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Garlic Mustard Alliaria pe)olata Cornell University Coopera5ve Extension History • Introduced from Europe 1800s • Gene5c studies indicate introduced mul5ple 5mes • Used for medicinal purposes • Cooked as potherb — early season source of Vitamins A & C Growth • Biennial • Germinates in spring and late summer • Grows as basal roseIe first year • Remains green throughout winter • Second year plants send up flower stalk, bloom, seed & die Habitat Adaptable • Upland and flood plain forests • Savannas • Riverbanks • Roadsides • Invades forest edge, progressing to the interior along streams & trails • Prefers shade, tolerates sun • Cannot tolerate acidic soils Threat to Environment • Prevents na5ve plants from geQng the light, moisture, and nutrients they need • Can displace most herbaceous na5ve plants within 10 years • Na5ve toothwort (Dentaria) is one of first casual5es • Smothers tree seedlings, reducing replacement of trees Threat to Environment Major threat to survival of na5ve woodland vegeta5on & wildlife that depends on it Threat to Wildlife Because of GM’s abundance, buIerflies lay their eggs on the plants, but the larvae fail to survive due to the different chemistry of the GM* leaves West Virginia white, Pieris virginiensis, is considered par5cularly threatened by the spread of GM *GM = Garlic Mustard GM’s Weapons • Monoecious — single isolated plant can produce 1000s of seeds • Tolerates cold weather — greens up earlier, lasts longer into the season • Aggressive growth rate • Seeds remain viable an average of 5 to 7 years • Seeds have varying lengths of dormancy — can germinate mul5ple 5mes throughout year GM’s Weapons • Offensive odors and chemicals protect from animal grazing • No na5ve insect uses GM as food source • Allelopathic — Roots emit glucosinolates – toxins which kill soil fungi Glucosinolates? • Kill soil fungi — Na5ve plants rely on soil fungi to facilitate uptake of phosphorous, nitrogen & water • Over a period of 30 years, produced lower levels of fungicidal compounds – Allows the start of na5ve plant return – Conserva5on efforts might be more effec5ve focusing on recently invaded areas where most damage occurs How Bad Is It? PreIy Bad! … and this is the minimum number of sigh5ngs confirmed by the USDA!
Garlic Mustard is widespread in at least the northern ¾ of Illinois … and could have infiltrated southern coun5es also!
Images -­‐ USDA Plants Database Descrip5on How do I tell? The Smell! Ground Ivy or Creeping Charlie Everyday Infinity 1st yr Garlic Mustard RoseIes Na5ve Violets 2nd Yr Leaves Alternate Sharply toothed Heart-­‐shaped to triangular Flowers Toronto Gardens Blogspot Terminal Tight clusters Small (1/4” diam) 4-­‐petaled Flowers progress upwards as seedpods form below. Seed Capsule Upturned Thin Green ripening to tan and papery Exploding to expel 5ny black seeds Cornell University Coopera5ve Extension Seeds • Sole means of reproduc5on • Viable within days of ini5al flowering • Can remain viable for up to 10 years! Dispersal Floodwaters Wild California Off-­‐Road Vehicles American Hiking Society Hikers Dispersal Wildlife Get-­‐Rid-­‐of-­‐Pests.com Manataka Control Mechanical • Best control is preven5on! • Hand-­‐pulling – Can be pulled any5me the soil can be worked – Because of the glucosinolates, it is advisable to remove the root – Preferred method when na5ve plants are present Hand-­‐Pulling Strategy • Dense patches of new seedlings self-­‐select — control efforts usually emphasize removing 2nd year plants before seed dispersal • Larger patches of Garlic Mustard – determine outer edges – remove plants working from least infested to most infested (outer edge of patch to center) Hand-­‐Pulling Strategy • Forced Choice to Reduce Spread of GM: – Eliminate individual plants – Eliminate small patches – Work on larger patches from outer edges inward Disposal • Plants in bloom can con5nue to produce seed – Flowers & seed heads must be bagged and removed from the area • Plants should be allowed to turn to slime within plas5c bags • Compos5ng does not kill the seeds • Burning is an acceptable disposal method if allowed by the community Control Mechanical • CuQng – Ideal 5ming: approaching or at very start of flowering stage – Poor 5ming (earlier than flowering stage) may lead to resprou5ng with mul5ple stems – May also expose small, previously hidden plants to more light, allowing them to grow more vigorously & mature aqer cuQng has taken place Control Mechanical • Prescribed fire – Early spring before na5ve plants emerge – Late fall – Effec5ve as long as fire is hot enough to burn all leaf liIer – May be more effec5ve in fall when more leaf liIer is available as fuel Control Chemical • 2,4-­‐D (Weed-­‐Pro, Jus5ce, Trimec, etc) – broadleaf herbicide • Glyphosate (Roundup) • Non-­‐selec5ve herbicide • More commonly used on GM than other herbicides • Applied in fall or very early spring when most na5ve species are dormant Control Chemical • Glufosinate-­‐ammonium – Preliminary tes5ng on roseIes encouraging – Rapidly degrades – Does not have residual soil ac5vity • Corn gluten – Non-­‐selec5ve – Early experiments applied to soil where seeds have dispersed have shown some success as pre-­‐
emergent alterna5ve Control Biological • Research for a successful, exclusive bio-­‐agent con5nues and includes: – Several beetles – Fungal diseases Important Note Because of the long-­‐term viability of the seed, Monitoring and Control efforts must con5nue over a period of 10 years A Resource to Share A Few Resources to Use • Nonna)ve Invasive Plants of Southern Forests: A Field Guide for Iden)fica)on and Control — James H Miller, USDA, 2004 • Invasive Plants: Guide to Iden)fica)on and the Impacts and Control of Common North American Species — Sylvan Ramsey Kaufman & Wallace Kaufman, Stackpole Books, 2007 • www.weedcenter.org And a Couple More • Exo)c, Invasive Species in Illinois — Illinois Natural History Survey • Invasive Plants of the Upper Midwest: An Illustrated Guide to their Iden)fica)on and Control — Elizabeth J. Czarapata, University of Wisconsin Press, 2005 Garlic Mustard