Characterization ofLasiodiplodiaspecies causing leaf blight, stem rot and fruit rot of fig (Ficus carica) in Malaysia

Abstract

AbstractFig (Ficus carica) is an exotic deciduous plant that is grown worldwide. Fungal diseases pose a major threat to fig plants, affecting their fruit quality and production. This study was conducted to characterize the fungal isolates associated with leaf blight, stem rot and fruit rot ofF.caricain Malaysia through morphological analysis, DNA sequencing, multigene phylogenetic analysis and pathogenicity tests. From September 2018 to March 2019, 30 blighted leaves and 30 rotted stems and fruits ofF.caricawere collected from several nurseries in Malaysia. Thirty fungal isolates that belonged toLasiodiplodia theobromae(27 isolates) andL. brasiliensis(three isolates) were identified based on morphological characteristics, comparison of DNA sequences and phylogenetic analysis of the internal transcribed spacer (ITS), elongation translation factor 1‐α (tef1‐α), β‐tubulin (tub2) and DNA‐directed RNA polymerase II subunit (rpb2). Among the 27 isolates ofL.theobromae, nine isolates were obtained from leaves, eight isolates from stems and 10 isolates from fruits, whereas the three isolates ofL.brasiliensiswere obtained from stems (two isolates) and a leaf (one isolate). The results of pathogenicity tests revealed thatL.theobromaeandL.brasiliensisisolates were responsible for leaf blight and stem rot ofF.carica, whereas fruit rot was caused byL.theobromaeisolates. The present study highlighted two different species,L. theobromaeandL.brasiliensis, as the causal agents of leaf blight and stem rot ofF.carica. Additionally,L.theobromaecaused fruit rot ofF.caricain Malaysia.