There can be many reasons for burning crop leaves.
Pest disease and nutritional deficiency are also the cause of burning of leaves.
Any type of pest and insect in the roots like nematode, cutworm, etc., cuts off the roots of the crops, due to which the leaves start falling and scorching.
One of the most common causes of leaf burns and scorching is the disease of roots, due to the infection of fungus in the roots, the roots get damaged and the leaves start burning and scorching.
Another common cause of scorching is the deficiency of nutrients in the soil and due to which the edges of the leaves start drying up.
Some pollutants are found in the air which stick on the surface of the leaves and can burn the edges of the leaf.