Survey and Characterization of Strawberry Cultivars Susceptibility to Crown and Root Rot Diseases in Ismailia Governorate, Egypt

Abstract

Soil-borne fungi of strawberry are distributed and infected the plants under different soils moisture,. High incidence of crown rots of strawberries caused by Macrophomina phaseolina and Colletotrichum acutatum has been observed and isolated in major strawberry production districts in Ismailia Governorate. Pathogenicity test and susceptibility of different strawberry cultivars were done. Two fungiunder study were proved.Both fungi were found as virulent pathogens and caused pathogenic effect to different tested strawberry cultivars in vivo.Festival was the most susceptible cv. followed by N-70 and Gavuta cvs. However, Camarosa cv. was the lowest susceptible to C. acutatum while the other cultivars (Sweet Charlie and Fortuna) were similar and showed moderate susceptibility to foliar inoculation with the pathogens ,respectively.Colletotrichum acutatum was less virulent than M. phaseolina either in disease incidence (DI%) or disease severity (DS%).Studying the host range of the two pathogens revealed that cotton, sesame, soybean, water melon and sunflower showed positive reactions and respond to the artificial inoculation with M. phaseolina (the causal of charcoal rot disease) with percentages of disease incidence ranged from 50 -80% , respectively. On the other hand,all the testedelevin hosts showed negative response without any disease symptoms when it artificially inoculated with C. acutatum. Survival of both M. phaseolina and C. acutatum inocula buried in depths of 0.0, 5, 10 and 15 cm in field soil were recovered and keep its viabilitytill 120 days sthenstarted to decrease as it reached 60and80% after180days for the two pathogens under study, respectively.