Biological control agent screening process
Screening is the process of experimentally assessing the host range of the potential
biocontrol agents, to ensure they are specific to the target plant and will not
inflict major damage to other Canadian plants of economic or environmental importance.
FLNRO's Range Branch, on behalf of the province, work closely with entomologists
from Agriculture and Agri-Food Canada (AAFC) to enable the research required to
implement biological control as a means of managing invasive alien plants in British
Columbia. BC's funding contributes to larger funding consortia which pool contributions
from other Canadian provinces, US States and countries such as New Zealand and Australia,
depending on the invasive plant targeted.
Potential biological control agents are investigated and collected in the country of origin of the target plant species in locations with the latitude and habitat types as similar as possible with BC. Agents are usually scarce in their native regions because the plants often exist at low population levels. Additionally, often little is known about their biology and habitat requirements. For these reasons, multiple potential agents will be involved in the initial stages of the screening process for a single plant because it is not known at the outset which agents will successfully pass the host-specificity tests.
Host-specificity tests consist of providing the potential agent with the target invasive plant and a variety of closely related plants of concern to the country where the insect may be released (i.e. plants from BC/Canada). Different life stages of the agent are investigated such as adult starvation and larvae feeding tests. The biocontrol agents must be very host specific in order to be released. The agent must not develop on the other related species, particularly on any rare and/or economically or ecologically desirable plants. If they do attack and develop on these plants , they are either removed from the screening process or further testing is conducted to determine if these species are less preferred than the target invasive plant, or whether they would be avoided in the field if the agent were released (i.e., testing of the species ecological host range). Screening also is used to determine which biological control agents will be effective in controlling the target plant.
If a successful specific biocontrol agent is identified, screening results are used
to submit a petition to request importation of the new biocontrol agent to the Canadian
Food Inspection Agency (CFIA). The petition is reviewed by a panel of experts from
the federal government, universities and often provincial specialists from the province
where the release is proposed. In addition, input is provided from the US Technical
Advisory Group (TAG) for Biological Control of Weeds USDA-APHIS because importation
of a biocontrol agent can have North American implications.
Multiple agents may successfully pass the host-specificity tests. In some circumstances, invasive plant populations can be controlled with a single biocontrol agent. Often several different agents are needed to achieve the desired suppression of invasive plants throughout the variety of ecological and climatic conditions that exist in British Columbia.
Once a successful invasive plant biocontrol agent is introduced, the benefits to costs range from 3:1 to >100:1 depending on the pest targeted. Resulting invasive plant control is persistent, host-specific, self-sustaining (biocontrol agents spread with the invasive plant), cost effective in terms of requiring additional treatments, avoids development of herbicide resistance and has a relatively low environmental impact.
"Healthy, functioning BC ecosystems, free of the impacts of invasive plants."