Nora Olsen, Professor and Extension Potato Specialist at the Department of Plant Sciences, University of Idaho, presented on the factors that impact development of bruises during the online annual Idaho Potato Conference last month.
Prof Olsen started out by saying that her and her colleagues’ experience evaluating quality losses over the past several years, points to the primary association with either a direct impact, blackspot bruise or shadow bruise, or an indirect impact – meaning that the direct impact caused subsequent loss due to soft rot, dry rot and potentially even pressure bruise.
“Having a strong association prompted us to focus our research efforts at these direct impacts of shatter bruise and blackspot bruise,” she said. Initially, there must be a physical impact for bruise to occur, emphasising that minimising of drop heights, padding equipment, and raising stingers are all part of the equation to minimise that physical impact.
“But we must move potatoes around on a lot of pieces of equipment, and physical impact is unfortunately inevitable,” Nora said. “One option to identify those physical impact risks is to use some sort of detection method, such as using an impact recording device as a management tool which allows you to identify the force and velocity of a physical impact, and then allows you to modify equipment and listen lessen the risk for bruise.”
“As an example, we dropped the impact recording device on four different materials. A max gram of 80 to 100 is about the threshold where a bruise may occur. If you drop a potato onto a potato, you may not see a bruise until a drop of 14 inches, which is why the recommendation is to keep chains and belts full with potatoes. But if you drop it on unpadded chain, it only takes about a two inch drop to cause a bruise.”
Nora noted that overall it is not only the drop to be concerned with, but the material it drops onto that can cause a bruise. “That is one reason you’ll hear about padding equipment, and looking for any area that may create a greater risk for fiscal impact.
“Yes, you need a physical impact to cause a bruise. But we also know that the potato will vary in response to that physical impact based upon its physical and physiological characteristics. It becomes a very complex matrix in which several components will impact susceptibility, and some may even contradict the other.”
Nora says she and her colleagues are collaborating with multiple experts in the tri state area to better understand the practices associated with blackspot bruce susceptibility.
“Specifically, we are addressing maturity nitrogen management, soil health, and measuring these tuber biochemical components that may help us better understand about the potato response and identify useful measurements for identifying the risk for bruise.”
Watch the 20 minute presentation below, as well as on YouTube here.
Source: University of Idaho
Photo: University of Idaho Extension. Monitoring Tools for a Potato Bruise Prevention Program