D. O. Morgan

The Potato-Root Eelworm in Lincolnshire

In 1924, Morgan visited South Lincolnshire to investigate the part played by the potato-root eelworm ( Heterodera schachtii ) in the serious failure of the local potato crop: a note on the investigation appears in this Journal (1925, p. 185). A second visit was made in 1925, as a result of which certain conclusions regarding manuring and the rotation of crops were put forward (this Journal, 1926, p. 49). Towards the end of 1925 the second writer (Peters) made a hurried survey with the object of seeking a possible correlation between the distribution of eelworm cysts and the hydrogen ion concentration of the soil. Such a correlation was actually demonstrated (this Journal, 1926, p. 87) in the case of a selected field for which Morgan had complete data of cyst-counts. The question thus arose as to whether any clear correlations should be shown to exist between the three factors: concentration of cysts, pathological condition of the crop, and reaction of the soil. In other words, was the eelworm associated with the damage? and was it controlled (and therefore controllable) by the effective acidity of the soil? To decide these questions might be a matter of considerable importance, particularly if the eelworm was found to be responsible for the damage, for affirmative answers would open the way to effective treatment, by the adequate liming of soils for instance.

Some observations on gape-worm in poultry and game birds.

In the literature which deals with the gape-worm, Syngamus trachea , found commonly in England, its presence has been recorded from a fair variety of birds. It has been found several times in the starling—Nathusius (1837), Megnin (1883) and, among others, by Lewis (1925). Dujardin records having found it in the magpie, Corvus pica , (1845) Megnin (1883) found it in the swift ( cypselus apus ), green woodpecker ( Picus viridis ), black stork ( Ciconia nigra ) and in the pheasant and partridge. It has further been recovered by Lewis (1925) from the rook ( Corvus frugilegus ), thrush ( Turdus musicus ) and jay ( Garrulus glandarius ), while in the Ministry of Agriculture Leaflet No. 58, the sparrow and linnet are also cited as being occasional hosts, and Walker (1886) has found it in the robin. The present writers have found a closely related species, S. merulae (Baylis, 1926) in the tracheae of four blackbirds which came into the laboratory during the summer. Though these birds seem to be only occasional hosts, most of the authors stating that the infections occurred only in young birds while the adults are comparatively free from this worm, yet a high percentage of young birds are frequently found to be carrying this parasite: for instance, Elton and Buckland (1928) in a batch of 33 young rooks obtained from the Oxford district, found 31 infected, while of 8 old birds only four were infected and these only lightly. Lewis in 1926 found 35 per cent. of a sample of starlings infected but he did not notice the age of the birds. Morgan examined two nests of young starlings and found that all of one batch harboured S. trachea . He suggests that they may have become infected from the earthworms brought in by the parent birds as food.

A New Nematode Species of the Genus Viannaia from the Mole ( Talpa europœa ).

A Few specimens of the Trichostrongyle, described in this paper, were obtained from the intestine of moles caught on the experimental farm of the Institute of Agricultural Parasitology, St. Albans.