Effect of salicylic acid, nano-chelated iron, and vermiwash on the resistance of four canola cultivars against Plutella xylostella (L.) (Lepidoptera: Plutellidae)

The diamondback moth, Plutella xylostella, is a highly polyphagous global pest that seriously damages not only canola but also a wide range of plants within the Brassicaceae family. This study aimed to evaluate and compare the individual efficacy of salicylic acid (SA), nano-chelated iron (Fe-NPs), and vermiwash in enhancing resistance in four canola cultivars against canola, P. xylostella. We hypothesized that the application of these elicitors would negatively impact the pest’s life history and population growth parameters, with effects varying significantly across cultivars. The study was conducted under laboratory conditions. The age-stage, two-sex life table theory was employed to analyze the pest’s development, survival, reproduction, and population parameters. Our results revealed that the interaction between cultivar and fertilizer significantly impacted the life table of P. xylostella. The larval and developmental periods were longer in vermiwash-treated cultivar RGS003 than in water-treated Zarfam. The highest male longevity was found in SA-treated cultivar Julius and water-treated RGS003. The fecundity of P. xylostella was higher in water-treated Julius than vermiwash-treated RGS003. The intrinsic reproduction rate (r) and finite reproduction rate (λ) of P. xylostella increased and decreased significantly in water-treated Julius and vermiwash-treated RGS003. In conclusion, integrating Brassica cultivars with vermiwash fertilizer a promising alternative to synthetic insecticides. Furthermore, the RGS003 cultivar, when combined with vermiwash, significantly affected P. xylostella compatibility compared to the other cultivars and elicitors.