Short Communication Preliminary Study on Sugarcane Thrips (fulmekiola Serrata) Damage Detection Using Imaging Spectroscopy

In 2004, sugarcane thrips Fulmekiola serrata (Kobus) (Thysanoptera: Thripidae) was for the first time detected in southern African sugarcane. Since then it has become widespread in South Africa, and any control strategy would benefit from identifying and monitoring damage caused by this pest. Imaging spectroscopy is being investigated for this purpose, and is used in conjunction with space-borne remote sensing at regional and farm level. Hand-held devices are used at field or sub-field level. In this study, a hand-held field spectroradiometer was used at leaf level in the 350-2500 nm range of the electromagnetic spectrum. Reflectance spectra of thrips-damaged sugarcane leaves from varieties N19 and N12 were investigated. Significant differences in spectral reflectance were detected in leaves with increasing levels of thrips damage. Wavebands in the red edge region of the visible portion of the electromagnetic spectrum gave the highest significant differences. It is hypothesised that this could possibly be associated with thrips-induced chlorophyll and nitrogen deficiencies.