Antifungal property of chemical elicitors and induction of systemic required resistance for the control of rice blast caused by Pyricularia grisea Sacc.
2012
Piamonte, R.T. | Borines, L.M.
Induction of systemic acquired resistance (SAR) is a promising strategy in managing plant diseases. This study was conducted to evaluate the ability of selected chemicals to induce SAR for rice blast control at varying concentration, spray interval, and number of applications. Benzothiadiazole (BTH), salicylic acid, acetylsalicylic acid (ASA), chitosan, gamma amino butyric acid (GABA) silicon dioxide (SiO2), beta amino butyric acid (BABA), thiamine, linoleic acid, acetic acid, and mancozeb were applied as sprays and treated plants were challenged by P. grisea inoculation. Disease severity ratings, plant height, days to flowering, number of surviving plants and yield data were compared between treatments. All the chemicals tested produced lower disease severity in rice and higher yields which are comparable or better than mancozeb. Fifty ppm SA, ASA, GABA and SiO2 produced lower disease severity than 100 and 150 ppm, while 150 ppm of BTH, chitosan, BABA and acetic acid produced lower disease severity than 50 and 100 ppm. Two spray applications were enough for season-long protection against blast. BTH gave the highest plant survival and yield. Plants treated with BTH, SA, ASA and chitosan were generally taller, and acetic acid-treated plants flowered earliest. BTH, SA, chitosan, SiO2 and acetic acid consistently produced lower disease ratings and are cheaper than mancozeb. The chemicals showed no antifungal activity against P. grisea in vitro which indicates that the mechanism of control was through SAR induction. The results showed the potentials of these chemicals as elicitors of resistance in rice for rice blast control.
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