Ethephon (ETF), one of the plant growth regulators, is used in agricultural systems as a valuable tool due to its property of regulating fruit maturation. Here, we aimed to investigate the toxic effects of ETF on the hemolymph metabolites of the greater wax moth, G. mellonella which is an experimental animal and a serious pest in wax. Different doses of ETF (250-390 μg/5 μl) were injected with force feeding method to the last instars and the effects of ETF on the level of hemolymph protein, lipid, and glucose were estimated spectrophotometrically at 24 and 48 h after treatments. The levels of protein, glucose, and lipid in hemolymph showed dose- and time-dependent changes. These results indicated that treatment with ETF may result in significant physiological changes in pests. Consequently, it is likely that ETF can be a promising agent for use in integrated pest management programs as ecofriendly biopesticides.