|Current status of mango malformation disease and its causal agents in Malaysia.
Nik Mohamed Nor: Universiti Sains Malaysia
<div>Mango malformation disease (MMD) was first reported in India in 1891 and has progressively spread to other mango growing countries across different continents. MMD is an economically important disease to the mango industries as it infects inflorescences and vegetative parts of mango tree. The interruption on the plant canopy and floral developments reduces the number of fruit production. More than one species of <em>Fusarium</em> was reported to be the causal agent of MMD from different regions. In 2013, <em>Fusarium proliferatum</em> was reported to be associated with MMD in Malaysia. However, pathogenicity was not performed, thus the causal agent of mango malformation disease in Malaysia remains unclear. The objectives of this study are to conduct a field survey on the occurrence of MMD, and to determine the causal agent of MMD in Malaysia. A survey on the occurrence of MMD in peninsular Malaysia was conducted focusing on mango orchards and nurseries. Throughout the peninsular Malaysia, only two mango orchards were found to be infected with this disease at inflorescence stage. A total of 83 isolates of <em>Fusarium</em> spp. were collected from the malformed tissue. The identification of <em>Fusarium</em> was based on the morphology and molecular methods. There were three dominant species isolated from the malformed inflorescences which were <em>F. mangiferae</em>, <em>F. concentricum</em>, and <em>F. proliferatum</em>. The pathogenicity of these isolates was being conducted on the inflorescence tissue and 6 month old mango seedlings of the Chokkanan variety. Our preliminary results showed that <em>F. proliferatum</em> causes the mango flowers becoming necrotic and fall off. The malformation symptoms have not yet been observed from the pathogenicity test. This study will resolve the problem on determining the causal agent of MMD in Malaysia.</div>