Minnesota Science
Vol. 43, No. 3
Experiment Stations Promote Disease to Improve Plants
by Larry Etkin
Minnesota's Agricultural Experiment Stations go out of their way to infect some plants with diseases that farmers usually hope stay far away from their fields. It's part of the experimental process of developing varieties tolerant to destructive and yield reducing diseases. Soybeans and sweet corn are two crops currently undergoing this strenuous test at the Southern Agricultural Experiment Station in Waseca.
The diseases are deliberately fostered to "weed out" susceptible varieties early in the testing process. Southern Experiment Station Agronomist Bill Lueschen says that just as the station promotes the growth of some weeds, it also promotes diseases to create uniform and severe conditions for their agricultural tests.
Lueschen says the station does things that an average farmer wouldn't dream of doing. "That includes practices that a farmer would call mismanagement."
The research environment requires that the adverse conditions, and indeed all soils conditions be handled uniformly so that only deliberate changes can influence the outcomes of experiments.
One particular area of deliberate "mismanagement" is testing soybeans in the same plot year after year. And compounding the problems of that situation, the plot is not tiled and purposely allowed to remain relatively moist. It's a condition highly favorable to phytothora root rot. If a proposed new introduction can survive that test with good yield, then it's likely to be a promising variety indeed.
On the Southern Experiment Station's sweet corn experimental plots, "rust" is being investigated by horticulturist Vince Fritz. He plants rows of a highly susceptible variety early, and then infects them with rust spores to get the disease established in the field before planting the experimental plots.
These types of deliberate promotion of favorable conditions for disease development
do more than just select for resistant varieties. They also provide the opportunity
for experiment station researchers to examine the lifecycles of the disease
organisms, seeking weak links that can contribute to future efforts at controlling
them.