on trees or shrubs. Active ingredients labeled "N" indicate some products containing the active ingredient are labeled for use in nurseries. Always confirm allowable uses on product labels. This active ingredient list is based on what was registered for use in Massachusetts at the time of publication. This information changes rapidly and may not be up to date. If you are viewing this information from another state, check with your local Extension Service and State Pesticide Program for local uses and regulations. Active ingredient lists were last updated: January 2024. To check current product registrations in Massachusetts, please visit: .