Skip to main content
ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #360311

Research Project: Mitigating Alternate Bearing of Pecan - Bridge Project

Location: Fruit and Tree Nut Research

Title: Efficacy of agricultural oil and fungicide combinations as a late dormant treatment for control of peach scab in Georgia, 2015

Author
item Brannen, Philip - University Of Georgia
item Bock, Clive
item Hotchkiss, Michael - Mike

Submitted to: Plant Disease Management Reports
Publication Type: Trade Journal
Publication Acceptance Date: 2/11/2016
Publication Date: 3/7/2016
Citation: Brannen, P.M., Bock, C.H., Hotchkiss, M.W. 2016. Efficacy of agricultural oil and fungicide combinations as a late dormant treatment for control of peach scab in Georgia, 2015. Plant Disease Management Reports. 10:STF014.

Interpretive Summary: Fungicides were evaluated for control of scab in a late-ripening peach experimental block (‘Flameprince’) located at Byron, GA. Treatment regimens included a non-treated control, a standard spray program of Bravo/Bravo/Sulfur, and eight late dormant sprays comprised of various fungicides with and without oil. Scab incidence (percent infected fruit) and severity (lesions per fruit) were recorded on the day of harvest. Disease pressure was low and there was no difference in efficacy between fungicides applied with or without oil. The standard spray program of Bravo/Bravo/Sulfur provided the greatest scab suppression. The Abound treatment did provide substantive control of scab with a dormant application. Whether this could be of value if incorporated in a full peach scab spray regiment remains to be seen.

Technical Abstract: Fungicides were evaluated for control of scab in a late-ripening peach experimental block (‘Flameprince’) located at the USDA Research Station in Byron, GA. Chemical formulations were applied with an airblast sprayer (100 gal/A spray volume) at the late dormant stage, with the exception of a standard treatment regimen applied throughout the growing season (petal fall, shuck split stages, and subsequent cover sprays). Treatment regimens included a non-treated control, a standard spray program of Bravo/Bravo/Sulfur, and eight late dormant sprays comprised of various fungicides with and without oil. Five replications of each treatment were applied to a randomized complete block design, with each plot consisting of four trees; the outer two trees in each plot were not utilized for ratings. An unsprayed guard row was left between each treatment row. All orchard cultural management practices were in keeping with peach production methods commonly practiced throughout the Southeast. At full maturity, 40 fruit were harvested from each plot for scab assessments (30 June). Scab incidence (percent infected fruit) and severity (lesions per fruit) were recorded on the day of harvest. Disease pressure was low in this trial, and there was no difference in efficacy between fungicides applied with or without oil. The standard spray program of Bravo/Bravo/Sulfur provided the greatest scab suppression. Previous trials conducted on almonds in California between 2011 and 2014 concluded that single application late dormant sprays of Bravo (chlorothalonil) were more effective at suppressing inoculum in the spring when applied with oil. Though we did not see a strong translation of this information to the peach scab system, the Abound treatment did provide substantive control of scab with a dormant application. Whether this could be of value if incorporated in a full peach scab spray regiment remains to be seen.