Ecological and morphological perspectives of root rot pathogens of peanut (Arachis hypogea L.) in Pothwar region of Punjab, Pakistan

Soil borne diseases have been known as one of the significant limiting factors in peanut production. In Pakistan, little research has been done on peanut ( Arachis hypogea L.) root rot. The present survey was carried out for the assessment of disease incidence and isolation of phytopathogenic fungi causing root rot of peanut in seven tehsils of three districts of Pothwar regions viz., Chakwal (Chakwal, Talagang), Rawalpindi (Gujar khan), Attock (Attock, Jand, Pindi gheb, Fateh Jang) . Results revealed that root rot of peanut prevalence was 61.25% in surveyed area. "Two hundred and sixty-five (265)" infected roots samples were collected from 480 farmer’s fields of 79 villages during two years. During survey, it was observed that the root rot susceptible cultivar No.334 was grown in more than 70% cultivated area of peanut. The highest disease incidence was 14.2% and 15.9% in tehsil Attock, while the lowest was 8.0% and 9.6% in tehsil Gujarkhan during 2019 and 2020 respectively. A total of 104 fungal isolates were obtained from the peanut cultivation areas were Athelia rolfsii (49%) followed by Fusarium fujikuroi (29.8%) and Aspergillus terreus (21.2%). Athelia rolfsii ( CHGR2a ) had the utmost virulence followed by Fusarium fujikuroi (CHGRF5) and Aspergillus terreus (TGGR7). The pathogenicity test on peanut cultivar No.334 revealed that all the 104 isolates were pathogenic but among them 06 isolates (PGGR6, CHGR2a, ATGR3, PGGR12, TGGR7 and CHGRF5 were highly pathogenic. Disease incidence and severity values of 104 isolates varied between 15.33% to 93.3% and 13.53% to 89.53%. The disease incidence values of Athelia rolfsii, Fusarium fujikuroi and Aspergillus terreus ranged from 15.53% - 93.3%, 24.4%-88.9% and 24.4% - 84.4% while disease severity values ranged from 13.53% - 89.53%, 19.7% - 84.2% and 20.6% - 79.7% respectively.