Riptortus pedestris (Fabricius) (Hemiptera: Alydidae) recently become an important fruit-spotting bug of apple and sweet persimmon trees in Korea. Although fruits of cultivated species are generally known to be unsuitable food for the fruit-spotting bugs, dietary importance of fruits of apple and sweet persimmon for R. pedestris is unknown. We evaluated fruits of apple and sweet persimmon with or without soybean seeds as a food source for R. pedestris by investigating nymphal development time, nymphal mortality, preovipositional period, fecundity, and adult size in the laboratory. None of 1st instar R. pedestris fed only on a fruit of apple or sweet persimmon became second instar nymph. When provided with soybean seeds together, both the fruits did support the nymphal development and the reproduction of R. pedestris. However, diets including soybean and one of the fruits were not better than control diets consisting of soybean seeds with or without vitamin C. Therefore, apple and sweet persimmon are not essential food sources for the development and the reproduction of R. pedestris. These results suggest that R. pedestris may not reproduce on the fruit trees, thus explain absence of either their eggs or their nymphs on the fruit trees in the fields.