India - Fungal ‘rust’ spreads in apple orchards after continuous rain
A widespread outbreak of fungal diseases called “rust” in this year’s apple crop is being reported in south Kashmir, more bad news for farmers who suffered losses last year, despite a good crop, because of low market rates. Horticulture experts say the inclement weather this year is the reason for outbreak of diseases. “Last year the weather remained pleasant. Except for losses to cherry due to rain, Kashmir witnessed a quality crop,” an expert based in south Kashmir said. He said the continuous rains since the month of April, coupled with hail storms, hit almost every district in the valley, damaging both horticultural and agricultural crops. Scientists posted at the Krishi Vigyan Kendra (KVK) in Balpora Shopian said that the continuous rains in recent months are the main reason why the rust diseases have afflicted apples. However, they said, the rust doesn’t affect the life of apple if it doesn’t develop cracks. An official handout prepared by the KVK in Balopra suggests that wetness from heavy dew and heavy rainfall for a long period of time, amid cold temperatures, leads to rust diseases. It also says that if frost occurs in early fruit development stage then the chances of rust are high. “Apple orchards in low-lying areas that have higher water retention capacities in Shopian district have been found to be most susceptible to rust problems,” a scientist at the KVK said. The official document says that some agricultural chemicals that contain sulphur, copper, zinc, calcium, as also the products formulated as Emulsifiable Concentrates, are known to cause rusting in apples, especially in orchards with slow drying conditions (owing to high relative humidity and poor air circulation). Spraying of fungicides along with insecticides or plant nutrients is another factor that induces rusting. Most apple growers use higher concentrations of pesticides than recommended by the agricultural university SKUAST-K. The practice of washing apple orchards with chemicals leads to a lot of active chemical ingredients accumulating on fruits, which causes rusting. Chemical rusting can develop either on the stem end when the calyx end bends downwards, or on the calyx end when it stands upright. Some chemicals like Tebuconazole, Sulphur, and copper oxychloride when sprayed at early stage of fruit development (usually before June 15) not only cause rusting but also prove to be phytotoxic to apple leaves. To contain rust diseases, scientists at the KVK recommend deep pruning of low-lying orchards, which facilitates air circulation and reduces relative humidity in the microclimate, thus creating fast drying conditions after rains and pesticide application. “Pesticide spraying should be conducted always in dry conditions. For rusting-prone orchards/ varieties, it is better to spray before heavy rains than after rains when wet conditions prevail in orchards,” one of the scientists at KVK said. After the month of June, when the temperature increases, it is better to spray pesticides early in the morning after dew evaporates. “In summer months, evening winds often bring rain showers, thereby making the spray dry slowly,” the official document says. Source - https://www.freshplaza.com
