Low-Level Copper Plus Chitosan Applications Provide Protection Against Late Blight of Potato

Fig. 2. A comparison of CT-100 (processed form of copper sulfate pentahydrate) with and without chitosan 25 µg/ml (Chit) as a sticker on potato late blight. Triplicate plants were sprayed (25 ml/plant) with CT-100 (14 µg/ml), chitosan (25 µg/ml), or CT-100 (14 µg/ml) plus chitosan (25 µg/ml). Each leaflet of the excised leaves was inoculated with 25 µl of a 20,000-sporangia-per-ml suspension of P. infestans and incubated 12 days at 16°C. Values for percent of leaf surface area infected are plotted. Yellowing of leaflets was observed only with the CT-100-only treatment. Values of percent symptomatic leaflet area with the same letter are not significantly different, based on an LSD 0.05 = 9.60.



Image from Plant Health Progress article:
Low-Level Copper Plus Chitosan Applications Provide Protection Against Late Blight of Potato