Content area
Full text
Abstract
In vitro inhibition of 16 aroma chemicals was studied against five seed-borne fungal pathogens in the concentration range of 100 to 8000 ppm: Drechslern sorokiniana (Sacc.) Subram. et Jain, Phomompsis sojae Leh., Fusarium solani (Mart.) Sacc., Colletotrichum graminicola (Ces.) Wilson and Macrophomina phaseolina (Tassi) Goid. Minimum inhibitory concentration (MIC) was computed for each chemical against each fungus. All the chemicals had shown dose-dependent inhibitory effect of mycelial growth. Eugenol, methyl eugenol, citral, 2-phenethyl alcohol, 2-phenethyl acetate and 2-phenethyl propionate were found to be highly effective against all the test fungi with MIC values of 270 to 1704 ppm and potentially hold promise in plant disease management and plant quarantine.
Key Word Index
Antifungal activity, seed-borne fungi, Drechslera sorokiniana, Phomompsis sojae, Fusariumsolani, Colletotrichum graminicola, Macrophomina phaseolina, aroma chemicals, eugenol, citral, 2-phenethyl propionate.
Introduction
Colossal crop yield losses occur worldwide, in spite of intensive plant protection efforts. Approximately one third of the losses are attributed to plant pathogenic microorganisms including fungi, bacteria and viruses. Although the application of fungicidal treatment is reported to reduce seed-infection and improve seed germination (1,2), the development of resistance to fungicides in fungal populations is, however, of particular importance (3). To avoid this, new strategies in fungicide use and disease management must be developed and thus the need to identify new chemicals as potent fungicides is imperative. Hence, efforts are being made to find alternatives that are safe and eco-friendly. In this direction, the use of biotic and abiotic agents find their due importance. Extracts/products from medicinal plants and bacterial and fungal strains are note-worthy, and some of the phytochemicals are also known to induce systemic activated resistance in plants against infection (4). Many workers have recommended the use of aroma chemicals in the control of mold infestation during storage (5-8). In the present study, 16 aroma chemicals were evaluated for their antifungal properties against five fungi namely, Colletotrichum graminicola (Ces.) Wils., Drechslera sorokiniana (Sacc.) Subram. et Jain, Fusarium solani (Mart.) Sacc., Macrophominaphaseolina (Tassi) Goid. and Phomopsis sojae Leh. These fungi were reported to be seed-borne on a wide host range (9) and have also been intercepted during the quarantine processing of some new crops and exotic germplasm (10,11).
Experimental
Isolation of seed-borne fungi: The fungal colonies of D....