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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #321299
Title: Efficacy of Prophyt plus Captan when combined for control of peach scab in Georgia, 2014

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: 8/14/2015
Citation: Brannen, P.M., Bock, C.H., Hotchkiss, M.W. 2015. Efficacy of Prophyt plus Captan when combined for control of peach scab in Georgia, 2014. Plant Disease Management Reports. 9:STF008.

Interpretive Summary: Fungicides were evaluated for control of scab in an experimental peach block (‘Julyprince’) located in Byron, GA. Chemical formulations were applied at petal fall and shuck split with two subsequent cover sprays. Treatment regimens included: Prophyt, Captan 4L and Captan 4L + Prophyt (two treatments were applied at different rates for each), Bravo Weather Stik, Abound, and a non-treated control. At full maturity, 40 fruit were harvested from each plot for scab assessments. Scab incidence (percent infected fruit) and severity (lesions per fruit) were recorded on the day of harvest. 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 reduction in scab incidence or severity with the Prophyt and Captan combinations compared with solo Captan applications (where Captan was applied at the same rate solo as in the tank mix). However, the high rate of Captan was as successful at reducing scab incidence and severity as the industry standards Abound and Bravo Weather Stik.

Technical Abstract: Fungicides were evaluated for control of scab in an experimental peach block (‘Julyprince’) 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), 2 Apr (shuck split to 10% shuck off) and two subsequent cover sprays on 10 April and 28 April. Treatment regimens included: Prophyt, Captan 4L and Captan 4L + Prophyt (two treatments were applied at different rates for each), Bravo Weather Stik, Abound, and a non-treated control. Four replications of each treatment were assigned to a randomized complete block design, with each plot consisting of four 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 for scab assessments (25 Jun). Scab incidence (percent infected fruit) and severity (lesions per fruit) were recorded on the day of harvest. 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 reduction in scab incidence or severity with the Prophyt and Captan combinations compared with solo Captan applications (where Captan was applied at the same rate solo as in the tank mix). However, the high rate of Captan was as successful at reducing scab incidence and severity as the industry standards Abound and Bravo Weather Stik.