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

Fig. 5. Effect of processed copper sulfate pentahydrate (CT-100) and reagent grade copper sulfate pentahydrate (Cu) on late blight development. Duplicate sets of potato plants were untreated or sprayed (25 ml per plant) with: water, chitosan (25 µg/ml); Cu (14 µg/ml), Cu (14 µg/ml) plus Chit (chitosan) (25 µg/ml), CT-100 (14 µg/ml), CT-100 (14 µg/ml) plus Chit (25 µg/ml), Cu 10X (140 µg/ml), and Cu 10X (140 µg/ml) plus Chit (25 µg/ml). Four days following application of products, 49 leaflets from each treatment were inoculated with P. infestans, US 8 (25 µl of a 20,000-sporangia-per-ml suspension) and observed for 10 days post inoculation. Yellowing of leaflets was observed for the Cu, Cu/chitosan, CT-100, Cu10X, and Cu10X/chit treatments. Values of percent symptomatic leaflet area with the same letter are not significantly different based on LSD0.05 = 8.73.



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