Estimation of thrips (Fulmekiola serrataKobus) density in sugarcane using leaf-level hyperspectral data

The aim of this study was to investigate the potential use of leaf-level hyperspectral data to predict the density of sugarcane thrips Fulmekiola serrata (Kobus). A hand-held spectroradiometer was used to make the spectral measurements on spindle leaves of 4- to 5-month-old plants of sugarcane cv. N19 growing in commercial fields near Umfolozi, South Africa. A random forest algorithm followed by partial least squares regression was used for the analysis. Developed models were adequate to predict nymph numbers in December and adult numbers in March, but different models were needed for the thrips life stage assessed and the season when the estimation took place.