El-Hamalawi Z A, Stanghellini M E
Department of Plant Pathology, University of California, Riverside 92521.
Plant Dis. 2005 Jun;89(6):619-623. doi: 10.1094/PD-89-0619.
Fusarium crown and stem rot of lisianthus (Eustoma grandiflorum), caused by Fusarium avenaceum, is a destructive disease in California. The pathogen produces large masses of orangecolored macroconidia on stem lesions that extend up to 35 cm in length from the soil surface. Populations of macroconidia (97% viability) range from 1.1 × 10 to 1.9 × 10 per cm of infected stem tissue. An aboveground life stage for a soilborne pathogen could serve as a source for acquisition and aerial dissemination by adult shore flies, fungus gnats, and moth flies. Our results provide evidence that these three insects are attracted to and readily acquire (either externally and/or internally) macroconidia of F. avenaceum produced on naturally infected lisianthus stems and then disseminate acquired macroconidia to healthy plants, which subsequently died, or to an abiotic substrate (Komada's medium, KM). The high percentage of transmission, as evidenced by both the number of KM plates colonized by the pathogen (up to 68.5% within 18 h) and the number of plants infected (75% within 4 days), reflects the efficiency of these insects as vectors.
由燕麦镰刀菌引起的洋桔梗（Eustoma grandiflorum）镰刀菌冠腐和茎腐病，是加利福尼亚州一种具有毁灭性的病害。病原菌在茎部病斑上产生大量橙色大分生孢子，病斑从土壤表面向上延伸可达35厘米长。每厘米受感染的茎组织上大分生孢子的数量（活力为97%）在1.1×10至1.9×10之间。土壤传播病原菌的地上生活阶段可能成为成年岸蝇、蕈蚊和蛾蠓获取和空气传播的来源。我们的结果表明，这三种昆虫会被自然感染洋桔梗茎上产生的燕麦镰刀菌大分生孢子吸引，并很容易获取（外部和/或内部）这些孢子，然后将获取的大分生孢子传播到健康植株上，这些植株随后死亡，或者传播到非生物基质（小田培养基，KM）上。病原菌在KM平板上定殖的数量（18小时内高达68.5%）和感染植株的数量（4天内为75%）所证明的高传播率，反映了这些昆虫作为传播媒介的效率。
