Sept 1-12 Michigan Organic Listserv


             1. Handing vandals

Agriculture Updates

            2. Canada thistle management strategies for sustainable and organic farming systems

          3. Vegetable Production and Pest Management-Aphids on Pumpkin Fruit

           4. Applications for 2009 State Pesticide Notification and Organic Farm Registries Being Accepted


5. Cover Crop Plot Tour: Can Cover Crops Reduce Your Fertilizer Bill?

September 16 from 8:30 to 11:30 a.m.


6. Twilight Tour of MSU Corn Variety Trials: September 15

from 6:00 to 8:30 p.m.


7.  Hoophouse Workshop Thursday, September 25


8. Economics of Low-input Field Crop Systems

Oct 1, 2008 at Kellogg Biological Station

9. Gearing up to increase production: An equipment day for vegetable farmers Oct 2 at SWMREC, Benton Harbor 9-3

10.  Michigan Food & Farming Systems 10th Anniversary Benefit Reception on September 18, 2008 and Embrace Local Food and Michigan Farmers


Job Opportunities

11. National Service AmeriCorps*VISTA Positions At Growing Hope in Ypsilanti, Michigan



There IS hope for the flowers and... the next generation.

1. Handing vandals <>  


Running a school garden in a tough neighborhood requires patience and compassion-and often yields surprising results.

By Katie Olender



It started with a few tomatoes smashed on the driveway near the garden. Then, pumpkins were splattered throughout the parking lot. After that, the picnic table was spray-painted and a few weeks later, one of the benches on it was snapped in half. For months, plants continued to be ripped out or vegetables prematurely harvested and crushed on the sidewalk or left to whither in the sun. One weekend I visited the garden after midnight to cut mint for our garden party the following day and found the shed destroyed, with the walls laying on the ground and the tools spilled out.

That fall, less than a week after six classrooms helped cover the hoophouse frame with plastic, someone slashed it with knives and threw bricks through its walls. The following day, the students still planted seeds inside the tattered hoophouse as planned. We had intended to teach the students how the hoophouse would allow the seeds to grow throughout winter. Instead, we fielded questions from dismayed students who didn't understand why the sides of their brand new hoophouse had been sliced, and from the police and reporters who recorded and photographed the damage. One first grader suggested that maybe the vandals were "jealous because we have vegetables and they don't, or maybe they're just bad."

Though we have faced much vandalism, the community as a whole is supportive of the garden and hoophouse program. Neighbors chase away kids who seem suspicious and call me or the police when they discover more vandalism has occurred. Police officers drive past the garden more frequently now, and the city, school district, and our local water and light company installed a security light that shines on the hoophouse at night. Still, incidents do occur.

One August afternoon (in the midst of the vegetable-smashing episodes but pre-hoophouse slashing) my phone rang. I became instantly alert upon hearing the frantic voice on the other end of the line.

"It's them, they're out there!" said one of the neighbors whose home faces the garden. "They're ripping out plants. I'm watching them from my kitchen window!"

I rushed to the school, and as I rounded the corner I saw four boys pulling out tomato plants and casually tossing them on the ground. The moment I pulled in the parking lot they panicked, and before I even opened my car door they jumped on their scooters and bicycles and rode away. I quickly surveyed the damage. Broken flower stems, tomato plants pulled out of the ground, baby pumpkins yanked off the vine. It didn't look good, and I was furious.

I wasn't quite sure what I intended to do, but, in what might be considered a heat-of-the-moment lapse in judgment, I was suddenly driving down the road in the direction they had ridden. "What's wrong with you?" I shouted at them in my head. "This garden is not yours to destroy. Do you enjoy ruining things that your peers have worked so hard to create?" I wanted them arrested. I wanted their parents notified and for them to be grounded for the rest of their lives. I wanted them to get up in front of all 300 students at the school and apologize.

A few blocks from the garden, I spotted them sitting on the front porch stairs of a small, white house. I pulled in the driveway and rolled down my window. They all looked at me and froze. Even though I knew the answer I called out, "Were you guys just up at the garden?"

Wide-eyed and eyebrows raised they all vehemently shook their heads. I noticed that one had an untied shoelace and another had a brightly colored band-aid on his knee. It dawned on me that these vandals were just kids, maybe 9 or 10 years old. They didn't look mean or threatening (if anything, they looked scared of me, the crazy lady who had hunted them down). They certainly didn't belong in the dimly lit, damp jail cell I had created for them in my head on the drive over. They were so young. My anger subsided as I realized that the appropriate response to the vandalism was far more complicated than I had thought only moments ago. I changed techniques.

