The population density of Eriophyes chibaensis on young leaves of Japanese pear cv. Nijisseiki increased in mid- to late May, peaked in mid-June to early July, and then decreased in late July. More mites are always found on the underside of leaves than the upperside. The control threshold density for E. chibaensis on Japanese pear cv. Nijisseiki is estimated at 50 to 100 mites per young shoot leaf tip.
