Lasiodiplodia theobromae is a cosmopolitan pathogen geographically widespread in tropics and subtropics inciting economically important diseases on diverse plant genera. In the present study, Lasiodiplodia theobromae associated with nutmeg exhibiting die-back and declining symptoms was identified and characterized by adopting a polyphasic approach. The disease was characterized with the symptoms including general decline, water-soaking patches on branches and tree trunk, die-back of branches, necrotic lesions beneath water-soaked lesions and necrosis of vascular tissues. The isolates representing diverse nutmeg growing tracts were initially identified as Lasiodiplodia species based on macro- and micro-morphological characteristics. Subsequent analyses of internal transcribed spacer (ITS), partial elongation factor 1-alpha (EF1-α) and β-tubulin (β-tub) genes identified the pathogen as Lasiodiplodia theobromae. Pathogenicity studies were proved on nutmeg twigs and branches (in vitro) as well as on saplings (in vivo). The present investigation enunciated the association of Lasiodiplodia theobromae with die-back and decline of nutmeg employing a polyphasic approach which warrants further investigations on its spatio-temporal distribution, pathogen diversity, weather–host–pathogen interaction and formulating prospective disease management strategies.

可可毛二孢菌(Lasiodiplodia theobromae)是一种世界性病原体，广泛分布于热带和亚热带地区，可引发不同植物属的经济上重要的疾病。在本研究中，通过采用多相方法，鉴定并表征了与肉豆蔻相关的表现出枯萎和衰退症状的可可毛二孢。该病的特点是树体普遍衰弱，枝干出现水渍斑，枝条枯死，水渍下坏死病斑，维管束组织坏死。根据宏观和微观形态特征，代表不同肉豆蔻生长区的分离株最初被鉴定为毛二孢属物种。随后对内转录间隔区（ITS）、部分延伸因子1-α（EF1-α）和β-微管蛋白（β-tub）基因的分析确定该病原体为可可毛二孢菌（ Lasiodiplodia theobromae ） 。致病性研究已在肉豆蔻细枝和树枝（体外）以及树苗（体内）上得到证实。本研究采用多相方法阐明了可可毛二孢与肉豆蔻枯死和衰退之间的关联，这值得对其时空分布、病原体多样性、天气-宿主-病原体相互作用和制定前瞻性疾病管理策略进行进一步研究。