The Invasive, Garlic Mustard (Alliaria petiolata)



Garlic Mustard Links -

GM HOME & IDENTIFICATION

GM CWMA

GM REPORT SIGHTINGS
GM CONTROL
GM VOLUNTEERISM

Preventing the initial establishment of Garlic Mustard

• Disturb soil as little as possible;
• For re-vegetation and construction projects, use weed-free mulch, 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 in all life stages.

Active control options for Garlic Mustard

• Hand-pull plants (especially second-year ones) before development
• Cut garlic mustard in early spring, then cut second time later in
• 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 (used in combination)

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 flower 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 sites.

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";

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 treatment 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 Herbicide:  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 (2-3 drops/gallon) and a dye (to help identify spray locations).

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

        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 later 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.
   Avoid walking, horse-riding, or mowing through infested areas.  It spreads the seeds!!

Local Contacts:   

     

         Benzie Conservation District                                231-882-4391

• Leelanau Conservation District                 231-256-9783
• Manistee Conservation District                 231-889-4761
• Mason-Lake Conservation District             231-757-3708
• Osceola-Lake Conservation District           231-832-2950