Assessment of the Bioweedicidal effects of Alternaria alternata Metabolites against Parthenium species

Abstract

Three different isolates of Alternaria alternata were isolated from three different weed species viz. Eichhornia sp., Achyranthes sp. and Parthenium sp. All the isolates were checked for production of secondary metabolites by performing TLC analyses of their respective culture filtrates. Results of TLC analyses revealed production of secondary metabolites by all the isolates. A very considerable reduction in the germination of the Parthenium seeds was observed following treatment with different culture filtrates at their full strength as well as half strength. The observed reduction in germination was 27% by isolate no. 1, 44% by isolate no. 2 and 37% by isolate no. 3 using their full strength culture filtrates respectively. When half strength culture filtrate was used the reduction in germinationwas by 17%, 20% and 27% by the three isolates respectively. The root length of the germinated seedlings was reduced by 51%, 53% and 42% following treatment with the full strength culture filtrate of the three isolates 1, 2 and 3 respectively while in case of half strength culture filtrate of the three isolates 1, 2 and 3 the root length got reduced by 23%, 22% and 19% respectively. The shoot lengths of the germinated seedlings was reduced by 45%, 41% and 48% following treatment with the full strength culture filtrate of the three isolates 1, 2 and 3 respectively while in case of half strength culture filtrate of the three isolates 1, 2 and 3 reduced the shoot length by 20%, 15% and 22% respectively. These findings show the potentials of Alternaria alternata isolates and their metabolites for bioweedicidal properties against Parthenium sp.