Feeding deterrence towards Helicoverpa armigera by Tithonia diversifolia tagitinin C-enriched extract

The use of botanical insecticides is a tactic that can be highly useful for the management of Helicoverpa armigera populations in the field. However, most botanical insecticides are produced using primarily macerated leaves. The problem with this process is that all components of the leaves are present in the extract, and not just the plant defence chemicals. Therefore, the objective of this research was to evaluate the feeding deterrence of a tagitinin C-rich leaf rinse extract (TagCE) obtained from Tithonia diversifolia (which concentrates mainly the plant defence substances) towards H. armigera larvae. The RP-HPLC-PDA analytical method allowed the identification and quantification of the major constituent TagCE, showing that this compound is suitable to be considered as its chemical marker. Regarding biological activity, we observed high insect mortality, with up to 80%, and high antifeedant activity for H. armigera larvae for all host plant species treated with T. diversifolia extract. These results open up the possibility to use T. diversifolia extract as a potential botanical insecticide, mainly against plant-defoliating Lepidoptera.