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WELCOME

INTEGRATED WEED MANAGEMENT

INTRODUCTION

• Weed control is essential for succesful crop production , as weeds are ever present in the soil and potentially reduce crop yield every year.

• IWM is the component of IPM and the three elements of IPM are:

• (1) multiple tactie s of pest management used in a compatible manner,

• (2)pest populations maintained below levels that cause economic damage , and

• (3)conservation of environmental quality.

Integrated Weed Management (IWM) is the combination of multiple management tools to reduce a pest population to an acceptable level while preserving the quality of existing habitat, water, and other natural resources. Combinations of biological, mechanical, and chemical management practices are utilized in IPM programs to efficients during the pest’s lifecycle or

growing season.

For example, an IWM program for Canada thistle, Cirsium arvense, may consists of multiple management scenarios throughout the growing season to achieve the most efficient suppression of this invasive weed in contrast to using any one given management practice by itself. Below are listed steps throughout the growing season that may be followed in a one-year Canada thistle IWM management strategy

IWM STRATEGY

• Fall [late september ,october]: spot spray or broadcast thistle plants/ro settes, over seed area with competative native grasses and forbs

• Early spring [april-early may]:spot spray (or selectively broadcast) thistle ro settes with a selected herbicide ; use a controlled burn to destroy remnant vegetation and seeds on the soil surface

• Late spring (may – early june):spot spray any emerging thistle plants.

• Summer (late june –early august) : Mow thistle patches prior to seed development, relese canada thistle biological control agents.

BIOLOGICAL CONTROL• Biological control as it applies to weed management , is the use of plant

feeding insects , pathogens, or disease that are host- specific to a noxious or invasive weed species, with the intension of suppresing the weeds population to an acceptable level. Biological control agents are specific to the plant they are intended to control . In other words , the biological cotrol agent freeds and develops only on the intended weed species terefore, the risk to other plants and organisms the ecosystem is minimal.

• Biological control is intended to be a cost- effective and long-term solution to weed management . It may take several years for biological control agents to established but once their population begin to build up to appropriate levels they provide long-term suppresion and reduce management cost significantly . Leafy spurge, purple loosestrife, and spotted knap weed are all examples of noxious and invasive weed species where biological control is succesfully being used in minnesota.

CHEMICAL CONTROLS• Chemical control in weed management is the use of synthetic or

naturally occuring compounds that are applied to noxious and invasive weed species with the intent of killing those plants . Chemicals (herbicides ) range in selectively to certain types of plants and their persistence within the environment.

• Herbicides are typically applied in granular or liquid form some types of herbicides areapplied before weeds germinate (pre-germinate) and others are applied after germination (post-emergent) .Extreme caution must always be followed when handling are attempting to work with any herbicides .

• By law all herbicides must be labelled according to their use and users must adhere strictly to labbeled instructions and warnings.

• Chemical controls are usually short-term solutions to weed problems.