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ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Plant Pathology Research » Research » Publications at this Location » Publication #413173

Research Project: Mitigation of Domestic, Exotic, and Emerging Diseases of Subtropical and Temperate Horticultural Crops

Location: Subtropical Plant Pathology Research

Title: Feedback on the SAPPA UFS Pecan Scab Roadshow through the eastern pecan growing regions of South Africa

item Bock, Clive
item MARAIS, GERT - University Of The Free State

Submitted to: Trade Journal Publication
Publication Type: Trade Journal
Publication Acceptance Date: 2/28/2024
Publication Date: 3/10/2024
Citation: Bock, C.H., Marais, G.J. Feedback on the SAPPA UFS Pecan Scab Roadshow through the eastern pecan growing regions of South Africa. Trade Journal Publication. SA Pecan. 97:6-9. 2024.

Interpretive Summary:

Technical Abstract: Scab on pecan occurs in eastern South Africa. Visually, the disease symptoms are very similar to scab (caused by Venturia effusa) in the USA. It is highly likely V. effusa is involved in the disease in South Africa, but there are reports that other fungal organisms, particularly Cladosporium spp. are also found consistently associated with the lesions, suggesting the disease may be more of a complex on pecan in South Africa. Methods used to control scab caused by V. effusa are discussed, including timing and frequency of fungicide sprays, the sprayer type and settings, the fungicide chemistry used and the risk of fungicide resistance, cultural aspects affecting scab, and the use of resistant cultivars. It is noted that in scab prone areas the disease will always be a risk on susceptible cultivars, and the possibility of even resistant cultivars failing must be considered due to adaptability of the fungus. Clearly establishing the aetiology of the disease will help guide appropriate treatments.