Macro-microscopic identity, phytochemical screening and pesticidal efficacy of Blumea mollis (D.Don) Merr. aerial parts

Abstract

Blumea mollis (D.Don) Merr. is an indigenous herb used for diarrhoea and skin diseases and having antiseptic and insect repellent properties. The current study is carried out on the pharmacognostical and phytochemical evaluation and pesticidal activity of B. mollis stem and leaves. Micro-morphological profiling assists the authentication of the plant in its crude drug as well as an ingredient in formulations. As the plants possess natural insecticidal properties it can be used to control insect pests and it offers a more environmental friendly pest management rather than depending on synthetic chemicals. Macroscopic, microscopic, quantitative analysis of leaf, powder microscopy, histochemical tests and qualitative screening of phytochemicals and fingerprinting by TLC and HPTLC were done. For pesticidal efficacy of B. mollis, a preliminary field trial was conducted using pot culture experiment in a Completely Randomised Design against sucking pest complexes using chilli as a test crop. The organoleptic characters, presence of multicellular trichomes, glandular trichomes, anisocytic and anomocytic stomatal types, lignified stone cells, bordered pitted vessels, rosette crystals of calcium oxalates, etc. were noted as the diagnostic features of the plant. The spots obtained and R_f values of HPTLC can be used to differentiate B. mollis from other species and from adulterants or substitutes even in powdered form. B. mollis extract 5% proved effective in reducing the leaf curl symptom in chilli and was proved better than the commonly used botanicals such as neem oil 2%, pongamia oil 2%, Andrographis paniculata 5% and chemical pesticides like Spiromesifen 22.9% SC 96g ai/ha + Thiamethoxam 25 WG 50g ai/ha and wettable Sulfur 3g^-1. The outcomes of this research work will be supportive in the standardisation of AYUSH formulations containing B. mollis as an ingredient.