Surround Wettable Powder Crop Protectant (kaolin particle film) contains processed white kaolinite (90% pure kaolinite), a 1:1 aluminosilicate clay, having a brightness quality greater than 85%. Producers apply it to crop canopies to suppress and/or control various stresses affecting agricultural crops. In south Texas, little information is available on the effects that kaolin applications have on the spectral reflectance properties of crop canopies. The objective of this study was to evaluate the field spectra of cotton (Gossypium hirsutum L.) and pepper (Capsicum annum L.) canopies treated with kaolin particle film. Treated and nontreated plants growing in experimental plots near Weslaco, Texas (26.1281N, 97.9625W) were assessed. Data were obtained with a visible to near-infrared light sensitive hyperspectral radiometer on 1 June 2004 and 9 December 2004 for the cotton and pepper plants, respectively. The two-sample t test and the reflectance sensitivity were employed to evaluate the data. The visible region (ranging from 400-700 nm) of the light spectrum consistently separated treated from nontreated plants, with treated plants having significantly higher (P < 0.05) visible reflectance values than nontreated plants. Sensitivity analysis showed that the blue region of the visible spectrum (ranging from 400-500 nm) was most responsive to kaolin-treated plant canopies. These results indicate that kaolin applications to crop canopies affect their spectral response, supporting further testing of remote sensing systems as tools to assist south Texas growers in determining when to re-apply it to crop canopies.