Disease status of almond blight in Kashmir and Morpho-physiological studies on its casual pathogen Cryptosporiopsis carticola

Orchard survey conducted in two major almond growing districts of Kashmir valley during 2002and 2003 revealed the prevalence of almond blight disease in both the districts, with highest disease incidence in district Budgam. The average disease incidence and intensity of almond blight in Kashmir was 25.5 and 12.8%, respectively. The disease initiated as minute water-soaked spots at the base of leaf petioles in June, extended along the axis of twig at a faster rate and attained an average length of 20.2 x 1.5 cm in September. The lesion not only increased in length but also griddled the twig at the point of initiation resulting in complete twig blightening above the girdled area. The causal fungus was identified as Cryptosporiopsis carticola stage of Pezicula corticola (Jorgenson) Nannf. which is a new report from Kashmir. The pathogen exhibited optimum growth at 25±1°C on malt extract agar having pH 5.0. However, best sporulation was achieved in potato dextrose agar followed by corn meal agar medium. The mycelial growth rate was initially higher in PDA but later on in almond-infusion agar medium. Malt extract medium showed consistent growth through out the study. Recovery of partially blighted twigs from disease and absence of any viable over-wintered mycelium revealed annual nature of disease and, therefore disease requires fresh infection year after year for its spread.