UW Extension Ag Weather

Potato Image from Fir0002/Flagstaffotos

Image licensed under the GNU Free Documentation License by Fir0002/Flagstaffotos

Potato Development

Our potato Pday model lets you predict plant development of this pest to better manage production.

Potato Pests

For information on potato pests such as the Colorado Potato Beetle, see our degree-day calculator page.

Potato Development


We're sorry to note that these products were defunded in April of 2015; they continued working for over a year, but as of Mid-June the old servers finally gave up. The team at agweather.cals.wisc.edu is working to restore as many of them as they can, but their funding is limited too. Check back on their site to see what they've got working. It has been a pleasure serving you.


Download The Image in Black and White

P-Days are the unit of thermal time used in a number of University of Wisconsin-Extension potato management products. To learn more about these products, visit UW's Integrated Pest Management site.

Below you will find P-Day maps for:

  1. May 15 to the present
  2. May 1 to May 14
  3. May 7 to May 14
You can correct P-Day values from the May 15 starting date map (Map 1) for your planting date by adding additional P-Days from Map 2 or Map 3 as appropriate.

Earlier P-Day Maps (available mid-May)