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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #384200

Research Project: Healthy, Sustainable Pecan Nut Production

Location: Fruit and Tree Nut Research

Title: Seasonal dynamics of conidia production of Venturia effusa from lesions of scab on pecan shoots

item Bock, Clive
item Adams, Cody
item Hotchkiss, Michael - Mike
item RAO, JAYA - Macon State College

Submitted to: American Phytopathological Society Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 5/25/2021
Publication Date: 10/1/2021
Citation: Bock, C.H., Adams, C.H., Hotchkiss, M.W., Rao, J. 2021. Seasonal dynamics of conidia production of Venturia effusa from lesions of scab on pecan shoots. American Phytopathological Society Annual Meeting. Vol 110:S2.150.

Interpretive Summary:

Technical Abstract: Scab (caused by Venturia effusa) is the most important disease of pecan in the southeastern U.S. The role and characteristics of conidia production from lesions on the shoots is poorly understood but may be important to infection of young leaves and fruit early in the season. The objective was to characterize the seasonal trends of spore production from scab lesions on pecan shoots. The experiment was conducted on cvs. Wichita, Cherokee and Apache in orchards in Georgia, the U.S. Samples of shoots with scab lesions developing each season were collected every two weeks for 12-month periods starting in late May-June of each season from 2018 through 2020. The number of lesions/shoot section varied with sample (14.2 to 861.0 lesions/section) but conidia production showed a similar pattern each season on all cultivars with most conidia per lesion produced on new, young lesions formed from late Jun to Sep (up to 31,690 conidia/lesion, depending on season and cultivar). Generally fewer conidia were produced from Oct to May (up to 4,384 conidia/lesion, depending on season and cultivar, but most often much less). There was evidence of a slight increase in spore production on the previous season’s shoot lesions in the spring (Mar-Apr) coinciding with the period of pecan bud break and leaf development, but the increase was small. These results provide further evidence for a role of conidia produced from overwintering shoot lesions as a source of infection for newly-emerged foliage early in the season.