First report of greenhouse tomato wilt caused by Plectosphaerella cucumerina in China.
In May 2011, root rot and plant wilt were observed on tomato (cultivars Jinguan No. 5 and Meina) plants in 26 commercial greenhouses in Huludao city, Liaoning Province, China. Disease incidence was 30-95%. At the beginning of fruit set, symptoms consisted of chlorosis of lower leaves and lack of turgidity in young leaves. Severely affected plants were wilted and stunted as the fruit approached maturity. Primary and secondary roots became necrotic with few fine feeder roots. Twenty axenic cultures were obtained from single conidia of the isolates. Colonies were buff or salmon pink, moist, and had appressed, slimy mycelium. Aerial mycelium was sparse with simple or branched conidiophores. Conidia were 4.0-8.9 × 2.0-4.0 µm in size, aggregated in slimy heads, hyaline ellipsoidal and ovoid, smooth, and 0- to one-septate. Conidia were borne on phialides that were 6.3-24.3 × 1.4-3.3 µm in size. These characteristics are typical of P. cucumerina [Monographella cucumerina]. This is thought to be the first report of P. cucumerina causing tomato wilt in China.