Abstract: Damages by excretion ofApopestes spectrum (Esper) imagos on the Dunhuang murals and their control measures were studied through field investigations and simulating experiments in Mogao Grottoes, Dunhuang and Yulin Grottoes, Yulin, Gansu Province. The results showed that the spatial distribution of A. spectrum imagos within the caves had the following patterns: imago numbers increased from the lower caves to upper caves, and this in turn was closely related with temperature and humidity in caves. The occurrence peak of A. spectrum imagos inside caves was in August, which was consistent with the emergence peak of the moth in fields. Excretion of a single imago could pollute as much as 150 mm2 murals annually in average, but the damages on murals were different due to color variations. Excretion of the moth caused high damages on murals with blue and white colors, slight damages on that with red and brown colors, and low damages on that with red and brown colors. The excretion not only polluted mural surfaces, but also eroded the murals as acidic materials such as phosphates and carbonates within the excrements reacted with color materials, plaster layers and air. Besides the physical prevention method (screening caves against moths), biological agents and chemicals were tested for controlling A. spectrum larvae in the first 10 days of June, and the control efficacies on 2nd-3rd instar larvae of the moth reached as high as 85.6% in 10 days after spraying 15% chloromethiuron and 97.6 % in 72 hours after spraying 2.5% deltamethrin.

Key words: Apopestes spectrum, excretion, mural, damage, control, Dunhuang caves