Botrytis cinerea is an important plant pathogen that can infect a wide range of hosts and cause serious losses in many crops. In Orchidaceae, gray mold is one of the main diseases caused by fungi, commonly associated to flower spots. Here, we described a new disease caused by B. cinerea on Maxillaria richi, an orchid native from Ecuador and marketed in Brazil. Samples of M. richii with unusual defoliation symptoms were observed in a greenhouse. The diseased material was used to isolate the pathogen. The morphological and molecular data revealed that the isolates belong to B. cinerea. The pathogenicity test confirmed that B. cinerea is the etiological agent of the defoliation. To our knowledge, this is the first report of B. cinerea causing basal leaf rot and defoliation on a member of Orchidaceae.

Botrytis cinerea是一种重要的植物病原体，可以感染广泛的宿主并导致许多作物的严重损失。在兰科，灰霉病是由真菌引起的主要疾病之一，通常与花斑有关。在这里，我们描述了由B. cinerea对Maxillaria richi引起的一种新疾病，Maxillaria richi是一种原产于厄瓜多尔并在巴西销售的兰花。在温室中观察到具有异常落叶症状的M. richii样品患病材料用于分离病原体。形态学和分子学数据表明分离株属于灰霉病菌。致病性试验证实B. cinerea是落叶的病原体。据我们所知，这是B. cinerea引起兰科植物基叶腐烂和落叶的首次报道。