Identification of pathogen species causing brown rot of peaches in Illinois and evaluating efficacy of potential fungicides for managing the disease

Seitz, Harrison

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https://hdl.handle.net/2142/117849 Copy

Description

Title

Identification of pathogen species causing brown rot of peaches in Illinois and evaluating efficacy of potential fungicides for managing the disease

Author(s)

Seitz, Harrison

Issue Date

2022-12-09

Director of Research (if dissertation) or Advisor (if thesis)

• Babadoost, Mohammad
• Miller, Andrew N

Committee Member(s)

• Athey, Kacie J
• Mideros, Santiago X

Department of Study

Crop Sciences

Discipline

Crop Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• Monilinia
• brown rot
• fungicides
• peaches

Abstract

Brown rot, caused by Monilinia spp., is one of the most important fungal diseases of peach in Illinois. To our knowledge, no research has been conducted in Illinois on the occurrence and management of brown rot disease of peach or other stone fruit crops in Illinois. The objectives of this study were to: (i) conduct orchard surveys to assess incidence of brown rot disease in commercial peach orchards in Illinois, (ii) identify fungal pathogens causing brown rot disease, (iii) evaluate variation among the pathogen isolates, and (iv) evaluate the efficacy of eleven registered potential fungicides for managing brown rot of peach in the orchard. Orchard surveys were conducted in 2020, 2021, and 2022 to assess occurrence of blossom blight, shoot blight, and fruit rot caused by Monilinia spp. in commercial peach orchards in Illinois. No blossom blight or shoot blight was observed. Results showed 9 of 14, 4 of 8, and 6 of 13 orchards had symptomatic brown rot fruits in 2020, 2021, and 2022, respectively. Symptomatic fruits were collected from peach cultivars Bounty, Carolina Belle, Contender, Fayette, Loring, Redhaven, Starfire, and an unknown cultivar in eight different orchards throughout the state. No infection was detected in cultivar July Prince. Infected fruit tissues were cultured on potato dextrose agar medium, and the pathogens were isolated. Based on the cultural characteristics and sequences of the ITS region, 127 of 129 collected isolates were identified as Monilinia fructicola (Winter) Honey, and two isolates were identified as M. laxa (Aderhold & Ruhland) Honey. Fungicide sensitivity of Monilinia fructicola isolates was conducted in the laboratory using eleven fungicides, including azoxystrobin (Abound 2.08SC), captan (Captan 80WDG), fenhexamid (Elevate 50WDG), trifloxystrobin (Flint Extra 4.05E), penthiopyrad (Fontelis 1.67SC), difenoconazole + cyprodinil (Inspire Super 2.82SC), fluopyram + tebuconazole (Luna Experience 3.34SC), fluopyram + trifloxystrobin (Luna Sensation 4.20SC), fluxapyroxad + pyraclostrobin (Merivon 4.18SC), propiconazole (Tilt 3.6EC), and thiophanate-methyl (Topsin-M 70WP). The EC50 of Abound, Captan, Flint Extra, and Fontelis for the colony development of the isolates were significantly (P = 0.05) higher than the other fungicides tested. Field trials were conducted at the University of Illinois Fruit Research Farm in Urbana, IL on ‘Redhaven’ and ‘Contender’ peaches in 2021 and 2022, to evaluate efficacy of the above-mentioned fungicides for managing brown rot disease. Trees were sprayed with fungicides at 10- and 14-day intervals from petal fall until two weeks to harvest. In 2021, incidence of symptomatic fruits was significantly (P = 0.05) higher in untreated plots than treated plots. In 2022, only nine fruits of ‘Redhaven’ with brown rot symptoms were observed, and there was no fruit of ‘Contender’ with brown rot symptoms. Luna Experience 3.34SC, Luna Sensation 4.20SC, and Merivon 4.18SC were the most effective fungicides for management of brown rot and other summer diseases of peach.

Graduation Semester

2022-12

Type of Resource

Thesis

Copyright and License Information

Copyright 2022 Harrison Seitz

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