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First Report and Virulence Evaluation of Erwinia carotovora subsp. betavasculorum on Sugarbeet in Montana

Zidack, Nina K., Jacobsen, Barry J.
Plant health progress 2001 v.2 no.1
Beta vulgaris subsp. vulgaris, sugar beet, bacterial diseases of plants, Pectobacterium carotovorum subsp. betavasculorum, necrosis, new geographic records, virulence, air temperature, disease control, fertilizer application, nitrogen fertilizers, row spacing, planting date, Montana
Bacterial vascular necrosis of sugarbeet caused by Erwinia carotovora subsp. betavasculorum (Ecb) was identified in the Bighorn Valley near Hardin, Montana in 1998 and was observed at low incidence in the Yellowstone River Valley in 1999 and 2000. Until now, this disease had not been reported in Montana. Experiments were performed comparing the Montana isolate with isolates of Ecb from California for virulence against the California standards for sugarbeet resistance to Ecb. In our experiments, the Montana isolate was more virulent than all of the other isolates when plants were inoculated by injecting Ecb into the petiole. Variety USH11 was the most resistant and the most susceptible variety was Beta 4430, which has been shown to be resistant to CA isolates in other tests. In temperature experiments, sugarbeets became severely diseased at temperatures ranging from 20 to 28°C, but severe beet (root) necrosis only developed at 24 and 28°C. Montana farmers and growers in northern sugarbeet-growing areas should be aware of the potential for this disease during warm summers. Also, it is clear from these results that the Montana isolate should be used to screen varieties for resistance for Montana growers and that the California isolates are not suitable for this purpose. Disease management may be accomplished with resistant varieties, avoiding injuries to plants, minimal rates of nitrogen fertilizer, early planting, and plant spacings of 15 to 20 cm between plants (2).