Abstract

Leaf roller (Diaphania pulverulentalis Hampson) is a serious pest of mulberry (Morus alba L.), which is the sole food for silkworm – Bombyx mori L. It attacks the tender leaves of the host causing considerable damage which alters the leaf quality. An attempt was made to know the changes in the biochemical components (free amino acids, total soluble proteins, total reducing sugars, total soluble sugars, starch and total phenols) and photosynthetic pigments (total chlorophyll, chlorophyll – a, chlorophyll – b, chlorophyll – a/b ratio and carotenoids) in six popular indigenous mulberry varieties (M₅, MR₂, Mysore local, S₃₆, S₅₄ and V₁) under infestation by leaf – roller pest. The results revealed that the biochemical components were reduced in almost all the varieties chosen. Though, there was no reduction in free amino acids in S₃₆; total soluble proteins in V₁; total reducing sugars in MR₂; total soluble sugars in S₃₆ and S₅₄; starch contents in Mysore local and S₅₄; total phenols in MR₂. The MR₂ variety showed no alteration in the free amino acids. Total chlorophyll, chlorophyll – a, and chlorophyll – b were reduced drastically in all the varieties. The chlorophyll – a/b ratio was lowered in Mysore local, S₃₆ and S₅₄. However, it was increased in M₅ and MR₂ and V₁ due to pest injury. Except Mysore local, the remaining varieties showed reduction in the carotenoid content. The alterations in biochemical components of mulberry foliage will adversely influence the health, growth and development of silkworm. This inturn results in the production of low quality silk.

Key words: Biochemical components, leaf roller, Mulberry, photosynthetic pigments.