The Invasive, Garlic Mustard (Alliaria petiolata)



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SOME STANDARD PRACTICES FOR THE PREVENTION AND CONTROL OF GARLIC MUSTARD

PREVENTING THE INITIAL ESTABLISHMENT OF GARLIC MUSTARD

 

·         Disturb soil as little as possible;

·         For re-vegetation and construction projects, use weed-free mulches, sods, and fill materials;

·         DO NOT IMPORT soils from other sites to project sites;

·         Steam clean gravel at pits, before bringing to construction sites;

·         Remove garlic mustard plants before seeds develop or drop;

·         Remove garlic mustard plants before construction begins;

·         Even on sites where garlic mustard removal has been performed before construction, timber harvest or other soil disturbing  activities have occurred, be sure to wash down or blow off equipment used on these formerly infested sites, before moving equipment to new locations;

·         Partner with adjacent landowners who have garlic mustard infestations on their property to encourage them to control the plant on their land, thus avoiding further spread;

·         Clean off mowers and brush hogs between sites to avoid transporting weed seeds;

·         Train maintenance crews to identify garlic mustard plants in all life stages;

·         Report sightings to one of the five Conservation Districts listed below;

·         Avoid walking, biking, horse-riding, or mowing through infested areas – it spreads the seeds!!

·         Brush off clothing, shoes, pets, camping and other equipment if you’ve traveled through garlic mustard;

·         Learn ways to control garlic mustard by contacting the Conservation Districts listed below.

 

 

                                                                  

ACTIVE CONTROL OPTIONS FOR GARLIC MUSTARD

 

·         Hand-pull plants (especially second-year ones) before seed development;

·         Cut garlic mustard in early spring, then cut second time later in growing season;

·         Cover with material to suppress and kill garlic mustard;

·         Use Prescribed Burns;

·         Use herbicides (particularly in fall);

·         Use biological control agents when they become available (expected in 2007 or 2008).

 

DETAILS ABOUT CONTROL METHODS (OFTEN USED IN COMBINATION)

 

     HAND-PULLING

 

·         Crew of 3 to 5 people, sometimes more;

·         Work from outer edge of population, inward;

·         Concentrate on pulling mature plants before, during or very shortly after flowering state;

·         Bag on site in black plastic bags to reduce off-site transport;

·         Do NOT attempt control when seeds are ripe – it risks further spread!!!

 

 

    CUTTING IN EARLY SPRING

 

 

·         Use scythe, monofilament weed whip, or power brush cutter;

·         For a single-season cut, there is only a narrow window to perform cutting operations for control – MOST single control cuts have greatest effectiveness during the brief period of stalk elongation just before flower formation.  (Reason – the root crown is less likely to re-sprout).  Use of a power brush cutter, is a possible exception.  Can cut earlier if power brush cutter is used and root crown is severed below soil surface;

·         If cutting period progresses to a date when viable seed can develop (seed pods are formed or have started to form), must remove cut plants from treatment site.

 

 

    COVERING WITH MATERIAL

 

 

·         Good for small infestations, such as those along the perimeter of a parking lot, or in a ditch;

·         Material =thin rubber matting or heavy grade plastic “Visqueen”’

·         Leave in place for extended time and check periodically for tears.

 

 

    HERBICIDE TREATMENTS

 

 

·         For good kill rates of garlic mustard and lowered impacts to non-target plants, fall and winter (no snow cover) herbicide use can be ideal – so long as conditions are suitable and garlic mustard is actively photosynthesizing (possible starting as low as 45 degrees Fahrenheit).  Usually the window for fall treatments are mid to late October thru late November in northern lower peninsula;

·         Early spring (after snow melt, but well in advance of green up of other plants) – again because garlic mustard actively photosynthesizes while most other plants are dormant this can be a good time to treat with herbicides, especially in roadside rights-of-way which do not contain a lot of native plants.  However, must consider effect to early spring plants, which may be present at that time;

·         Preferred Herbicides:  Glyphosate (e.g., Round-Up etc.) at a formulation of 41% active ingredient reduced to a rate of 3% active ingredient when applied.  Use a surfactant, such as Silkin (2 to 3 drops/gallon) and a dye (to help identify spray locations.);

·         Use with backpack sprayer or wicking device.  (back-pack spraying is more efficient, but is more prone to off-target drift).

 

 

 

    PRESCRIBED BURNING
             (used in highly infested sites with good leaf-litter build up, preferably of oak leaves):

 

 

·         Can reduce seed bank;

·         Deters existing mature plants from producing seeds;

·         Sets back existing rosette growth and kills some first year plants;

·         Makes herbicide treatments and hand-pulling easier after burns;

·         NOTE:  Treatment effectiveness should be monitored throughout the season; as, burning has been known to stimulate seedling growth when burns are too cool.

 

 

IMPORTANT CONSIDERATIONS FOR ALL GARLIC MUSTARD CONTROL PRACTICES

 

 

·         Ensure that all who participate in control projects use a brush or other tools to remove seeds from shoes, clothes, and equipment before leaving infested area;

·         Always return to treatment sites to evaluate effectiveness.  Examine sites two weeks following treatment.  Then, revisit twice more late in the growing season to catch stragglers and perform any “clean-up” treatments (typically via pulling, spot burning or spot use of herbicides);

·         Quit all mowing and all control efforts on sites where garlic mustard seed pods are ripe, to avoid transport and further spread of seeds.

 

 

 

 

                 LOCAL CONTACTS:

                *BENZIE COUNTY:  231-882-4391
                *LEELANAU COUNTY:  231-256-9783

                *MANISTEE COUNTY:  231-889-4761

                *MASON-LAKE COUNTY:  231-757-3708

                *OSCEOLA-LAKE COUNTY:  231-832-2950