Research Branch

See below to download.

Field Guide to the Biological Control of Weeds in British Columbia

Author(s) or contact(s): G.W. Powell, A. Sturko, B.M. Wikeem, and P. Harris
Source: Research Branch
Subject: Vegetation Management
Series: Land Management Handbook
Other details:  Published 1994. Hardcopy is available.


The biological control of weeds typically involves the local establishment of host-specific organisms from other parts of the world to give continuing control of weeds. Weeds reduce floral diversity and the capacity of land to support wildlife, livestock, trees, and recreational activities. The biological control of weeds has a long history as an economically sound and environmentally friendly method of controlling widespread introduced weeds on uncultivated land.

In Canada the biological control of weeds began in British Columbia in 1952 with the release of the defoliating beetles Chrysolina quadrigemina and C. hyperici to control St. John's wort. Although initial results of that trial were disappointing, within 13 years of the release the beetle populations had increased sufficiently to control the weed in most areas of the province, eliminating the need for chemical control of this species. From these early beginnings, biological control of weeds has expanded to most provinces of Canada, and the program now uses more than 50 insects and pathogens on more than 20 different introduced weed species.

This guide is designed to help resource managers in British Columbia identify weeds and select suitable biological control agents for those weeds. Biological control offers stable, long-term solutions to weed problems across the province.

Download Land Management Handbook 27 PDF file (complete document) (6367 KB)

Cover to page 42 (download in 4 parts) (1816 KB)

Page 43 to page 52 (119 KB)

Page 53 to page 96 (1288 KB)

Page 97 to end (1869 KB)

To view this document you need the current version of
Adobe Acrobat Reader, available free from the Adobe Web Site.

Updated May 08, 2007