Epidemiology and Control of Vein Spot Disease of Pecan Caused by Gnomonia nerviseda. R. S. Sanderlin, Associate Professor, Louisiana State University, Pecan Research-Extension Station, Shreveport 71135. A. S. Hunt, Former Research Associate, Louisiana State University, Pecan Research-Extension Station, Shreveport 71135, and D. K. Babcock, Instructor, Department of Experimental Statistics, Louisiana State University, Baton Rouge 70893. Plant Dis. 67:1209-1213. Accepted for publication 2 May 1983. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-1209.

The incitant of vein spot disease of pecan, Gnomonia nerviseda, infected vascular tissue of the foliage and generally caused localized lesions. Infection frequently occurred at the junction of the petiolule to the rachis and at the base of the rachis. The disease caused premature loss of leaflets and compound leaves. Infection was initiated by ascospores that had been released after rainfall, primarily in May and June. No significant relationship was found between the height of the foliage above the ground and the number of infections. Of the fungicides labeled for use on pecan, benomyl was the most effective, followed by dodine, for control of vein spot. Fentin hydroxide provided little protection when disease development was severe. Trees treated with benomyl had significantly fewer lesions and less defoliation than untreated trees in a year of high vein spot severity.

Keyword(s): Carya illinoensis.