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Sugar beet root rot at harvest in the US Intermountain West

Strausbaugh, C.A. and Gillen, A.M. (2009) Sugar beet root rot at harvest in the US Intermountain West. Canadian Journal of Plant Pathology. 31:232-240.

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Root rot in sugar beet (Beta vulgaris) causes significant losses worldwide. To assess the distribution of root
rot fungi and their relationship to bacterial root rot,commercial sugarbeet roots with rot symptoms were collected at
harvest time in the Intermountain West. Isolations for both fungi and bacteria were conducted using standard
microbiological techniques, and the root area rotted was assessed. A subset of fungal isolates was tested for
pathogenicity to sugar beet in greenhouse assays and field trials with and without manure. In the field survey of rotting
beets, the fungi most frequently associated with root rot included Fusarium spp. (Fusariumoxysporum and Fusarium
acuminatum with 24% and 15% of isolates, respectively), Geotrichum spp. (16% of isolates), Rhizoctoniasolani (15%
of isolates), and Mucor spp. (14% of isolates). However, only R.solani isolate F321 (AG-2-2IIIB) consistently caused
rot in greenhouse pathogenicity tests. In the field survey, a mean of 6% of the root tissue had rotted for individual
roots when fungi were isolated individually, whereas mean root rot was 71% and 68% when bacteria were isolated
individually or in combination with other organisms, respectively. In field trials, roots inoculated with F321 averaged
3%-5% fungal rot, whereas the percentage of root tissue with bacterial rot was 6%-78%, which supports survey
observations. Manure did not lead to root rots in the field. Traditionally, fungal root rots have been the main focus of
breeding programs; however, because of the root area rotted by lactic acid bacteria, especially Leuconostoc, these
bacteria should not be ignored in breeding efforts.

Item Type: Article
NWISRL Publication Number: 1311
Subjects: Irrigated crops > Sugarbeet
Depositing User: Users 6 not found.
Date Deposited: 30 Nov 2009 21:47
Last Modified: 17 Oct 2016 16:19
Item ID: 1334