S. KARTHICK RAJA NAMASIVAYAM, BRUCE TONY, R.S. ARVIND BHARANI AND FERNANDO RUSSELL RAJ
Abstract
Increased awareness of the environmental damage caused by continued use of conventional synthetic herbicides has aroused great interest in biodegradable, selective and environment friendly bio herbicides. Microbial metabolites have become the focus of attention of researchers searching for natural product alternatives to conventional herbicides. In the present study, herbicidal metabolites were extracted from culture free supernatant of fungi Fusarium oxysporum isolated from soil and the herbicidal activity was evaluated against Ninidam theenjan under in vitro condition. For the metabolites production,fungi was grown in phytotoxin production media under optimum condition, the collected filtrate was extracted with ethyl acetate. Possible composition of bioactive compounds present in the ethyl acetate was studied by gas chromatography equipped with mass spectrometry (GCMS) Further the extracted metabolites were loaded with chitosan nanoparticles. Effect of temperature on phytotoxicity was also studied. Phytotoxixcity study reveals both the free and nanoparticles showed distinct phytotoxic effect against the tested weed and the activity was retained at 70oC. The present study suggests the possible utilization of F. oxysporum both free and chitosan nanoparticles incorporated metabolites as the herbicidal agent against Ninidam theenjan.