In the Chambezi-Luapula area of the Northern Province of Northern Rhodesia, 2,575 Africans were examined for intestinal helminths and 2,017 for urinary helminths. The examinations were carried out in situ in the native villages in widespread localities representing different topographical parts of the area.

The average infection rates of the helminthic infections found were as follows: hookworm, 52.2%; Strongyloides, 13.3%; Ascaris lumbricoides, 3.7%; Enterobius vermicularis, 0.85%; Trichuris trichiura, 0.3%; Trichostrongylus sp., 0.1%; Schistosoma haematobium, 14.7%; S. mansoni, 6.99%; Hymenolepis nana, 0.09%; H. diminuta, 0.04%; Taenia sp., 0.04%.

The survey revealed regions or foci of relatively high and relatively low incidence in the case of each of the major species. The relationship of this to topographical and other factors is discussed.

Examination of 459 Africans for Mf. bancrofti revealed three positives, but none of these had definitely contracted the infection in N. Rhodesia. Mf. Perstans was found in 5.4% of those examined; this infection is endemic in the country.

A brief description has been given in an earlier paper (Goodey, 1943) of damage to tulip bulbs caused by the stem and bulb eelworm, Anguillulina dipsaci. In April, 1944, an opportunity arose, through the good offices of Mr. J. Oldnall Page, of Spalding, Lincs., of visiting a field in his district, in which eelworm-affected tulips were growing. Two of the varieties inspected were in flower and the other two were in an advanced bud condition. All four varieties exhibited marked symptoms of attack, and in the case of two of them in which there were a considerable number of plants, the damage caused to the blooms would entail a distinct financial loss to the grower. The largest planting consisted of the variety “ Rijnland,” the next largest was the variety “Wonderful.” In addition to these there were smaller plantings of “ William Copland ” and “ Mrs. Farncombe Sanders.” In all four varieties evidences of attack were apparent on leaves, stems and flowers and, in general, the writer can confirm the findings of Chitwood and Machmer (1942) on the symptoms manifested by the growing plant. They mention longitudinal splitting of leaf, flower-stem and corolla. It may be well, however, to attempt a more detailed description of the chief symptoms and types of lesion shown by affected plants: see also the two photographs accompanying this paper.

Study of a species of eelworm closely akin to the eelworm of paper-hanger's paste but differing from it in certain anatomical details has afforded an opportunity for considering the systematic relationships of this interesting worm and its congeners with the result that a new and, to the writer, a more satisfactory grouping is put forward.

In the characters of the head, the structure of the stoma, the shape and build of the oesophagus and the general structure and arrangement of the female gonad as well as in the distribution of the male caudal papillae and the character of the spicules, the genera comprising this group, show obvious resemblances to members of the family Cephalbbidae Chitwood & Chitwood, 1934. The writer therefore proposes their formal inclusion in this family.

Further investigations on the occurrence of Anguillulina dipsaci on onion seed are presented. It is shown by the examination of 2,000 seeds individually that the parasite is usually located on the seed in the region of the hilum. A given seed may have as many as 4·7 worms or only 1 worm attached to it.

A method of seed fumigation with methyl bromide is described whereby the parasites attached to seeds are killed but the seed is unharmed. By the use of a test-bottle technique it has been found that a minimum dosage of 600, i.e. a concentration-time product of 600 involving an exposure to the fumigant of 18 to 24 hours at 24°C. is necessary for the destruction of the parasites attached to the seeds and in such flower-part débris as may be mixed with it.

The fumigant has no harmful effect on the vitality of the seed at dosages sufficient to destroy the parasite nor at much higher dosages. There is thus a wide upper margin of safety in its use. Two practical methods for the fumigation of large quantities of seed are described.

The probable origin of seed-borne infection from lightly infected parent bulbs is discussed. It is shown that at the present time seedborne infection is fairly widespread and has been found to occur on at least 9 different varieties of onion seed as distributed by seed merchants. Recommendations as to control are made which it is suggested would go far to reduce the incidence of the disease in this country.

Schneider (1866), under the name Leptodera curvicaudata, described and figured certain nematodes obtained from moist soil and decaying matter. The species was removed to the genus Rhabditis by Oerley (1886) and the name became R. curvicaudata (Schneider, 1866) Oerley, 1886. Apart from the original description there appears to be no further record of the species in the literature dealing with this genus of free-living nematodes. The discovery of adult worms which agree well with Schneider's account provides an opportunity for redescribing the species and for giving some account of its very interesting association with flies belonging to the genus Psychoda. The writer is indebted for the material to Mr. G. H. Satchell who is investigating sewage purification problems at the University of Leeds (under a grant made by the Department of Scientific and Industrial Research) and discovered the association between the larvae of the worms and Psychoda flies concerning which further particulars are given later on.

