First report of dieback in jackfruit (Artocarpus heterophyllus) caused by Lasiodiplodia theobromae in Nayarit, Mexico

Background/Objective. Jackfruit (Artocarpus heterophyllus) is an economically important fruit for Nayarit, accounting for over 90% of the national crop. Branch dieback has been detected in jackfruit trees in recent years, so the objective of this study was to identify the causative agent of branch dieback in A. heterophyllus in the state of Nayarit, Mexico. Materials and Methods. From a collection of Lasiodiplodia theobromae strains from commercial orchards of jackfruit, mango (Mangifera indica), soursop (Annona muricata), avocado (Persea americana), and Persian lime (Citrus latifolia) in Nayarit, the pathogenicity of L. theobromae was evaluated on one-year-old jackfruit trees. The isolates were molecularly identified by sequencing the internal transcribed spacer (ITS5 and ITS4 primers) and translation elongation factor 1-alpha (TEF1; primers EF-728/EF-986) regions. Results. All isolates were pathogenic to jackfruit. LY1 and LG4, from jackfruit and soursop, respectively, showed high aggressiveness on branches. Dieback symptoms were evident two months post-inoculation, with shoot rot, internal necrotic lesions, and bark fissures on branches and stems, as well as tree death. The ITS and EF1-α sequences of isolates recovered from pathogenicity testing showed 99–100% similarity to previously published sequences for L. theobromae in GenBank. Conclusion. This is the first report of L. theobromae as a causal agent of dieback of jackfruit A. heterophyllus in Nayarit, Mexico.