Impact of Leaf Roller (Diaphania pulverulentalis) Infestation on the Mineral Nutrition of Mulberry (Morus spp.) Varieties

Mulberry (Morus spp.) foliage is the exclusive food for the silkworm, Bombyx mori L. The healthy growth of silkworm and its economic traits such as larval, cocoon and grainage parameters are known to be influenced largely by the nutritional status of the leaves fed to them. The mineral elements comprise major part of nutritional quality of mulberry leaves, which may alter due to injury caused by pests and diseases. Therefore, an attempt was made to know the variations in the mineral nutrition of mulberry foliage under leaf roller (Diaphania pulverulentalis) infestation. Six macro (nitrogen, phosphorus, potassium, calcium, magnesium and sulphur) and seven micro nutrients (zinc, iron, manganese, copper, boron, molybdenum and chloride) were analysed in six popular indigenous mulberry varieties (M₅, MR₂, Mysore local, S₃₆, S₅₄ and V₁). The nutrients decreased in the pest - infested leaves of almost all the varieties except nitrogen and potassium in Mysore local and V₁, phosphorus in S₃₆ and V₁, magnesium in M₅ and Mysore local and sulphur in V₁, zinc in S₃₆ and S₅₄, boron in S₃₆ and chloride in Mysore local varieties where they were increased. However, no changes were observed in the contents of nitrogen and potassium in MR₂, phosphorus in MR₂ and Mysore local, calcium in M₅, S₃₆ and V₁, magnesium in S₅₄ and V₁ and sulphur in M₅, S₃₆ and S₅₄, zinc in V₁, iron in M₅, Mysore local and V₁, manganese in M₅, copper in S₅₄ and V₁, boron in M₅, MR₂, Mysore local and V₁, molybdenum in M₅, MR₂, S₅₄ and V₁ and chloride in M₅, S₅₄ and V₁ varieties. These variations in the mineral nutrients results in the nutritional inferiority of mulberry leaves. Feeding such leaves will affect the growth and development of silkworms which in turn adversely brings down the quality of silk production.