Disease-Reducing Effect of Chromolaena odorata Extract on Sheath Blight and Other Rice Diseases

Abstract

Sheath blight caused by Rhizoctonia solani (teleomorph: Thanatephorus cucumeris) is a major cause of crop loss in intensive rice production systems. No economically viable control methods have been developed. We screened aqueous extracts of common herbal plants that could reduce sheath blight lesions and found that foliar spraying and seed soaking application of extracts of either fresh or dried leaves of Chromolaena odorata gave up to 68% reduction in sheath blight lesion lengths under controlled and semi-field conditions. The observed reductions were not dependent on growth conditions of C. odorata and rice cultivar. The effect was observed until 21 days after inoculation and was not dependent on microbial activity. Under semi-field conditions, extracts also reduced severity of other important rice diseases, i.e., blast (Pyricularia oryzae) using foliar spray (up to 45%), brown spot (Bipolaris oryzae) using seed treatment (up to 57%), and bacterial blight (Xanthomonas oryzae pv. oryzae) using both application methods (up to 50%).

Effect of aqueous extracts of some indigenous medicinal plants on sheath blight of rice

“…The finding are consistent with data obtained from previous studies (Kummee and Intaraksa, 2008;Plodpai et al, 2013). Khoa et al (2011) reported the diseasereducing effect of Chromolaena odorata extract on sheath blight and other rice diseases. Nguefack et al (2013) found that plant extracts and an essential oil are effective for controlling rice disease, tillering, number of panicles and yield increase.…”

“…Clove extract completely inhibited the growth of R. solani, R. oryzae, R. oryzae-sativae and Sclerotium hydrophilum (San-Aye and Matsumoto, 2011). Siam weed extract was found to be effective in reducing severity of blast, brown spot and bacterial leaf blight disease of rice (Khoa et al, 2011). Plant extracts contain metabolites including alkaloids, glucosinolates, indole, phenolics, phenylpropanoids, saponins, stilbenes and terpenoids have been reported to exhibit antifungal properties (Dixon, 2001;Lanzotti et al, 2012).…”

Efficacy of Aqueous Leaf Extract of Medicinal Plants against Blast and Brown Spot Disease of Rice

“…tabacum, A. vera, A. indica, were found significant to manage rice blast disease in-vitro and in-vivo. The research is also in accordance with Khoa et al, (2011) who observed that foliar spray of aqueous extracts of herbal plants have been found effective in reducing rice blast severity. Results on suppression of Bipolaris oryzae under various concentration of plant extracts were significant.…”

Activity-guided separation of Chromolaena odorata leaf extract reveals fractions with rice disease-reducing properties

“…Fractionation of Chromolaena odorata extract Cultivation of C. odorata and harvest of leaves took place as described by Khoa et al (2011). The initial extraction of the bioactive compounds was carried out in methanol and water.…”

“…Tests of aqueous extracts of wild plants from Vietnam for their ability to control sheath blight revealed that an extract from Chromolaena odorata (Siam weed) reduced disease severity significantly (Khoa 2010;Khoa et al 2011). The C. odorata extract could also control other important pathogens of rice like Bipolaris oryzae, Pyricularia oryzae and Xanthomonas oryzae pv oryzae.…”