Characterization of pathogens and foliar disease interactions impacting sugar beet storage

Authors: HENDERSHOT, CARLY - Michigan State University; BLOOMINGDALE, CHRIS - Michigan State University; Goodwill, Tom; Hanson, Linda; WILBUR, JAIME - Michigan State University

Submitted to: Journal of Sugar Beet Research
Publication Type: Abstract Only
Publication Acceptance Date: 1/1/2021
Publication Date: 2/28/2021
Citation: Hendershot, C.N., Bloomingdale, C., Goodwill, T.R., Hanson, L.E., Wilbur, J.F. 2021. Characterization of pathogens and foliar disease interactions impacting sugar beet storage [abstract]. Journal of Sugar Beet Research. 58:95.

Interpretive Summary:

Technical Abstract: The US sugar beet production has a market value of over $5 billion. In Michigan, sugar beets (Beta vulgaris) are stored for up to 200 days post-harvest while awaiting processing. During this storage period there are several factors that cause the beets to rot, reducing the sugar content and overall profit. In addition to root degradation, fungal mycelium and pectinase byproducts clog filters and slow the extraction process. Michigan Sugar estimates that delaying onset of storage rot one month could save the industry $1 million per year. Proper identification and characterization of the pathogens affecting stored beets will allow for better targeting disease management. In addition to organisms that directly colonize the beet root, it is not well understood how foliar disease in the field will affect the storability of the beet. Cercospora leaf spot (CLS) is the most damaging and widespread foliar disease of sugar beets. To investigate the impact CLS has on pathogens colonizing the beet root post-harvest trials will compare rates of root rot by Fusarium graminearum, Botrytis cinerea, Penicillium vulpinum, and Phoma betae in beets with high or low in-season CLS severity. Beet root rot will be rated monthly between harvest and 120 days into storage. This study will also examine varietal effect on rate of rot using CLS resistant and susceptible varieties. In 2019, a preliminary screening was conducted at harvest on roots selected arbitrarily by agronomists in Bay, Saginaw, Tuscola, Huron, and Sanilac counties. At harvest 38% of roots were colonized with Rhizoctonia sp., 40% with Fusarium spp., 16% with Geotrichum sp., and 6% with Trichoderma spp. (n=85 beet roots). In 2019, storage samples with advanced stages of root rot were obtained five months into the storage period from Kinde and Sebewaing locations. Aspergillus sp., Alternaria sp., Botrytis sp., Fusarium sp., and Penicillium sp. were identified from symptomatic samples. Isolated organisms will be further characterized and may be used in future storage trials. Identification and characterization of post-harvest pathogens affecting sugar beets as well as studies of the effects of CLS on storability will help further inform beet storage management.