Induction of resistance by enhancing silicified cells against shoot fly and stem borer pests of barnyard (Echinochloa frumentacea) and finger millet (Eleusine coracana)

Field experiments were conducted at Annapannai, Kudumiyanmalai and Agricultural College and Research Institute, Madurai in barnyard and finger millets to explore the efficacy of organic and inorganic sources of silica against borer pests. The per cent dead heart damage due to shoot fly in barnyard millet ranged from 4.16 to 7.67 among the treatments, the lowest was recorded in the treatment with basal application of 75% of 60 kg of calcium silicate/ha along with Trichogramma chilonis 5 cc/ha. But the incidence of dead heart due to stem borer was significantly less in the treatment with basal application of 75% of 60 kg of silica/ha along with neem formulation 2 mL/L and release of Trichogramma chilonis (5.53%) which was on par with 50% of 60 kg of silica/ha along with application of neem formulation 2 mL/L and release of T. chilonis (5.57%) and basal application of 60 kg of silica as calcium silicate alone (5.72%). Similarly, the white ear incidence ranged from 4.97 to 13.86% among treatments. The lowest incidence was recorded in the treatment with basal application of either 75% of 60 kg of silica as calcium silicate/ha along with need-based application of neem formulation 2 mL/L and release of T. chilonis. The number of silicified cells (7.11 Nos./sq.cm) and phenol content (4.16 mg/g) were significant in the treatment using 60 kg of silicon as calcium silicate which was on par with 75% of 60 kg of silicon as calcium silicate with neem formulation 2 mL/L. Regarding yield of barnyard millet, yield varied from 0.65 to 1.82 t/ha, the maximum in the treatment with basal application of 75% of 60 kg of silica/ha along with application of neem formulation 2 mL/L and release of Trichogramma chilonis (1.82 t/ha) with BC ratio of 2.20. In finger millet also, the same trend was observed. Observation on dead heart damage due to stem borer was recorded on 40 DAT. The per cent damage ranged from 4.14 to 10.23 among the treatments. The lowest incidence of dead heart was recorded in the treatment with basal application of 60 kg of calcium silicate/ha (4.14%) which was on par with basal application of 75% of 60 kg of silica/ha along with application of neem formulation 2 mL/L and release of Trichogramma chilonis (4.57%) and 50% of 60 kg of silica/ha along with application of neem formulation 2 mL/L and release of T. chilonis (4.61%). Similarly, the white ear incidence ranged from 5.21 to 17.20% among treatments. The lowest incidence was recorded in the treatment with basal application of either 75% of 60 kg of silica as calcium silicate/ha along with need-based application of neem formulation 2 mL/L and release of T. chilonis. The number of silicified cells (5.07 nos./sq.cm) and phenol content (3.20 mg/g) were significant in the treatment using 60 kg of silicon as calcium silicate. In finger millet, yield was maximum in the treatment with basal application of 75% of 60 kg of silica/ha along with application of neem formulation 2 mL/L and release of T. chilonis (2.56 t/ha) with BC ratio of 2.10.