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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #321295
Title: Efficacy of Prophyt and Captan when combined for control of peach scab in Georgia, 2014 (Flameprince)

Author
item BRANNEN, PHILLIP - University Of Georgia
item Bock, Clive
item Hotchkiss, Michael - Mike

Submitted to: Plant Disease Management Reports
Publication Type: Other
Publication Acceptance Date: 6/1/2015
Publication Date: 8/1/2015
Citation: Brannen, P.M., Bock, C.H., Hotchkiss, M.W. 2015. Efficacy of Prophyt and Captan when combined for control of peach scab in Georgia, 2014 (Flameprince). Plant Disease Management Reports. 9:STF007.

Interpretive Summary: Fungicides were evaluated for control of scab in an experimental peach block (‘Flameprince’) in Byron, GA. Chemical formulations were applied at petal fall and shuck split with two subsequent cover sprays. Treatment regimens included: Captan 4L (three treatments were applied at different rates), Prophyt (two treatments were applied at different rates), and Captan 4L + Prophyt (six treatments were applied at different rates in different combinations). At full maturity, 40 fruit were harvested from each plot and assessed for scab. Scab incidence (percent fruit diseased) and severity (lesions per fruit) were recorded. Scab infections and subsequent symptoms can develop throughout the season, but a critical peak in spore production occurs during the period between petal fall and shuck split. Early-season (petal fall and shuck split) sprays require fungicides with greater efficacy than the standard sulfur cover sprays which are utilized for the remainder of the season. There was no significant difference between treatments or from the non-treated control for scab incidence. Aside from the three low rate treatments: (Captan 4L 1 qt/A, Prophyt 1 pt/A, and Captan 4L 1 qt/A + Prophyt 1 pt/A), all treatments were effective in reducing scab severity compared with the non-treated control. The addition of Prophyt to Captan did not reduce disease levels over those observed with Captan alone or vice versa.

Technical Abstract: Fungicides were evaluated for control of scab in an experimental peach block (‘Flameprince’) located at the USDA Research Station in Byron, GA. Chemical formulations were applied with an airblast sprayer (100 gal/A spray volume) on 27 March (petal fall to 1% shuck split), 3 Apr (shuck split to 10% shuck off) and two subsequent cover sprays on 21 April and 5 May. Treatment regimens included: Captan 4L (three treatments were applied at different rates), Prophyt (two treatments were applied at different rates), and Captan 4L + Prophyt (six treatments were applied at different rates in different combinations). Four replications of each treatment were assigned to a randomized complete block design, with each plot consisting of three trees. All cultural practices were in keeping with production methods commonly observed throughout the Southeast. At full maturity, 40 fruit were harvested from each plot and assessed for scab (8 Jul). Scab incidence (percent fruit diseased) and severity (lesions per fruit) were recorded. Scab infections and subsequent symptoms can develop throughout the season, but a critical peak in spore production occurs during the period between petal fall and shuck split. Early-season (petal fall and shuck split) sprays require fungicides with greater efficacy than the standard sulfur cover sprays which are utilized for the remainder of the season. There was no statistically significant difference between treatments or from the non-treated control for scab incidence. Aside from the three low rate treatments: (Captan 4L 1 qt/A, Prophyt 1 pt/A, and Captan 4L 1 qt/A + Prophyt 1 pt/A), all treatments were effective in reducing scab severity compared with the non-treated control. The addition of Prophyt to Captan did not reduce disease levels over those observed with Captan alone or vice versa.