Symptomatological Characterization and Epidemiological Considerations of Persian Lime Death Syndrome in Commercial Orchards

Abstract

The Persian lime death syndrome (PLDS), also known as wood pocket, has reemerged as a serious problem affecting Persian lime production in the Martinez de la Torre region of Veracruz, causing tree mortality in commercial orchards. This study aimed to characterize the symptom progression and epidemiology of the syndrome in commercial orchards in the region, with the goal of developing a systematic description to better understand its etiology and facilitate its diagnosis. The incidence of this abiotic disease was assessed through visual inspection, recording the typical foliar chlorosis in all trees over a four-month period. Epidemic dynamics were analyzed by fitting the data to the flexible Weibull model ( y = 1 − [t/ b ] c ), estimating initial incidence ( y ₀), final incidence ( y f ), disease progress rate ( b −1 ), and the area under the disease progress curve (AUDPC). The spatial pattern of the disease was studied using interpolative geostatistical maps and by calculating dispersion indices (variance-to-mean ratio, Lloyd’s index, and Morisita’s index). At the subregional level, PLDS was characterized by applying multivariate analysis to a matrix comprising 10 orchards and 12 variables. Results showed that disease incidence ranged from 15% to 68%, with epidemic parameters also varying significantly among orchards (1/ b = 0.000041 - 1.69, p = 0.05; AUDPC = 7.09 - 41.06; y f = 15% - 68%). In the 10 orchards evaluated, a predominantly random spatial pattern was observed (V/M = 0.7 - 1.1, LIP = 0.7 - 1.2 y Ig = 0.7 - 1.3). The knowledge generated in this study may be useful for designing targeted management strategies for this abiotic disease, taking into account the subregional characteristics of the state of Veracruz.