2001 Transplant Studies

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Plot establishment (2001)

Seeds collected from a local population of common milkweed were germinated in the laboratory in mid April, and the seedlings were transferred to the greenhouse a week later.  In late May, the plants were transplanted to the field at Western Illinois University Agronomy Farm into 48 - 100 ft2 plots with 30 inch spacing between rows.  The focus of the study was to evaluate coal dust applications on plant density so intra-row spacings of 6, 8, and 12 inches were examined.  Coal dust applications at 4 rates were also made at the time of transplanting.

First year results (2001)

Flowers and follicles formed on the first year transplanted material. However, the follicles collected in mid October yielded immature and unviable seed and floss.  A total of 4800 follicles were collected from 2880 plants for a fresh weight total of 175 pounds.  Coal dust applications appeared to have no effect on plant establishment, and an intra-row spacing of 8 inches was found to be optimal.  Stalks were harvested in late October for use in determining biomass production.

Maintenance (2002)

In early spring 2002 prior to seedling emergence, herbicide was applied to provide season long weed control.  Emergence of all plots was observed by April 25, 2002.  Thinning of plant leaves was noted in May on various plants caused by 2,4-D spray drift from neighboring areas.  The effected plants grew out of their symptoms as the season progressed.  The first flowers were noted in early July.   Plots were maintained throughout the summer with minimal weeding.  Applications of insecticides and fungicides were needed on several occasions in mid to late summer to control milkweed bugs, aphids, and black spot.


Second year results (2002)

Follicles were harvested in late September when 10% of the follicles were open.  A total of 38,500 follicles were harvested from all plots providing a fresh weight of 1035 pounds.  Of the nearly 9500 total stalks present, 7000 produced follicles.  After evaluating the three plant densities, it was determined that plant spacing effects the total follicle weight and the number of follicles per stalk.  In addition, the average stalk biomass increases with increased spacing although the number of stalks decreases.  Coal was found to have no significant effects on follicle or stalk production.


Maintenance (2003)

In advance of milkweed emergence in early spring, a preemergence herbicide was applied to all plots.  This application provided good coverage for most weed species throughout the season with remaining weeds controlled by hand cultivation or grass herbicide application.  Many volunteer seedlings from disseminated 2002 seed were observed emerging but did not survive due to the preemergence herbicide treatment.  Plants in all plots emerged by April 24 and began blooming in early July.  Spot treatments of aphids and black spot were performed as needed.

Third year results (2003)

Follicles were harvested in mid-September when 10% of the follicles were open.  A total of 38,000 follicles were harvested from all plots providing a fresh weight of 726 pounds.  Of the nearly 8500 total stalks present, 7000 produced follicles.  Analysis of the 2003 data continued to illustrate that higher concentrations of plants produce fewer, smaller follicles.  Results also supported 2002 evidence that coal treatments have no effect on follicle and stalk production. 

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Last revised: October 19, 2012