SOME WILLOW STEM BORERS AND THEIR CONTROL MEASURES

The willow is one of the principal kinds of trees planted in the shelterbelts along the Hart River, a tributary of the Yangtze River in Hupeh Province. However, it is not easy to have the willows grown vigorously into an exuberant shelterbelt, for there are many insect pests harming the trees: some of them eat leaves, others suck sap, and still others bore holes on the stems. The stem-boring insects are the worst of all. They bore and eat into the branches and stems, causing frequently fatal damages on willows over vast stretches of land. This has given rise to the popular saying: "Out of ten willows nine are hollow." In the present paper attempts have been made to study the rules governing the life cycle of some important stem borers, the characteristics of their damage, their natural enemies, and the indigenous measures of their prevention and control.