The nutritional status and ovarian development of Halyomorpha halys adults collected in an apple orchard and in coppiced trees were investigated in 2000 and 2001, and those of adults reared on apple trees with fruits were investigated in 2002. Adults were observed earlier in the apple orchard than in the coppices; adults immigrated into the apple orchard in May of each year. Female adults had developed ovaries and produced mature eggs. Adults were seldom observed in the orchard after early June, when many adults were observed in the coppices. However, many adults were observed in the apple orchard from mid-July to early August in 2001; the nutritional status of these adults was inferior to that of adults collected in the coppices, and many of the females had undeveloped ovaries. The nutritional status and the number of deposited eggs of the adults reared on apple trees with fruits were significantly inferior to those of adults reared on peanuts and soybeans, foods which were similarly suitable as mature fruit of Japanese flowering cherry. These results suggest that apple fruit is not as good a food for H. halys adults as other plants, but apple is satisfactory when more suitable foods are in short supply.