Susceptibility of pecan cultivars to Venturia effusa in Uruguay

Abstract

Pecan scab caused by Venturia effusa is the main crop disease affecting leaves and fruits, resulting in defoliation and yield and fruit quality losses. Recently, pecan groves expanded into Uruguay, Brazil and Argentina, where the temperate-humid climate is conducive for scab development. Chemical control is difficult given the height of adult trees which exceeds 20 m. Therefore, the strategy consists on selecting tolerant cultivars accompanied by cultural management aimed at providing a good ventilation and light interception. The objective of this work was to assess the susceptibility of pecan cultivars to Venturia effusa in the Uruguayan agroclimatic conditions. Disease severity index (DSI) in fruits and leaves were determined in 18 cultivars throughout four consecutive seasons. Most of the cultivars evaluated were classified as resistant with fruit disease severity index (DSIF) below 2.0, being Elliott and Sumner the most resistant ones (DSIF < 1.5) while Mahan was susceptible (DSIF > 3.0) and Apache and Wichita were very susceptible (DSIF > 4.5)

Keywords:

• Carya illinoinensis
• scab
• disease severity index
• tolerant cultivar
• scab symptoms

Acknowledgements

We are grateful to David Bianchi for his collaboration in this project.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was funded by The National Institute of Agricultural Research (Instituto Nacional de Investigación Agropecuaria –INIA, Uruguay) (Project INIA FR 25).