ABSTRACT
Net blotch of barley (Hordeum vulgare L.) consists of two closely related but separate diseases that occur worldwide in barley growing areas. These are the net form of net blotch (NFNB), caused by Pyrenophora teres f. teres (PTT), and the spot form of net blotch (SFNB), caused by P. teres f. maculata (PTM) (Smedegård-Petersen 1971). As their names suggest, the net form has characteristic netting symptoms resulting from lesions along leaf veins with longitudinal and transverse dark striations. The spot form shows ovoid to round lesions often surrounded by a chlorotic border (Fig. 1).
