Abstract
THE Transactions for 1920 of the British Mycological Society published in July last are evidence of the increasing activities of the group of botanists whose work is amongst the fungi. The presidential address by Mr. Fetch deals with fungi parasitic on scale-insects, and includes an historical account of the growth of knowledge since the first record of a fungus growing parasitically on a scale-insect was made by Desmazières in 1848 at Caen, in Normandy. The list is now a long one, and will doubtless be further extended; and though the majority of scale-insect fungi are tropical, there is some work to be done on them in the British Isles. In the tropics enormous destruction of scale-insects is effected by these fungi, and, as some of the scale-insects are serious pests of economic plants, the suggestion naturally arose that the pests might be controlled by means of the entomogenous fungi. A special investigation was undertaken by the United States Bureau of Entomologv in Florida, but the results agree with those of other experiments, and Mr. Fetch affirms that after thirty years' trial there is no instance of the successful control of any insect by means of fungus-parasites. Prof. A. H. R. Buller describes the mechanism by means of which the common mould-fungus, Pilobolus, is able to shoot its spore-case, containing many thousands of spores, a distance of several feet. Sunlight striking obliquely on the protoplasm of the cell beneath the spore-case gives rise to a stimulus resulting in a movement which places the axis of the stalk on which the spore-case is borne in the line of the light-ray. The fungus may be described as having an optical sense-organ or simple eye which it uses for laying its gun in a definite direction. Pilobolus lives in fields on the dung of herbivorous animals, and by directing its guns towards the source of brightest light is enabled to shoot its sporangia into open spaces on to grass and other herbage. Herbivorous animals eat grass and sporangia together, and the spores are passed unharmed in the solid excreta in which they germinate.
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British Mycology. Nature 109, 154–155 (1922). https://doi.org/10.1038/109154b0
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DOI: https://doi.org/10.1038/109154b0