Soil application of silicon reduces yellow stem borer,Scirpophaga incertulas(Walker) damage in rice

Abstract

The effect of soil application of rice husk ash (RHA), a cheap renewable source of silicon, and imidazole (a silicon solubilizer and carrier) on yellow stem borer (YSB), Scirpophaga incertulas (Walker), and its damage to rice plants were investigated. Treatments included soil application of RHA (T1), imidazole (T2), RHA + imidazole (applied once at vegetative stage, T3) and RHA + imidazole (applied twice at both vegetative and booting stages of crop growth, T4) with an untreated control (T5). The effect was tested in five varieties, viz., BPT 5204, KRH2, Pusa Basmati 1, MTU1010 and Vandana. All the soil treatments reduced damage by YSB at vegetative and reproductive phases across five varieties as compared to untreated control. Scanning electron micrograph and electron‐dispersive X‐ray spectrum analysis of stem tissue of rice variety BPT 5204 treated with silicon revealed the enhanced deposition of silicon in cell walls and 2.1‐ to 5.3‐fold increase in silicon content across treatments. Larvae collected from the silicon‐treated plants had worn mandibles, and the histological studies showed rupture of the peritrophic membrane, increased vacuolation, disintegration of columnar cells and discharge of cellular contents into the gut lumen due to abrasion of midgut epithelium, as compared to untreated control where the columnar cells and midgut lining were intact. Although all the treatments were effective, T4‐imidazole applied twice along with RHA was more effective in reducing YSB damage followed by T3‐imidazole applied once with RHA at tillering stage, T2‐imidazole alone and T1‐RHA in the descending order of efficacy.

Silicon-mediated and constitutive resistance to Rhopalosiphum maidis (Hemiptera: Aphididae) in corn hybrids

“…Several studies have confirmed the negative effect of silicon on the biology of aphids in grasses, such as sorghum and wheat, with the reduction of aphid fertility and survival and, consequently, a reduction in insect population growth on plants on silicon-amended soil (Carvalho et al ., 1999; Basagli et al ., 2003; Moraes et al ., 2004; Gomes et al ., 2005; Costa et al ., 2007; Dias et al ., 2014). Silicon can confer resistance against insects by forming a physical barrier by its deposition on tissue cell walls (Dayanandam et al ., 1983; Epstein, 1994; Barbosa Filho et al ., 2000), by injuring the midgut of insects (Jeer et al ., 2017), as well as by inducing the production and activation of plant defense compounds (Fawer et al ., 1998; Gomes et al ., 2005; Gomes et al ., 2008; Han et al ., 2016; Yang et al ., 2017).…”

“…However, such positive effects of silicon are not always evident, since its accumulation differs among plant species and among genotypes of the same species (Epstein, 1999; Deren, 2001; Ma & Takahashi, 2002; Hodson et al ., 2005; Mitani & Ma, 2005; Keeping & Reynolds, 2009; Guntzer et al ., 2012). Several studies have found that silicon application can induce insect resistance by enhancing non-preference, reducing rates of plant colonization, or by antibiosis, reducing insect fecundity, or increasing mortality of phytophagous insects (Moraes et al ., 2004, 2005; Gomes et al ., 2005; Costa et al ., 2007; Dias et al ., 2014; Almeida et al ., 2015; Reynolds et al ., 2016; Alvarenga et al ., 2017; Jeer et al ., 2017). Genotypes with a high degree of constitutive resistance absorb greater amounts of silicon, further enhancing their resistance (Reynolds et al ., 2009, 2016).…”

Exploration of silicon functions to integrate with biotic stress tolerance and crop improvement

“…Deposition of phytoliths enhances plant immunity and physical resilience, and serves as a physical barrier to fungal penetration [ 41 , 42 ]. Silicon deposition may also wear away the feeding mouthparts, or mandibles of insects [ 43 ], decrease plant digestibility for both insect and mammalian herbivores [ 21 , 44 , 45 ], and have an adverse effect on herbivores [ 46 ]. Importantly, plant tissue silicification may be induced more in those plants which are highly attacked by various organisms [ 42 , 47 ].…”

Life Table and Preference Choice of Frankliniella occidentalis (Thysanoptera: Thripidae) for Kidney Bean Plants Treated by Exogenous Calcium

“…Numerous studies have shown that the application of exogenous abiotic elicitors can induce plant resistance to insect herbivores [ 9 ]. For instance, exogenously applied silicon improved the resistance of rice plants to yellow stem borer Scirpophaga incertulas (Lepidoptera: Crambidae) and caterpillar Cnaphalocrocis medinalis (Lepidoptera: Pyralidae) by increasing larval mortality and reducing larval mass, respectively [ 12 , 13 ]. Both longer development time and lower numbers of aphids Diuraphis noxia (Homoptera: Aphididae) were observed on wheat plants treated with exogenous potassium, in comparison with untreated plants [ 14 ].…”