Alternaria disease spreads in HP Apple belt, Nauni university issues fresh advisory
Shimla, July 21
Amid continuous monsoon rains, Alternaria leaf spot has emerged as a growing concern in several apple-growing areas of Himachal Pradesh, prompting Dr YS Parmar University of Horticulture and Forestry (UHF), Nauni, to issue a fresh advisory urging growers to immediately adopt scientific disease management practices.
The Department of Plant Pathology at UHF said that prolonged rainfall, high humidity and wet conditions have created an ideal environment for the rapid spread of Alternaria leaf spot, Marssonina leaf blotch, leaf blight and other soil-borne diseases.
The advisory assumes significance as horticulture experts have warned that unchecked spread of Alternaria could affect both fruit quality and apple production this season.
According to experts, the disease is spreading more rapidly in lower apple-growing areas where temperatures remain relatively high and humidity is excessive. Infected trees shed leaves prematurely, reducing their photosynthetic activity.
This directly affects fruit size, colour and overall yield, causing financial losses to growers. Farmers have reported that the disease has become more severe over the past three to four years.
The university has advised orchardists to remove weeds from orchards and regularly monitor trees for symptoms of Alternaria, Marssonina leaf blotch, white root rot and collar rot.
Growers have been asked to strictly follow the fungicide spray schedule recommended by the Directorate of Horticulture and UHF.
Protective sprays of metiram have been recommended, while orchards with severe infection should use alternate sprays of recommended fungicides such as Lustre 5% SE, Cabrio Top 60WG, Shamir, Luna Experience and Avtaar in prescribed doses.
For white root rot, the advisory recommends drenching tree basins with carbendazim three to four times during the rainy season, while mancozeb has been suggested for collar rot management.
The university has also advised spraying Cuprofix DISPRESS within 24 hours after harvest to manage silver leaf canker.
The advisory cautions growers against mixing pesticides with micronutrients, growth regulators or other chemicals, as this may lead to phytotoxicity and crop damage.
Horticulture Minister Jagat Singh Negi said the department has constituted monitoring teams to assess the disease situation in apple orchards.
He appealed to growers to strictly follow the recommended spray schedule and scientific management practices to minimise losses.
Experts have also pointed out that excessive and unscientific spraying, indiscriminate mixing of chemicals and imbalanced fertiliser use can increase the susceptibility of apple trees to disease.
Scientists of Nauni University have already conducted awareness campaigns in major apple-growing regions and urged farmers to promptly report disease symptoms with photographs to the university for expert guidance and timely intervention.
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