Experts from Punjab Agricultural University (PAU), Ludhiana, have cautioned fruit growers across Punjab about the adverse effects of soaring summer temperatures combined with low humidity on fruit plants. The weather conditions pose a significant threat to crops in the fruiting stage, including citrus, mango, litchi, pear, peach, and plum, potentially leading to substantial yield and quality losses if proper management practices are not adopted.
Impact on Fruit Crops
The intense heat and dry conditions can cause sunburn and sunscald on sensitive plants such as baramasi lemon, particularly on the southern side of trees. Fruit drop, leaf abscission, bark drying, fruit cracking, and scalding of branches and twigs are typical symptoms reported under such extreme weather. Young plants with underdeveloped root systems are especially vulnerable; they may die as transpiration rates spike, exacerbating water loss that the roots cannot compensate.
According to Manveen Kaur, extension specialist (fruits) at PAU, “Sensitive plants like baramasi lemon exhibit signs of sunburn and sunscald, particularly on the southern side of the trees. Baramasi lemon and litchi fruits also exhibit fruit drop and cracking because of the extreme heat.” She added that fruit drop, leaf abscission, bark drying, fruit cracking, sunburn, and scalding are typical symptoms under such circumstances.
High temperatures and low humidity also cause stem bark splitting, defoliation, and eventual drying of plants. Jagdish Kumar Arora, extension scientist (plant pathology), warned that bearing trees might suffer early fruit drop in citrus and bark splitting if not properly protected. “High yield and quality are essential for growers, and any disparity during summer could result in financial losses,” he said.
Protective Measures for Orchards
To mitigate heat stress, experts recommend irrigating fruit plants with high-quality water at intervals of 10 days. Inadequate irrigation can trigger early fruit drop in citrus and reduce fruit size and quality in peaches and plums. For early peach varieties such as Partap, Shan-i-Punjab, and Early Grande, irrigation every three to four days is necessary. Plums require watering every four to five days, while pear trees need it weekly.
Whitewashing the lower bare trunk of fruit plants is the most effective method to protect them from sun damage. This should be done in April using a mixture of 25 kg slaked lime dissolved in 100 litres of water. Adding 500 g of copper sulphate helps protect against fungal diseases, and 500 g of gum suresh (dissolved in hot water) increases durability. Experts advise repeating the whitewash in subsequent months if needed.
Windbreaks planted on the western side of orchards can shield plants from hot winds. Suitable species include eucalyptus, mango, jamun, arjun, shisham, and mulberry. For young plants, wrapping the lower trunk with old gunny bags or farm waste like paddy straw (parali) or sugarcane thrash (khori) is effective against heat injury, said Arora.
Weeds in orchards compete aggressively for nutrients and water, so mulching is recommended. Paddy straw mulch is highly efficient for controlling weeds, preserving soil moisture, regulating soil temperature, and improving organic matter and nutrient levels, according to Kaur.
Financial Risks and Expert Advice
The experts emphasized that any negligence in crop management during summer can lead to severe financial losses for growers. With proper irrigation, whitewashing, windbreaks, and mulching, farmers can protect their orchards and maintain healthy yields despite the challenging weather conditions.
