Wet Weather May Affect Management of Potato Crop

The wet June weather in Idaho provided moisture for many crops eliminating the need to irrigate. However, these same weather conditions may have a pronounced effect on the potato crop. Producers may see an increase in the incidence of diseases such as Fusarium dry rot, stem blackleg and seed piece decay, Rhizoctonia stem canker, and late blight, as well as loss of nitrogen due to excessive rain. The latter two will need the attention of potato producers.

To reduce the risk of development of Late Blight, a protectant spray should be applied before row closure followed by another application 10 to 14 days later, and then make fungicide applications based on current environmental conditions.

Additionally, producers need to carefully manage nitrogen for the remainder of the season.

The high amount of rain may have, in some fields, leached a significant quantity of the nitrogen below the potato root zone making it unavailable to the plants.

In some fields, it may be necessary to begin applying nitrogen through an irrigation system sooner than what would be done in a year with more normal rainfall. Also, be sure to closely monitor irrigation amounts to match crop-water use.