In this study, synergistic effects of secondary compounds on the total diet amount of consumption, pupae weights, lipid and protein amounts of pupae, and growth periods at the final larva stage of Malacosoma neustria, which is a polyphagous species, were investigated. 9 diets were prepared by adding tannic acid, gallic acid and p-Coumaric acid at different concentrations (1, 3, 5%) in the control diet. 3 diets with double combination were prepared by adding tannic acid, gallic acid and p- Coumaric acid at 3% concentration in control diet. 1 diet with triple combination was prepared and total of 14 diet with non-preferred nutrition experiments were conducted. Chloroform was used in determining the amount of lipid. Protein analysis was performed with a semi-micro Kjeldahl method using a Kjeltec Auto 1030 analyser (Tecator, Sweden). ANOVA-Dunnet test was used in statistical analyses. In comparison with the control group, the total consumption of M. neustria larvae and the amounts of pupa protein and lipid were found to decrease as the concentration of substance added to diets containing both tannic acid and p-Coumaric acid increased. In gallic acid supplemented diets, it was determined that when the gallic acid concentration increased, the total consumption amount also increased. As the concentration of tannic acid added to the diets increased, the development time was found to be prolonged. It has been observed that the larvae had resistance against the related concentrations and combinations of secondary compounds used in this study and they could reach the pupae stage.