仿爱夜蛾成虫排泄物对敦煌石窟壁画的损害及其治理

通过模拟实验与现场调查相结合的方法研究了仿爱夜蛾Apopestes spectrum (Esper)成虫对敦煌石窟壁画的损害及其治理。结果表明：仿爱夜蛾成虫在石窟中的时空分布具有一定的规律性，成虫密度在上、中、下3层洞窟呈依次增加的趋势，与洞窟内温、湿度有关；在1年内表现为8月份洞窟内成虫数量多，与洞外成虫羽化的高峰期相一致。成虫排泄物污染壁画面积年平均达150 mm²/蛾，且对不同颜料的影响有差异，对白色和蓝色影响较大，对红色和褐色的影响较小。排泄物不仅直接污染壁画表面，而且，其残余物中含有磷酸盐和碳酸盐等，酸性物质在与壁画颜料、地仗及空气的作用过程中均对壁画产生腐蚀。在开展物理防治的基础上，选用15%灭幼脲三号胶悬剂或2.5%敌杀死乳油，于6月上旬防治2～3龄幼虫，灭幼脲喷药后第10天和敌杀死喷药后72 h的防治效果可分别达到85.6%和97.6%。

Damages by excretion of Apopestes spectrum (Esper) imagos on the Dunhuang murals and their control

Damages by excretion of Apopestes 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.