Some epidemiological aspects of strawberry angular leaf spot in Egypt

Abstract

In this study, various epidemiological aspects of strawberry angular leaf spot caused by Xanthomonas fragariae including the disease distribution and intensity in strawberry fields, incidence of X. fragariae on cooled stored transplants, aggressiveness of numerous Egyptian strains of X. fragariae, and cultivars reaction were investigated under Egyptian conditions. Among four governorates surveyed in 2007 and 2009 growing seasons, the disease occurred in Beheira and Qalyubia and did not occurre in Sharqia and Ismailia. In Qalyubia governorate, the number of fields that exhibited the angular leaf spot disease in both seasons was generally fewer than those in Beheira governorate. Disease intensity was higher in Beheira than Qalyubia during both seasons and was higher in 2009 than 2007 in both governorates. Among all surveyed localities, Markaz Bader had the highest disease intensity whereas Al-Deer locality had the lowest. X. fragariae was detected in plants stored in cold storage facilities at Beheira and Qalyubia governorates and the pathogen was more frequently isolatedion incidence was higher in Beheira than Qalyubia. Little variation was observed among the 15 local strains of X. fragariae with regard to their virulence and none of these strains was exceptionally virulent. There was no resistant cultivars among the 14 strawberry cultivars tested. All cultivars ranged from moderate to highly susceptible. The highest susceptible cultivars were Camarosa and Sweet Charlie.