"Oh," I replied. "I thought I just saw you up there and I was hoping you could help me. Someone has been ripping out the plants. Do you know anything about that?"

They all shook their heads but otherwise didn't move a muscle. A moment later, one stood up and took a few steps forward "No, but..." he stammered. "But some of the older kids...they smoke up there a lot. We see 'em."




I thanked him for the information, and then said to all of them, "The kids who go to the school grow vegetables there. We need help protecting the garden for the kids, so it'd be cool if you could help watch it and ask people to stop wrecking the plants. People will listen to you more than they will listen to me." They nodded rapidly, still goggle-eyed and all but the one still stationary.

I strained my neck further out the window and then added, "By the way, we could really use some help at the garden too. I'm up there a lot, and if you guys ever want to help weed or water or pick vegetables, you could take some food home. I think you would be really great helpers." They nodded again and I drove away.

Three days later I was in the garden again, showing it off to two University professors who were considering encouraging their students to volunteer with the garden program the coming school year.

"Excuse me!" I heard from behind me. I turned my head and saw familiar scooters and bicycles lying next to the compost pile. Beside them were the kids from earlier that week. "Remember us?" the one who had spoken up before asked. "You said that if we helped we could take some things home."

I showed the kids how to pull weeds out by the root, and helped them identify various vegetables. We looked at different insects and replaced some labels that had gone missing. One university professor explained her favorite eggplant meal, and the kids watched her demonstrate chopping and sautéing with an imaginary knife and saucepan.

I don't know if their attitude changed after they were asked to help protect and weed the garden or if this incident was just a stroke of luck. All I know is that on that day, those kids rode home and seemed proud, their bike baskets and pockets overflowing with fresh eggplant, tomatoes and okra.

Katie Olender is the Food Systems Project Coordinator at the NorthWest Initiative, a community development non-profit organization. She is active in the local food movement, and is particularly focused on urban gardening as a means to food security for low-income communities.


2. Canada thistle management strategies for sustainable and organic farming systems
Abram J. Bicksler and John B. Masiunas 
University of Illinois 

To see great photos of the plants, seeds and learn some strategies go to manage this week go to:: <>  

Canada thistle (Cirsium arvense) is a vigorous, perennial weed that spreads by a fibrous root system or wind blown seed. Canada thistle is considered a noxious weed and has become a common problem of sustainable and organic farms. What makes Canada thistle such a problem weed? It can rapidly spread, forms dense patches, suppresses growth of crops, and is poorly controlled using standard approaches. Tillage can cut the roots into small pieces, spreading patches; tillage equipment can also carry root pieces to new sites. Mowing must start at thistle flowering and be repeated numerous times. Common winter annual cover crops (i.e. cereal rye, hairy vetch, wheat) are not present during the most susceptible growth stages of Canada thistle. 

What are the key factors to controlling Canada thistle? It is a long-day plant; flowering and seed production starts in July through August. Shoots must be killed to prevent seed production. Emerging Canada thistle seedlings will not survive shading from other plants. Grow competitive crops that rapidly close canopy. Thistle plants store sugars and other carbohydrates in their roots. The stored carbohydrates allow thistles to overwinter and emerge in the spring or after disturbance. Established Canada thistle is best controlled after emergence at the beginning of flowering, when root carbohydrate reserves are lowest. Depletion of these reserves will reduce the thistles' fitness and ability to re-grow from roots. 


Canada thistle biology: Knowing your enemy
Abram Bicksler, John Masiunas, and Dan Anderson
University of Illinois 

Canada thistle, also called creeping thistle, California thistle, and field thistle, Cirsium arvense, is a vigorous, competitive perennial weed that can establish from seed or wide-ranging, deep creeping roots. It is native to Europe, parts of North Africa, and the Middle East, and was introduced to North America in the early 17th century and has spread extensively. Canada thistle is a problem throughout the Midwestern United States on organic, sustainable and conventional farms. Cirsium species are troublesome weeds in organic cropping systems of northern Europe. 

Distinguishing Canada thistle from other thistles.  

Canada thistle can be distinguished from other thistles by three characteristics: 1) creeping horizontal lateral roots, 2) dense clonal growth, and 3) small dioecious (contain both male and female parts) flower heads (Nuzzo, 1997). Moreover, Canada thistle can be differentiated from other Cirsium and Cardus species by the following traits: 1) small dioecious flower heads <1 inch high; and 2) stems not conspicuously spiny-winged. Up to four varieties of Canada thistle have been recognized across the world, based predominantly upon their leaf morphology and pubescence. Canada thistle may change morphology in response to environmental conditions, and various ecotypes may respond differently to management practices. 

