Pests image: Buckthorn


Glossy buckthorn (Rhamnus alnifolia), and common (European) buckthorn (Rhamnus cathartica) are invasive shrub or small tree species in North America. Buckthorn grows vigorously and spreads aggressively, invading urban and commercial forests, road and trail sides, riverbanks, pastures, and hydro corridors. Buckthorn outcompetes natural regeneration and displaces native plant species. It can alter ecosystems for both flora and fauna, and significantly affect soil by, for example, increasing soil pH.

The disappearance of over-story ash trees due to the Emerald Ash Borer has exasperated this issue further, allowing buckthorn to upset natural regeneration in our native forests.  Natural land managers, non-profit organizations, and municipalities alike who are dealing with buckthorn may be limited in management options due to restrictions/ limitations on products currently available.

Chondrostereum purpureum (Cp) should be applied in late spring to early summer when buckthorn is fully leafed out. Typically, application should occur from mid-June to early July but can also be dependent on geographical location and growing degree days. Conditions should be conducive for fungal growth and infection which includes some shading from direct sun:

  • If operations for control include cutting stumps, it is recommended to have an over story species present that provides some shade to allow for incubation and colonization of the Chondrostereum purpureum (Cp).
  • If operations for control include girdling stems, then the buckthorn canopies of the girdled stems can provide shade to optimize fungal colonization. It is expected for canopies to remain alive for the rest of the growing season, post girdling.

A thin layer of product should be applied to a freshly cut stump or girdle wound within 30 minutes of cutting.

It’s important to note that re-sprouting occurs post-treatment (cutting and application). These sprouts will be weakened and infected with silver leaf disease: a sign that the Cp is established and working. Because of its biological nature, Cp can take up to 24 months to fully colonize treated stems.

Featured Treatments




LALCIDE CHONDRO (Registration Number 29293 PCP) has Chondrostereum purpureum, a naturally occurring fungal plant pathogen, as its active ingredient. LALCIDE CHONDRO is currently registered as a biological herbicide for the inhibition of re-sprouting and regrowth from cut stumps of alders (red, thin leaf, and Sit...