Effect of different sunflower cultivars on nutritional and physiological responses of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae).

Helicoverpa armigera (Hübner) is one of the invasive pests of crops worldwide, and several studies have focused to compare the growth, consumption, and digestion of H. armigera larvae on different plants. However, studies evaluating the insect's food consumption and digestive physiological response using biochemical profile of sunflower cultivars are scarce. In this research, the impacts of various sunflower cultivars (Golsa, Ghasem, Shams, and Zarrin) based on artificial diet were evaluated on enzymes activity and nutritional responses of H. armigera. Among the different sunflower cultivars, the relative growth rate (RGR), efficiency of conversion of ingested food (ECI), and efficiency of conversion of digested food (ECD) were highest on Ghasem. Likewise, the heaviest weight of larvae and pupae was obtained on Ghasem, while the lightest was found on Zarrin. The highest proteolytic activity was detected on Zarrin, whereas the highest amylolytic activities were found on Ghasem and Shams. In addition, ECD and RGR values of H. armigera larvae were negatively correlated with secondary metabolites content (phenol). The cluster analysis revealed that Ghasem was a nutritionally appropriate cultivar for H. armigera, while Zarrin illustrated the greatest level of tolerance against this polyphagous pest. These results could be useful in selection of sunflower cultivars for cultivation and breeding programs that entail H. armigera control. [ABSTRACT FROM AUTHOR]