Limitations to Canada thistle spread 
Canada thistle is the most frequently declared noxious thistle in this country. Canada thistle requires a day-length of at least 14 to 16 hours for flowering to be induced, depending on ecotype. Canada thistle can survive winter temperatures of -17o F but is limited in its southerly distribution in the United States because it is less successful in hot, dry climates. It is generally a serious weed problem in areas receiving 18 to 36 inches of rainfall a year and it thrives on deep, productive well-aerated soils that do not become too warm. Optimum growth occurs at daytime temperatures of 77o F and nighttime temperatures of 59o F in soils with high nitrogen. 

Thistle flowering and seed production 
Thistles flower from July to September and sometimes into October. Seeds become viable within 8-10 days after flower opening, and an individual plant may produce from 5,000 to 40,000 seeds a year. There are conflicting reports about the number of days after flowering that a plant can be cut and still produce viable seed. Viable seed may be produced if the plant is cut down 4 days after flowering, 7 to 9 days after flowering, or 10 to 11 days after flowering. A small proportion of seeds (0.2 percent) can disperse one-half mile or more from the parent plant; thus, Canada thistle is difficult to prevent even if you are using best management practices. Canada thistle seeds float and are easily spread by flooding or in irrigation water from surface sources. Viable seeds can also be dispersed in manure. Canada thistle seeds germinate best in the top one-third inch of soil at temperatures averaging from 68o to 86o F. Approximately 60 to 90 percent of seeds germinate within one year; however, some seeds can remain dormant in the soil for up to 20 years. The deeper the seed is buried, the longer the viability. 
Seedlings are sensitive to competition for light and are unlikely to survive in competition with established plants. Once established, however, Canada thistle spread is primarily vegetative in both agricultural fields and in natural communities. Within 8 to 10 weeks of emergence, seedlings develop a taproot and spreading lateral roots that can penetrate to over 2 feet after 6 months. The horizontal spreading lateral roots can grow up to 25 feet in one season, but most patches spread at the rate of 3 to 7 feet per year. At the base of these spreading lateral roots, adventitious buds develop, rendering the plants able to regenerate if hoed or cultivated. 

Roots and vegetative reproduction
Edges of shoots can pinpoint the spread of the patch, because roots do not spread far beyond aboveground shoots. Most regeneration occurs from roots within or just below the plough layer. Most root buds are produced in the center of the Canada thistle patch, and each foot of root can average 4 to 8 root buds. The greatest Canada thistle shoot density corresponds to regions with the most underlying root biomass and adventitious root buds. The densities of adventitious root buds are three to five times greater in late summer than in spring. Cultivation stimulates the growth of horizontal roots, which increases the number of new vertical shoots borne by the chopped horizontal runners. Root fragments smaller than 1 inch in length may not re-grow, whereas root fragments 2 to 3 inches long readily regenerate shoots. Adventitious root buds are inhibited when the main shoot is present. If the main shoot is removed by tillage or mowing new shoots can emerge rapidly. In outdoor boxes, a single C. arvense plant was able to produce 26 emerged adventitious shoots, 154 adventitious root buds, and 360 feet of roots after just 18 weeks of growth. Even in systems that use herbicides, such as glyphosate, dose-response and time-course experiments have shown that the herbicide is more likely to reduce root bud numbers and secondary shoot re-growth potential than overall root biomass, still rendering Canada thistle able to regenerate.

Control strategies should aim to deplete carbohydrate reserves. Carbohydrate reserves are stored in roots rather than in shoot bases or root buds, and that these reserves can range from as low as 3 percent of root fresh weight in spring to as high as 26 percent of root fresh weight in the fall. Canada thistle carbohydrate reserves were lowest from May through August, increased in the fall, and then began decreasing in April. In growth chamber experiments, carbohydrate movements to and from the roots correspond to environmental conditions typical of fall and early spring. Moreover, environmental cues seem to supersede growth stage control of carbohydrate movement. Development of root buds is highest in the autumn when short days and moderate temperatures dominate, and root bud elongation is greatest with the long days and high temperatures of summer.

In addition to regeneration from root buds, Canada thistle shoots can grow from lateral buds at internodes on stem segments. These shoot pieces then survive if partially buried in the soil. This capacity to regenerate from root and stem fragments is particularly troublesome, as cultivation has been used for Canada thistle control. 

