Trap crop selection and economic threshold based ecological management of Spilosoma obliqua Walker (Lepidoptera, Arctiidae) for sesame

Abstract

The stage-specific life table and nutritional ecology of a Spilarctia obliqua (Walker) along with respective economic thresholds (ETs) on four different crops such as sesame (Sesamum indicum), castor (Ricinus communis), jute (Corchorus capsularis) and sunflower (Helianthus annuus) were studied during 2020-2022. The feeding and population dynamics of S. obliqua were significantly affected by the hosts in terms of host suitability or susceptibility (sunflower>jute>castor>sesame). The ET of S. obliqua on sesame (40.59±2.12 pests m-2 area) was significantly (F3,8=4.72, P=0.031) higher than the other crops (sunflower<jute<castor). Subsequently, the three most suitable hosts (sunflower> jute>castor) were tested in a multi trap cropping system for sesame as main crop in a specific pattern depending on respective susceptibility. Data from the model trap cropping (without pesticide) supported minimum infestation of S. obliqua and other pests along with more predators on sesame with higher benefit cost ratio (BCR) and more (11.82%) carbon sequestration (CS) in same area relative to monoculture (with pesticide) of sesame. It supports pesticide free high production and better CS than sole culture of sesame for climate smart agriculture.