Abstract: 【Aim】 The aim of the present study is to develop an optical remote sensing technology to automatically monitor insect pests in agricultural fields day and night. 【Methods】 A small reflective telescope was arranged facing a distant dark box, providing a low-lightlevel base line. When insects flied into the telescope field of view, they scattered light from the sun, and the optical information could be collected by the recording system attached to the telescope. At night we instead employed a strong lamp for insect illumination. 【Results】 Insect counting, wing-beat frequency analysis and reflectance spectra recordings were all successfully achieved. This illustrates the possibility to monitor agricultural insect pests with a dark-field back-scattering detection system. Each released known insect species showed a unique reflectance spectrum character. Several insect species, in particular Conogethes punctiferalis (Guenée) and Xenocatantops brachycerus (Willemse) were successfully distinguished from each other by employing the method we introduced. 【Conclusion】 The dark-field back-scattering detection system is practical for monitoring agricultural insect pests in the field through day and night. The wingbeat frequency as well as the spectral contents could be used for pest insect recognition as anticipated.

Key words: Optical remote sensing, dark-field back-scattering detection, insect, Conogethes punctiferalis, Xenocatantops brachycerus