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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #394682
Research Project: Healthy, Sustainable Pecan Nut Production

Location: Fruit and Tree Nut Research

Title: Efficacy of new fungicides for control of brown rot of peach in middle Georgia, 2021

Author
item BRANNEN, PHILLIP M. - University Of Georgia
item BREEDEN, SHANE - University Of Georgia
item SANDERS, W. - University Of Georgia
item RIOS, T. - University Of Georgia
item CHEH, A. - University Of Georgia
item Bock, Clive

Submitted to: Plant Disease Management Reports
Publication Type: Research Technical Update
Publication Acceptance Date: 7/18/2022
Publication Date: 8/1/2022
Citation: Brannen, P., Breeden, S., Sanders, W., Rios, T., Cheh, A., Bock, C.H. 2022. Efficacy of new fungicides for control of brown rot of peach in middle Georgia, 2021. Plant Disease Management Reports. Vol 16:PF031.

Interpretive Summary: Pre-harvest fungicides were evaluated for control of brown rot on peach. Treatments were an untreated control, and the fungicides Merivon as the chemical standard, Merivon (first application) followed by Cevya, Cevya, Indar 2F, Luna Flex, Luna Sensation, or Inspire Super. The Merivon, Luna Flex, and Luna Sensation products provided post-harvest control of brown rot. The use of Merivon, as well as other pre-mix products, in the first pre-harvest application followed by a a second pre-harvest application of other fungicides to which resistance occurs has consistently provided control that is equivalent to that of the use of Merivon or similar products in both applications. The results indicate that even if certain fungicides have lost some efficacy due to resistant populations of Monilinia fructicola (cause of brown rot) they can still be effective as a second spray. The reason for this is not known, but should be further investigated.

Technical Abstract: Pre-harvest fungicides were evaluated for control of brown rot on 19 and 26 Jul (pre-harvest sprays). Treatments were an untreated control, Merivon (fluxapyroxad + pyraclostrobin) as the chemical standard, Merivon (first application) followed by Cevya (mefentrifluconazole; second application), Cevya (mefentrifluconazole), Indar 2F (fenbuconazole), Luna Flex (fluopyram + difencaonazole), Luna Sensation (fluopyram + trifloxystrobin), and Inspire Super (cyprodinil + difenoconazole). The Merivon, Luna Flex, and Luna Sensation products displayed better overall post-harvest control of brown rot. Of the products containing demethylation inhibitor fungicides (DMIs), three out of four performed poorly. Though Luna Flex contains a DMI fungicide, the SDHI component may have provided the efficacy observed. Demethylation inhibitor (DMI) resistance has been confirmed at this site in the past, and the relatively poor performance of the DMI fungicides Cevya, Indar, and Inspire Super could be related to resistance in the Monilinia fructicola population at the site. The use of Merivon, as well as other SDHI/QoI pre-mix products, in the first pre-harvest application followed by a DMI in the second pre-harvest application has consistently provided control that is equivalent to that of the use of Merivon or similar products in both applications – even where resistance to DMI fungicides is observed. The results indicate that DMIs can still be utilized where resistant populations of Monilinia fructicola are observed, if applied after an SDHI/QoI product. The reason for this is not known, but should be further investigated.