Impact of inoculum distance on initiation and progress of apple scab [Venturia inaequalis (Cke.) Wint.] infection Qazi Nissar A.2,*, Ahmad Khursheed1, Beig M.A.1, Munshi N.A.1, Khan N. A.1 1Division of Plant Pathology, S.K. University of Agricultural Science and Technology of Kashmir, Shalimar, Srinagar-191 121, (J&K). 2Division of Post Harvest Technology, S.K. University of Agricultural Science and Technology of Kashmir, Shalimar, Srinagar-191 121, (J&K). *E-mail: qazishaheen@gmail.com
Abstract Sanitated apple seedlings cv. ‘Red Delicious’ were planted at isolation distance of 0, 60, 90 and 120 m from the primary source of Venturia inaequalis inoculum, i.e. from the established scab-infected apple trees having overwintered leaves in tact, to study the impact of inoculum distance on the spread and progress of infection. A marked delay in disease appearance was observed with increase in isolation distance from source. All the isolation distances resulted in significant reduction in spread and progress of V. inaequalis infection compared to that noticed at or nearer to inoculum source throughout the growing season. Maximum reduction of 74.1, 66.9 and 50.8% in overall progress of disease was observed at 120 m isolation distance during petal fall, fruit-let and pre-harvest stages. The reduction at 90 m isolation distance was 55.3, 42.4 and 34.7% but least (16.7, 30.6 and 14.9%) at 60 m isolation distance. The study revealed that spray programme can be delayed by adopting proper sanitation measures and by maintaining isolation distance of at least 90 m away from any inoculum source. Top Key words Apple phenology, ascospores, overwintered leaves, primary inoculum, Venturia inaequalis. Top |