In 2019, wilt and sudden death were observed on Artocarpus heterophyllus (jackfruit). Identification was performed by sequence analysis of the concatenated β-tubulin and ITS gene regions. Sequencing of the PCR product confirmed this pathogen was Ceratocystis fimbriata sensu stricto. This is the first report of C. fimbriata causing sudden death disease in A. heterophyllus in Indonesia and worldwide.

Wilt disease with unknown etiology causes mass mortality in commercial Acacia mangium nurseries in South Sumatra. This pathogen induces symptoms of chlorosis in the lower leaves and develops into the shoots; subsequently, the plants wither and die. This research identifies the pathogenic species causing this wilt disease and to assess its pathogenicity or virulence. Fifteen isolates of Fusarium oxysporum with varying colony sizes and color pigments were recovered from symptomatic A. mangium seedlings. The pathogenicity test showed that all isolates could infect plants with wilt severity reaching 80%, and the pathogen was verified as causing vascular disease. Koch’s postulate was verified by re-isolating the F. oxysporum isolates. The pathogen was confirmed by observing the morphological characters and elongation factor 1-α (tef1-α) gene sequences as F. oxysporum.

Abstract. Soleha S, Muslim A, Suwandi S, Kadir S, Pratama R. 2021. Host range studies of Fusarium oxysporum, causal agent of seedling wilt disease of Acacia mangium. Biodiversitas 23: 25-32. Fusarium oxysporum is a serious pathogen that causes severe wilt disease in commercial nurseries of Acacia mangium in South Sumatra, Indonesia. This study aimed to investigate the host range of F. oxysporum as a nursery wilt pathogen in A. mangium and several forest and industrial plants. Three isolates of F. oxysporum with different translation elongation factor (tef 1-a) sequences were tested for pathogenicity on different fabaceae family plants and the growth of population was also observed. The results showed that  all the three isolates were able to infect all the tested plants with different reactions of wilt disease. The Acacia crassicarpa and Falcataria moluccana were highly susceptible; Archidendron pauciflorum, Leucaena leucocephala, and Parkia speciosa were moderately vulnerable and Acacia auriculiformis was moderately resistant. The pathogen population in A. crassicarpa and F. moluccana grew rapidly along with the increase in disease scores, while  in L. leucocephala it was moderate, and slow in A. pauciflorum, P. speciosa and A. auriculiformis plants. In conclusion, F. oxysporum pathogen, which was isolated from A. mangium, has a wide range of hosts in the fabaceae family.