Rice husk ash and imidazole application enhances silicon availability to rice plants and reduces yellow stem borer damage

• Published in: Field crops research 2018-07, Vol.224, p.60-66
• Main Authors: Jeer, M., Suman, K., Maheswari, T. Uma, Voleti, S.R., Padmakumari, A.P.
• Format: Article
• Language: English
• Subjects: Imidazole; Larval mandibles; Rice; Rice husk ash; Silicon; Yellow stem borer
• ISSN: 0378-4290; 1872-6852
• DOI: 10.1016/j.fcr.2018.05.002

[Display omitted] •Soil application of Rice husk ash and/or imidazole-a solubiliser cum carrier of silicon enhanced the silicon content in the rice stems.•Mandibular wearing of yellow stem borer larvae fed on Si treated stems was evident as the incisor length was reduced.•The dead heart and white ear damage by yellow stem borer larvae is significantly low in the Si treatments.•The cost of crop protection is low with higher yield in Si treatments as compared to untreated control.•The benefits of application of rice husk ash + imidazole (twice) is at par with that of a single granular application of an insecticide. Silicon (Si) has been implicated to reduce damage by rice pests. In this study we validate the field efficacy of rice husk ash (RHA) and imidazole, alone and in combination, against damage by yellow stem borer (YSB) under field conditions for two seasons in five rice cultivars. Field application of RHA and imidazole, either alone or in combination, enhanced Si deposition (43–59.8 mg g−1) in stem tissues of rice plants as compared to untreated control (30.2 mg g−1). Deposited Si caused significant wearing of mandible incisors, and lowered larval density, thereby decreasing YSB damage and increasing the grain yield significantly. RHA and imidazole did not alter the total sugars and total phenol content in rice cultivars. Field application of imidazole along with RHA at vegetative phase and again at booting stage was on par with insecticidal treatment (carbofuran 3G) with respect to per cent damage, larval density and grain yield. The B: C ratio in the Si treatments varied from 1.16 to 1.31 and T4-RHA + imidazole (applied twice) was at par with one granular insecticide application (1.32) but higher than the untreated control (1.0). RHA and imidazole can be integrated as one of the eco-friendly components in the present scenario of climate change for the management of YSB in rice.