Integrated Pest Management

Integrated Pest Management (IPM) is the application of multiple management actions that are mutually supportive, and should include actions that cultivate competitive desirable plants and actions that suppress weed populations. The goals of IPM beyond weed control include reducing the cost of weed management and risks associated with herbicidal application. Keys to successful IPM include understanding the biology of the weed, understanding the ecology of the system, and careful planning. The biology of diffuse knapweed important to IPM has been outlined above and can be used to time control actions targeting specific life stages of the weed:

1. to reduce early summer rosette density,
2. to increase mortality during the transition from the rosette stage to the flowering plant stage,
3. to reduce flowering plant survival, and
4. to reduce the number of seeds produced per flowering plant. Knowledge of the ecology of the system including climate, soil, and biotic community are important factors to consider when designing herbicidal, biological, grazing, and cultural management.

Careful planning is based on three factors: overall management goals, measured threats or risk to management goals, and measured progress toward reaching those goals. Specific weed management goals will fit into one of the following categories: prevention, early detection and small-scale eradication, containment, and large-scale population reduction. Prevention is guided by how diffuse knapweed spreads and its requirements for establishment. Early detection and small-scale eradication is achieved through persistent scouting and well-timed herbicide application. Diffuse knapweed populations are contained by herbicidal control of population borders and satellite populations, control actions that reduced seed production, and cultivation of competitive plants. Large-scale population reduction is achieved over the long-term by applying control measures that reduce diffuse knapweed population fitness, such as biological control by the Larinus weevil, and vegetation management options that increase the fitness of desirable plant populations, such as prescribed grazing.

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Last Modified: 06/02/2008