Biochemical changes in datepalm leaves infected by Graphiola leaf spot disease caused by Graphiola phoenicis (moug.) poit.

Four datepalm varieties (Sayar, Khalas, Halawy and Hatemi) were investigated for green pigments (chlorophyll a,b, total chlorophyll and carotenoids in leaves) at different levels of the disease severity. The per cent reduction in chlorophyll a, b, total chlorophyll and carotenoids in diseased plants were much more in highly susceptible varieties in comparison to resistant one. The disease severity and the biochemical parameters (chlorophyll and carotenoid pigments) were observed to be negatively correlated in all the varieties of datepalm.