Influence of Farming Systems on Yellow Stem Borer (Scirpophaga incertulas) Suppression and Natural Enemy Dynamics in Summer Rice Ecosystems

Abstract

The yellow stem borer (YSB), Scirpophaga incertulas (Walker), is a monophagous pest and an economically important pest that causes substantial yield loss in paddy. Due to injudicious use of synthetic chemicals for the management of the yellow stem borer leads to harmful effects on human health and natural enemies in the paddy ecosystem. Hence, the present study was conducted to evaluate different farming methods like natural farming (NF), organic farming (OF), conventional farming (CF) and farmers’ practices (FP) against YSB in paddy. The experiment was carried out at the Agricultural and Horticultural Research Station, Honnavile, Shivamogga during the summer cropping seasons of 2021 and 2022. The results revealed that farmers practices (Chlorantraniliprole 0.4% GR @ 12kg/ha) significantly reduced dead heart (6.49 %) and white ear head (3.22 %) incidence in paddy. This was followed by conventional farming (Chlorantraniliprole 0.4% GR @ 10kg/ha), which recorded dead heart (6.89 %) and white ear head (3.85 %). However highest percentage of dead heart and white ear head was observed in natural farming and organic farming treatment. A significantly higher population of natural enemies (coccinellids and spiders) was recorded under natural farming (9.98), followed by organic farming (9.65).The yield was significantly higher in the conventional farming that is 55.76q/ha followed by farmer’s practices 55.18q/ha. The highest cost-benefit ratio was recorded in the natural farming plot followed by the conventional farming plot, compared to other treatments.