EFFECT OF SPIRULINA PLATENSIS EXTRACTS ON EARTHWORM, EISENIA FETIDA

Abstract

Earthworms are farmer‟s friend, which play an important role in the soil ecosystem. Hence, application of any agrochemical, biopesticides and any other biological products for crop protection needs to be evaluated for its effectiveness (toxicity) towards Earthworm. In the present experiment, three types of Spirulina platensis extracts were tested against earthworm, Eisenia fetida in a 14 day acute earthworm toxicity study. The Spirulina extracts were prepared using solvents, Acetone (100%), 95% Ethanol and 95% Methanol respectively. The concentrations of the extracts were prepared using in deionised water and mixed with artificial soil and incubated under controlled environmental conditions (at 20±2°C temperature in 400-800 Lux light intensity) for 14 days. Four replicates were maintained per treatment. Concurrent solvent controls and a control with deionised water were maintained for comparison. On day 14, the biomass change and the mortality of the earthworms were determined to assess the LC50 (Lethal Concentration) and the NOEC (No Observed Effect Concentration) (related to biomass change and mortality) of the tested concentrations of the extracts. The study results revealed that all the extracts are safer to earthworms in the tested concentration. Hence, it is concluded that the Spirulina extracts are non-toxic to earthworms in artificial soil under laboratory conditions.