Scientists blame excessive use of pesticides for apple disease

Farm scientists from Dr YS Parmar University of Horticulture and Forestry, Nauni, have attributed the rising incidence of disease in apple orchards across Shimla district to the excessive and unregulated use of chemical fertilisers and the harmful mixing of pesticides, fungicides, micronutrients, and growth regulators. This practice, strongly discouraged by experts, has been linked to the spread of Alternaria leaf blotch and blight, especially with the onset of the monsoon.

Teams from the university, including plant pathologists, entomologists and fruit scientists, conducted field visits and awareness drives across the district. They observed that several orchards were showing signs of disease, varying in severity depending on the location. A key concern was the widespread use of non-recommended agrochemicals and the failure to follow proper spray schedules.

Farmers were advised to strictly adhere to recommended agricultural practices, including avoiding the mixing of incompatible chemicals, using only approved agrochemical brands, following a structured spray schedule and rotating systemic and non-systemic fungicides to prevent resistance. Maintaining proper canopy spacing, avoiding humid microclimates—particularly on the shady side of trees—and keeping branches from intermingling with shrubs were also emphasised.

For mildly affected areas, the scientists recommended protectant fungicides such as Propineb, Zineb, Metiram 70% WG, or Ziram (600 g per 200 L water). In severely affected areas, they advised combi fungicides combining systemic and non-systemic action, including Hexaconazole + Zineb (500 g/200 L), Fluopyram + Tebuconazole (126 ml/200 L), Carbendazim + Flusilazole (160 ml/200 L), and Mancozeb + Pyraclostrobin (700 g/200 L).

The initiative is part of a broader campaign to raise awareness among apple and stone fruit growers about Alternaria and other foliar diseases. Five expert teams from the university’s main campus, RHRTS Mashobra, and Krishi Vigyan Kendras (KVKs) in Solan and Shimla have been mobilised for this task.

Field visits will continue in locations such as Jubbal, Chirgaon, Theog, and Narkanda. Meanwhile, RHRTS Bajaura (Kullu), KVK Chamba, and KVK Kinnaur reported negligible impact of Alternaria in their regions.

Himachal Tribune