Mango malformation: etiology, symptoms, distribution and cultivar susceptibility in the Dominican Republic

Abstract

Mango malformation disease (MMD) caused by Fusarium species has become an important disease of mango ( Mangifera indica L.) orchards worldwide. In the Dominican Republic, MMD was first observed in 2008 in orchards of Azua and Peravia provinces, with incidence of up to 50%. This study aimed to estimate the malformation prevalence and distribution in the main mango growing areas of the Dominican Republic and to assess the susceptibility of six commercial cultivars commonly grown in this country. Mango malformation was found in 18 out of 58 orchards, all located in Peravia and Azua. Peravia showed the highest incidence, with values of up to 75% (2013) and 87.5% (2014), and the interpolative analysis made with ArcGIS showed this province as being more inductive for Fusarium spp. occurrence. Pathogenicity tests were conducted in 2013 and 2014 on 10-month-old healthy mango plants per cultivar. Inoculation was done by infiltration of Fusarium pseudocircinatum and Fusarium decemcellulare conidial suspensions into the vegetative apical buds, singly and in combination. In inoculated plants, symptoms such as loss of apical dominance, excessive proliferation of apical or axillary buds with thickened stems, and reduction of leaf lamina were associated with F. pseudocircinatum. In addition to these symptoms, leathery protuberant buds and eventual death of infiltrated plants were associated with F. decemcellulare, singly or coinoculated with F. pseudocircinatum. Based on a disease severity index (DSI), “Tommy Atkins” was tolerant (DSI = 7.8%) and “Puntica” and “Banilejo” were highly susceptible (DSI = 22% and 28.5%).