~ 1662 ~ Journal of Pharmacognosy and Phytochemistry 2020; 9(3): 1662-1665 E-ISSN: 2278-4136 P-ISSN: 2349-8234 www.phytojournal.com JPP 2020; 9(3): 1662-1665 Received: 01-03-2020 Accepted: 04-04-2020 Pedda Ghouse Peera SK M.S. Swaminatham School of Agriculture, Centurion University of Technology and Management, Paralakhemundi, Odisha, India Rubina Khanam ICAR-National Rice Research Institute, Cuttack, Odisha, India Corresponding Author: Pedda Ghouse Peera SK M.S. Swaminatham School of Agriculture, Centurion University of Technology and Management, Paralakhemundi, Odisha, India Fly ash as a source of silicon and potassium for mitigating Ear head bug ( Leptocorisa acuta ) in rice under different abiotic stress condition Pedda Ghouse Peera SK and Rubina Khanam Abstract Experiments were carried out in two field conditions (induced drought and flood stress) to analyse the effect of fly ash on ear head bug population. The population of ear head bug was assessed at regular intervals on plants imposed with treatments including fly ash, Silicate Solubilizing Bacteria (SSB), Farm yard manure (FYM), and graded levels of soil test based potassium. The results revealed that the combination of Fly ash, SSB, FYM, with graded level of soil test based potassium significantly reduced the incidence of ear head bug as compared to untreated plots. The silicon content was analysed in ear head at flowering stage and it was negatively correlated with the insect population. As the age of the plant increased, silicon content proportionately increased in the plants at different growth stages. The Si present in the fly ash gets deposited in plant which in turn inhibits the feeding activity of ear head bug. Application of fly ash as a source of silica and potassium with SSB, FYM with STBK reduced the ear head bug population and increased the yield in rice. Keywords: Fly ash, silica, ear head bug incidence Introduction Insect pests are one of the major biological constraints that limit crop production throughout the world (Ukwungwu, 1990) [13] . Among all insect control methods, the planting of pest resistant varieties is one of the most effective (Ukwungwu, 1990) [13] because it leaves no insecticide residues in food or the environment, and is constantly effective. However, pest damage may also be reduced through careful management of the nutrient requirements of the crop or amendments with mineral nutrients, such as silicon (Si), that reduce crop susceptibility to pests (Meyer and Keeping, 2005) [8] . This is because the development of phytophagous insects often depends on the physiological condition of host plants, and particularly their nutrient and stress status (Sétamou et al., 1993) [11] . For many years, Si deficiency in crops went unrecognized, and this element was widely regarded as non-essential for plant growth, although often present in the highest concentration amongst inorganic constituents (Jones and Handreck, 1967) [5] . However, there is now a greater consensus amongst scientists in the role of Si as a “functional” plant nutrient (Bhavnagary et al., 1988; Epstein, 1999) [1, 4] . Silica content in the plant is reported to play an important role in strengthening the cell walls of the plants (Painter, 1951) [9] and enhances resistance to both pests and diseases in the field (Qin and Tian, 2004) [10] and in storage (Korunic, 1997) [6] . Fly ash is a major industrial waste in India. It is a by-product of thermal power station where electricity is produced by burning finely powdered coal. Fly ash considered to be a rich source of Si and application of fly ash in Si deficient soils has been demonstrated to improve the Si content of rice and growth (Lee et al., 2006) [7] . Chandramani et al. (2009) [2] reported that the combination of FYM, biofertilizers, lignite fly ash and neem cake applied in splits reduced insect pests and increased the content of Si and potassium in plants which induced resistance to pests in plants. Sujatha et al. (1987) [12] suggested that phenol, silica, phosphorous, potassium, calcium, sulphur and iron contents were positively correlated with resistance, while the protein, nitrogen, zinc and manganese contents were negatively correlated with resistance. Hence silicon content in rice plant was found to be negatively correlated with the incidence of ear head bug in rice. Materials and Methods Two field experiments were conducted under induced drought and flood condition in split plot design with three replications. The plot size was 5x4 m 2 with 4 main plot treatments and 5 sub plot treatments.