In addition to a general warming trend, growers across the Commonwealth are witnessing a more variable climate for crop production. That’s according to Dave Van Sanford, a plant and soil science professor at the University of Kentucky. His department was recently awarded a $120 thousand dollar grant from the USDA to observe resistant wheat varieties in warming environments.
“This particular project concerns resistance to a disease that is very problematic in this part of the country called, “head scab” or fusarium head blight. The main thrust of the study is to determine whether the resistance genes we have found to be effective so far will also be effective in a warmed environment,” says Van Sanford.
The warming simulation is achieved by burying heating cables in the soil, which are then used to elevate the temperature of the root zone between 3-5 degrees Celsius during the course of the season.
“We are inoculating a number of different breeding lines and cultivars with a suspension of fungal spores that will cause this disease to take hold and then we are assessing the effectiveness of the genes under these environments,” says Van Sanford.
Almost all of Kentucky wheat is planted after corn in the fall. According to Van Sanford this particular fungus thrives in corn stubble “so the inoculum is always present, so really our crop is sort of always at risk of this disease.”
Certain environmental conditions need to be met for the fungus to grow. “You need to have abundant moisture at flowering and a susceptible host, so if you have those things along with the abundant inoculum then you are going to have head scab,” says Van Sanford.
The two fungicides of choice, Caramba and Prosaro, applied with a wheat variety that has some resistance to head scab is currently the best method to minimize the disease.
“There are FDA advisory limits, wheat that is highly infected and has toxin levels above 2 parts per million can not be milled into flour. A lot of times what will happen is that grain will be blended, so that’s a really big issue associated with the disease,” says Van Sanford.
So far this year, Van Sanford says “we have dodged a bullet because there wasn’t a lot of moisture when the wheat was flowering.” He says no one knows for sure, but he is “trusting his gut” that the fungus won’t be a problem.