Canada thistle impact on crops. 
Canada thistle causes extensive crop yield losses through competition, and perhaps, allelopathy (release of inhibitory chemicals). The prickly mature foliage increases harvest difficulty and deters livestock from grazing. A density of 2 Canada thistle shoots per 1 ft2 caused yield losses of 34 percent in barley, 26 percent in canola, 36 percent in winter wheat, and 48 percent in alfalfa grown for seed. In addition to deterring livestock grazing and competing with crops, Canada thistles' shoots, roots, and leaf litter can reduce shoot and root growth of other plants through allelopathy. 

Canada thistle and other perennial weeds are very difficult to control once established, so any management strategy must also prevent their introduction and spread. Canada thistle spreads as a contaminant in crop seed, hay and packing material. Additionally, it can be spread in soil attached to vehicles and farm equipment. Thus, using clean seed, hay, and packing material and cleaning equipment are important for preventing Canada thistle from being introduced or from spreading once on a farm. 

There are a few key places in the Canada thistle life cycle that are most susceptible to management. Thistle seedlings are very sensitive to competition for light and cannot survive in dense competitive stands of established plants. Canada thistle seedlings were very sensitive to plant stand density, light, soil aeration, and soil moisture conditions. The seedling to rosette and the rosette to flowering transitions, when root food reserves are at a minimum, are particularly important times for reducing Canada thistle populations. During July to October, carbohydrate reserves accumulate in thistle roots while from May to July the carbohydrate reserves are at their lowest. The lowest root carbohydrate reserves in Canada thistle occur just before flowering. If insect (such as stem-mining weevil) feeding on Canada thistle shoots occurs just before flowering, levels of carbohydrates in the root system tend to be reduced. Moreover, if shoots are tilled between the 7-10 leaf stage (for plants originating from 5 cm and 20 cm root fragments, respectively), minimum re-growth is observed. Drought stress on Canada thistle also increases the efficacy of mechanical control. Several years of drought can reduce perennial root biomass and decrease adventitious bud production, limiting adventitious shoot production. 

In conclusion, you should focus on maximizing early spring rosette and seedling mortality. Reducing seed production and inhibiting the survival of newly shed seeds is also important, but persistence of seeds that are already in the soil seed bank has little effect on population growth because of the importance of vegetative propagation in Canada thistle patch growth. 

Selected Sources
Bond, W. and R. Turner. 2006. The biology and non-chemical control of creeping thistle (Cirsium arvense). HDRA online publication: 

Doll, J. D. 1997. Controlling Canada thistle. University of Wisconsin-Madison: North Central Regional Extension Publication. No. 218. 

Donald, W. W. 1994. The biology of Canada thistle (Cirsium arvense). Rev. Weed Sci. 6:77-101.

Doyle, S., M. Morgan, and S. K. McDonald. 2005. Organic noxious weed management. Canada thistle, Cirsium arvense Family Asteraceeae.

Graglia, E. and B. Melander. 2005. Mechanical control of Cirsium arvense in organic farming. 13th European Weed Research Society, #4600.

Graglia, E., B. Melander, and R. K. Jensen. 2006. Mechanical and cultural strategies to control Cirsium arvense in organic arable cropping systems. Weed Res. 46:304-312.

Gustavsson, A-M. D. 1997. Growth and regenerative capacity of plants of Cirsium arvense. Weed Res. 37:229-236.

Haderlie, L. C., S. Dewey, and D. Kidder. 1987. Canada thistle biology and control. University of Idaho Cooperative Extension Service: Bulletin No. 666.

 [HDRA] Henry Doubleday Research Association. 2006. Creeping Thistle Management Strategies in Organic Systems.

Hogdson, J. M. 1968. The nature, ecology, and control of Canada thistle. U.S. Department of Agriculture Technical Bulletin: 1386.McAllister, R. S. and L. C. Haderlie. 1985. Seasonal variations in Canada thistle (Cirsium arvense) root bud growth and root carbohydrate reserves. Weed Sci. 33:44-49.

Nuzzo, V. 1997. Element Stewardship Abstract for Cirsium arvense. The Nature Conservancy. Arlington, VA.Sullivan, P. 2004. Thistle control alternatives. ATTRA NCAT




Vicki Morrone

Organic Vegetable and Crop Outreach Specialist

Michigan State University

C.S. Mott Group for Sustainable Food Systems

303 Natural Resources Bldg.

East Lansing, MI 48824


517-282-3557 (cell)

517-353-3834 (fax)

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