Abstract
In the field the bulb of Allium Barkeri REGEL is subjected to attack by a fungus. Its outer scale is altered into a black membrane, on account of which market value of the crops is reduced. In the membrane a dense ramification of dark mycelia is observed. Kept in a moist place, it gives rise to brown apothecia which are funnel-, cup- or dish-shaped, having smooth stipes of variable lengths. Clavate asci measure 120-190×8-13μ in dimension and contain eight spores, which are 1-2 celled, being 13.3-19.0×5.7-6.7μ in size.
The fungus may develop profusely on agar media of various kinds. On potato agar it produces white, floccose aerial mycelium and tough, black-brown thallus. After about four weeks it forms black, stromatoid crusts on the substratum. Apothecia arise from these crusts. Optimum temperature for mycelial growth is 20-25°C. Conidial stage is unknown.
The fungus is considered to be a species of Helotium, but to decide whether it is new to science or not, further investigations are required. Inoculation with mycelium and ascospores resulted in blackening of the scales, so that our fungus is recognized to be the cause of the disease under consideration.
