Population ecology and economic thresholds-based time series for climate smart pest management of Spilosoma obliqua Walker (Lepidoptera: Arctiidae) on three sesame cultivars

Abstract

BackgroundSesame (Sesamum indicum L.) is a widely used oil seed crop throughout the world but its productivity is extremely low due to use of low yielding cultivars as well as biotic stress for the major pest Spilosoma obliqua Walker. But even today, farmers generally use broad-spectrum synthetic pesticides for their management injudiciously without considering any economic threshold (ET) limit and creates ecosystem crisis. So, time-based ecologically sustainable management of the said pest and selection of a superior cultivar of sesame was studied by stage-specific two-sex pooled life table and nutritional ecology of S. obliqua on three sesame cultivars (Rama, Shubhra and Amrit) along with their economic thresholds (ETs) in 2019.ResultsThe nutritional ecology and population dynamics of S. obliqua were significantly affected by the host phytoconstituents in terms of host suitability or susceptibility (Rama > Shubhra > Amrit). The mean EIL and ETL for S obliqua was 36.316 ± 3.911 and 33.243 ± 2.734 pests/m2, respectively on cv. Rama that were significantly (F2,6 = 5.421–5.435; P ≤ 0.042) lower than Shubhra and Amrit. For a single pest per m2 (30 ± 2 plants/m2) the possible time that can be taken to reach EIL (Ti) and ETL (Tt) were 39.132 ± 3.969 and 38.132 ± 3.969 days, respectively on cv. Rama which were also significantly (F2,6 = 26.551; P = 0.001) lower than the other cultivars. The seed yield and benefit cost ratio (BCR) were 857.099 ± 0.000 (Kg/ha) and 0.607 ± 0.000, respectively for cv. Rama that were significantly (P < 0.05) lower than the others.ConclusionsIt will enable growers to find the most preferred cultivar (Rama > Shubhra > Amrit) based on BCR values irrespective of their biotic resistance (Rama < Shubhra < Amrit) due to host antibiosis. Even, the ETs-based time series for judicious management of the pest along with carbon sequestration efficiency (CSE) will also support superiority of the cultivars (Rama > Shubhra > Amrit) towards climate smart pest management (CSPM) of sesame and or other such crops in near future.