Exogenous Application of Different Silicon Sources and Potassium Reduces Pink Stem Borer Damage and Improves Photosynthesis, Yield and Related Parameters in Wheat

Abstract

Silicon (Si) and potassium are known to impart tolerance against numerous biotic stresses in crop plants. A study was conducted to determine the effect of diatomaceous earth (DE), a soil-applied Si source and soluble silicic acid, a foliar applied Si source at two levels of potassium for their efficacy against pink stem borer (PSB) incidence and damage in wheat under field conditions for two seasons. The effect of these Si sources and potassium levels on photosynthesis, yield, and related parameters were also studied. Soil application of DE @ 300 kg ha−1 significantly decreased the PSB incidence with the lowest percent white ear damage and recorded the highest grain yield of 3.31 t ha−1. Both soil and foliar applied Si sources along with potassium @ 36 kg ha−1 significantly enhanced the net photosynthesis rate, stomatal conductance, water use efficiency, intercellular CO2 concentration, spike length, spike weight, number of grains per spike, 1000 grains weight and significantly decreased the transpiration rate in contrast to untreated control (no Si application) and insecticidal check. Soil applied Si sources significantly enhanced plant-available Si content in soil solution and thereby Si content in stem tissues of wheat plants in contrast to foliar-applied Si sources. Maximum Benefit: Cost ratio (2.03) was recorded with soil application of DE @ 150 kg ha−1 which was more than recommended insecticidal check (1.74). Both Si sources proved significantly superior to insecticidal check in managing PSB in wheat under field conditions and improved photosynthesis, yield and related parameters, which can be integrated with other practices for sustainable, eco-friendly management of PSB in wheat.