Curvularia spicifera, A PARASITE OF THE FUNGAL COMPLEX OF ROOT ROT OF WHEAT AND BARLEY IN MOROCCO

Surveys were carried out in wheat (durum wheat and soft wheat) and barley fields in April-May 2017 in northwestern Morocco allowed the isolation of a species of the Curvularia genus from the characteristic necrotic lesions of the root rot of wheat and barley. This fungus was isolated either in the presence of Bipolaris sorokiniana or among a variable Fusarium complex. It has been identified as Curvularia spicifera. Koch's postulate was verified by inoculating six isolates of this fungus into varieties of wheat (durum wheat and soft wheat) and barley. All of these isolates induced necrotic lesions on the roots and leaves of seedlings from the inoculated grain. Re-isolations of the pathogen from these lesions were positive. Severity indices can reach 90% in hard and soft wheat and 88% in barley, with incidences of the disease ranging from 50% to 96%. Sporulation at the root and leaf lesions of wheat plants is important; it varies between 6.2 106 and 1.9 106 conidia / cm2 in durum wheat and between 6.11 106 and 4.88 106 conidia / cm2 in common wheat. On the other hand, it varies between 5.8 106 and 0.93 106 conidia / cm2 in barley. To our knowledge, this is the first report of root rot caused by Curvularia spicifera on wheat and barley in Morocco. The pathogen will probably become important and take up more of the other known diseases of cereals.