Managing Global Resources for a Secure Future

Palmer amaranth (Amaranthus palmeri) is becoming a noxious weed in Midwestern agricultural fields. One reason for this rapid spread is that a single Palmer amaranth plant may produce over 400,000 seeds. Also, each plant only has male or female reproductive structures, leading to greater genetic diversity and the spread of herbicide-resistant genes through obligate outcrossing. Some introductions of Palmer amaranth to the upper-Midwest (especially Iowa) can be traced back to the introduction of native seed mixes that mistakenly contain Palmer seeds. The irony of the situation is that conservation programs have incentivized the use of these native seed mixes in order to promote pollinator resource establishment and health. These mixes are not tested for weed seed because many of the labels claim that the mixes are “weed free”. This is a fairly recent occurrence in that contamination did not appear until the 2016 field season. Being able to identify both noxious weeds and native plants early in the season would allow growers to get a head start on preventing catastrophe in their fields. Although there are many guides to identifying noxious weeds, there are very few native plant identification guides for land managers. This Native Plant Seedling Identification Guide documents the characteristics of 34 native plant species (29 broadleaves and 5 grasses) for identification in the first stages of growth, so that they can be distinguished from invasive plant species. The guide will be accessible on electronic devices, as well as in print, so that growers looking to conserve land can easily diagnose a swift invasion of their crop fields.