Alterations in the biochemical components and photosynthetic pigments of mulberry (Morus Spp.) attacked by leaf – roller (Diaphania pulverulentalis) pest

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.