2002 Transplant Studies

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Plot Establishment (2002)

Seeds from a local milkweed population were germinated in the laboratory and transferred to the greenhouse in mid-April.  A preemergence herbicide was applied and incorporated prior to manually transplanting the 50 - 100 ft plots in late May 2002.  The within row plant distance was held constant at 8 inches.  Plot maintenance was done manually and pesticides were applied as needed to control aphids.



Planting Density Trials

Milkweed transplants were planted at 3 inter-row spacings (7.5, 15, and 30 inches) to evaluate plant density and its effect on plant establishment and follicle production.  Three transplant initiation dates were also used to determine whether first year follicle production is influenced by date of seed germination.  Seed was started March 15, April 1, and April 15.


Nitrogen Evaluations

Nitrogen at rates of 50 and 100 pounds per acre was applied to a number of  transplant plots to determine its effect on follicle production.  All nitrogen plots were planted at 15 inch inter-row spacing.



Topping Experiments

A selection of additional plots were kept pruned back to an 18 inch height to evaluate the effects of first year topping on second year follicle production.  All topping plots were planted at 15 inch inter-row spacing.

First Year Results (2002)

A small number of plants produced follicles in the first year, but seed and floss was immature.  All stalks were removed at the end of the season. 

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.   Plants in all plots emerged by April 24 and began blooming in early July.  Nitrogen was reapplied to the nitrogen evaluation plots on May 16.  No additional pruning was performed on the topping experiments this season.  Spot treatments of aphids and black spot were performed as needed.

Second Year Results (2003)

Follicles were harvested in mid-September when 10% of the follicles were open.  A total fresh weight of 450 pounds from 22,200 follicles was harvested from all the plots combined.  Nearly 4900 stalks of the 9950 stalks present  produced viable follicles.  Results of the planting density trials examining 3 inter-row spacings show that higher plant concentrations have an adverse effect on follicle production.  Evaluation of the 3 planting dates demonstrated that the April 1 date  produced the healthiest plants at transplant time and again in 2003.  In addition, topping the milkweed did not influence follicle production in the second year.

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Last revised: October 19, 2012