In this study, the effects of phenolic compounds such as tannic acid and gallic acid, and heavy metals such as iron, zinc, copper, nickel and cobalt on the last larval stage of the first generation of H. cunea were investigated. The larvae were collected from mulberry and hazelnut trees in the district of Carsamba, Samsun in 2016. 18 foods in total were prepared; two foods by adding 5% concentration of tannic acid and gallic acid to the artificial diet (dry weight), 5 foods by preparing nickel, zinc, copper, cobalt and iron solutions prepared at 8% concentrations, 10 foods by adding 8% concentrations of heavy metal solutions to 5% concentrations of tannic acid and gallic acid separately, and a control diet. Compared to those fed with control food, the consumption amount of the larvae whose diet contained iron, zinc and copper decreased, whereas it increased in the ones fed with nickel and cobalt containing foods. Pupae weight of the larvae fed with tannic acid and metals added(other than nickel) to it has decreased compared to the larvae in control group. While the amount of pupa protein was the lowest in larvae fed with the food in which both gallic acid and zinc used, it was highest in larvae fed with food containing gallic acid. The pupa lipid amount of the larvae fed with foods supplemented with iron, zinc, copper and cobalt were lower than the control group larvae. The longest development time was observed in the larvae in food groups where iron was added to food alone and tannic acid and iron were added together. The results in this study have shown that the addition of secondary compounds and heavy metals together to the artificial food content may increase toxicity of compounds (synergism) or reduce it (antagonism).