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United States Department of Agriculture

Agricultural Research Service

Research Project: PECAN CULTIVATION AND DISEASE MANAGEMENT

Location: Fruit and Nut Research

Title: Efficacy of petal fall and shuck split fungicides for control of scab on peach in middle Georgia, 2012

Authors
item Brannen, P -
item Bock, Clive
item Hotchkiss, Michael

Submitted to: Plant Disease Management Reports
Publication Type: Other
Publication Acceptance Date: August 30, 2013
Publication Date: August 30, 2013
Citation: Brannen, P.M., Bock, C.H., Hotchkiss, M.W. 2013. Efficacy of petal fall and shuck split fungicides for control of scab on peach in middle Georgia, 2012. Plant Disease Management Reports. 7:STF022 http://www.plantmanagementnetwork.org/pubtrial/pdmr/.

Interpretive Summary: Fungicides were evaluated for control of scab in a mid-ripening experimental peach block (‘Flameprince’) located at the USDA-ARS Fruit and Tree Nut Research Laboratory (Byron, GA). Formulations were applied weekly from 3 Apr to 22 Jun. Treatment regimens included a non-treated control, two applications of Bravo Weather Stik FL (petal fall and shuck split) followed by Yellow Jacket Sulfur cover sprays (chemical standard), two applications each at petal fall and shuck split of Bravo, Abound, Yellow Jacket Sulfur, Orbit and Topsin M. The applications of individual fungicides at the petal fall/shuck split phenologies were utilized to determine the contribution to disease control afforded by application made during that specific timeframe, as well as the efficacy of the fungicides for scab management. The full-season spray regimens were effective for suppression of scab, but two applications of Abound at petal fall and shuck split resulted in equivalent control to that of a full-season standard program. Applications of fungicides at petal fall and shuck split provided a sufficient means of determining fungicidal efficacy for scab management.

Technical Abstract: Fungicides were evaluated for control of scab in a mid-ripening experimental peach block (‘Flameprince’) located at the USDA-ARS Fruit and Tree Nut Research Laboratory (Byron, GA). Chemical formulations were applied at each application date: 3 Apr (petal fall to 1% shuck split), 10 Apr (shuck split to 10% shuck off), 27 Apr, 11 May, 18 May, 25 May, 1 Jun, 8 Jun, 15 Jun, and 22 Jun (cover sprays). Treatment regimens included a non-treated control, two applications of Bravo Weather Stik FL (petal fall and shuck split) followed by Yellow Jacket Sulfur cover sprays (chemical standard), two applications each at petal fall and shuck split of Bravo, Abound, Yellow Jacket Sulfur, Orbit and Topsin M. The applications of individual fungicides at the petal fall/shuck split phenologies were utilized to determine the contribution to disease control afforded by application made during that specific timeframe, as well as the efficacy of the fungicides for scab management. Scab symptoms can develop throughout the season from inoculum, but a critical peak in spore production occurs around the petal fall and shuck split phenological stages. Scab severity was low to moderate on the non-treated control in this trial; the full-season spray regimens were effective for suppression of scab, but two applications of Abound at petal fall and shuck split resulted in equivalent control to that of a full-season standard program. For Bravo, the petal fall and shuck split applications significantly reduced scab severity as well, but Abound provided numerically superior scab control. Sulfur, Topsin M, and Orbit were not as efficacious as either Bravo or Abound. Applications of fungicides at petal fall and shuck split provided a sufficient means of determining fungicidal efficacy for scab management.

Last Modified: 4/23/2014
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