Relationship of Aerial Broad Band Reflectance to Meloidogyne incognita Density in Cotton

摘要: Aerial images were obtained on 22 July 1999 and 4 August 2000 from five cotton sites infested with Meloidogyne incognita. Images contained three broad bands representing the green (500-600 nm), red (600-700 near-infrared (700-900 nm) spectrum. Soil samples collected assayed for nematodes in fall at these sites. Sampling locations identified images, by locating coordinates of a wide range light intensity (measured as digital number) each single band, combinations bands. There was no band or combination which reflectance consistently predicted M. incognita density. In all 10 site-year combinations, minimum number necessary to estimate density within 25% population mean greater when sampling reflectance-based classes (3 per site) than based entire site one unit. Two sampled multiple times during growing season. At sites, there time season optimal take nematode sampling. infrared photography conducted could not be used accurately determine densities