Potato Blackleg in Jordan Reaction of Some Potato Cultivars to the Infection and Effect of Planting Date
2003
Al-Masa'deh, M. | Khlaif, H. (Jordan Univ., Amman (Jordan) Faculty of Agriculture)
Survey of potato fields indicated that blackleg disease occurred in different potato growing areas in the Jordan Valley as well as in the uplands. Fifty bacterial isolates were isolated from different potato samples suspected to be infected with blackleg, collected from different potato growing areas, were biochemically, physiologically, and pathogenically tested. The results of the different tests indicated that the causal agents of the blackleg in Jordan is Erwinia carotovora pv. atroseptica (van hall) dye. Results of field experiments revealed that the disease occurred on two planting dates, but with high incidence on the first planting date in comparison to the incidence of the disease on the second planting date, which could be correlated to the average soil temperature. This was around 16.5 on the first and 22°C on the second planting date, and the lower temperature favored blackleg development. The five tested potato cultivars were found to be susceptible to blackleg either to natural infection in the field on both planting dates, or to the artificial inoculation in the lab with Eca suspension. The response of the five tested cultivars was found to follow the same pattern either in the field or in the lab, with Draga being the least and Spunta the most susceptible cultivar
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