Herbicides and Milkweeds

Herbicides are killing milkweed plants. Farmers often spray the herbicides around their crops to get rid of weeds that can compete for resources with their crop plants. Here's why this is really bad: monarchs seem to prefer milkweed plants that are in or close to agricultural fields.

A study done in 2001 found that more than 80% of the monarchs in the Midwest were feeding on milkweed plants in agricultural fields. Since 2001, milkweed plants have basically been eliminated from agricultural fields because of herbicides and because of planting more corn and soybeans that are genetically modified to be resistant to the herbicides. The loss of milkweed plants has caused a decline in monarch population.

Agricultural fields is just one important habitat that monarchs and milkweeds have. The other important habitat is roadside areas. It is very important that transportation department officials be informed about how herbicides and mowing practices can be harmful to milkweed plants and the monarchs.  

Kniss, A. (2014, February 10). Are herbicides responsible for the decline in Monarch butterflies? Retrieved April 3, 2016, from http://weedcontrolfreaks.com/2014/02/are-herbicides-responsible-for-the-decline-in-monarch-butterflies/

Pleasants, J. (2014, June 6). Monarch Butterflies under Threat from Rising Herbicide Use. Retrieved April 3, 2016, from http://www.scientificamerican.com/article/monarch-butterflies-under-threat-from-rising-herbicide-use/