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

Fig. 4. Effect of increasing concentrations of CT-100 on the symptom development 8 days post inoculation. Seven leaves (49 leaflets/treatment) were harvested from greenhouse-grown Russet Burbank plants and inoculated with P. infestans (25 µl of a 20,000-sporangia-per-ml suspension per leaflet) 4 days after the following treatments were applied in a volume of 25 ml per plant (two plants/treatment): water alone, chitosan (50 µg/ml), copper hydroxide (600µg/ml), copper hydroxide (600 µg/ml) plus chitosan (50 µg/ml), chlorothalonil (3.2 mg/ml), chlorothalonil (3.2 mg/ml) plus chitosan (50 µg/ml), chitosan (50 µg/ml) plus CT-100 2X (28 µg/ml), chitosan (50 µg/ml) plus CT-100 4X (56 µg/ml), chitosan (50 µg/ml) plus CT-100 8X (112 µg/ml), CT-100 2X (28 µg/ml), CT-100 4X (56 µg/ml), or CT-100 8X (112 µg/ml ). Leaves receiving no treatment also were inoculated. Values of percent symptomatic leaflet area with the same letter are not significantly different, based on an LSD value of 10.27. (The severity of symptoms following the CT-100, 8-fold treatments was primarily related to copper toxicity in addition to the infection-related symptoms.)



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