The nematodes described and figured in the following pages are specimens mounted in glycerine which were obtained in 1931 (5 males and 4 females) and in 1932 (one female) from pasture soil at Winches Farm, St. Albans. Unfortunately they were not closely examined in the living condition and it is therefore impossible to give any information about their appearance and movements when alive. The nine specimens obtained at the earlier date were passed on to the writer by Dr. D. O. Morgan (who at that time was on the staff of this Institute) and had been found by him whilst examining earthworms in connection with investigations on “gapes” in chickens and young starlings upon which he was engaged at that time, i.e. March, 1931. These worms, after being killed and fixed in weak formalin and processed through dilute glycerine, were finally mounted in glycerine but no detailed study of them was made until recently when, in the course of re-arranging the slide preparations of free-living nematodes, made during the course of several years, they called for identification. The single female worm obtained in April, 1932, was found on a slide along with specimens of Anguillulina agricola, Anguillulina dubia and a female of Teratocephalus terrestris, all of which had been obtained in a Baermann funnel extraction of a piece of turf taken from one of the meadows at Winches Farm.

In a recent paper the writer (Goodey, 1943) has shown that the stem eelworm, Anguilulina dipsaci, occurred in considerable numbers in the scape, i.e. the flower stem, and the inflorescence of onions grown for seed in Sussex during 1943. The worms, mainly consisting of infective larvae, occurred in the dry papery tissues lining the hollow scape, in the pedicels of the flowers and in various of the floral organs, such as withered sepals and petals, in the receptacle and placenta and on the walls of the seed capsule. They were also attached to the outside of the ripened seed. In a second paper (Goodey, 1945) it is further shown that the parasite becomes firmly attached to the seed chiefly in the region of the hilum, whence it cannot be removed by the usual processes of winnowing and cleaning. The foregoing results were obtained from plant material in a dry condition and seed samples which had been threshed and cleaned. Study of this material had made it evident that the parasite must somehow gain access to the living tissues of the scape and inflorescence as these grow from the parent bulb, but it was not apparent how this came about; whether from lightly infected parent bulbs or direct from the soil. Circumstantial evidence had been adduced in the two papers, already mentioned, pointing to lightly infected parent bulbs being the probable source of infection, but the whole matter needed further investigation to elucidate this and other points. In the present communication the results of studies directed to the solution of these questions are given.

Certain species of the nematode genus Anguillulina which commonly occur in close association with the roots of grasses are known to invade the root cortex and to reproduce therein. Thus Anguillulina pratensis, A. obtusa and A. erythrinae all occur in the roots of Agrostis stolonifera L. in pastures at this Institute. The writer has on a few occasions, also found one or two specimens of the small tapering-tailed species, A. agricola and A. costata, within the root cortex of the same kind of grass but further observations are needed before we can say definitely whether these two species actually parasitize roots and reproduce within the tissues. An occasional specimen of A. intermedia has also been found by the writer once or twice inside root tissues but never in what could be regarded as fresh, sound roots, and in view of Linford's (1937) observations on the ability of this species to feed upon fungal hyphae, it is probably safest to regard it as not a true parasite. The examples found may have entered partly decayed roots in search of fungal hyphae.

In a recent paper the writer (Goodey, 1943) dealt with the systematic position of the vinegar eelworm and certain related species. A new subfamily, Turbatricinae, was erected and a new genus, Turbator, proposed for 7 species possessing morphological features differentiating them from the vinegar eelworm, Turbatrix aceti (Müller, 1873) v. aceti Peters, 1927. In regard to this paper, Dr. Gerald Thorne has sent a letter to the writer in which he has been kind enough to draw attention to two points which, in his view, call for emendation and correction, as follows.

Recent re-examination of the paper by Maupas (1900) in which, on pp. 571–575, he describes Aphelenchus agricola de Man, and the figures 2-7 of plate 25 illustrating the same, have confirmed the writer in a view he expressed in an earlier paper (Goodey, 1928, p. 135) that Maupas was correct in identifying: the worms found by him in Algiers with Aphelenchus agricola de Man, 1881 = Aphelenchus avenae Bastian, 1805.

Disease in onions due to the stem eelworm, Anguillulina dipsaci, causing a soft rot of the bulb and a general stunting of the plant, commonly called “bloat,” has been known for many years. Its symptoms and pathology were fairly fully described and figured by Bos (1888–92). More recently a considerable amount of investigation on the disease has been carried out in U.S.A., particularly by Newhall and Chitwood [see Newhall & Chitwood (1940), Chitwood, Newhall & Clement (1940), Newhall (1941) and (1943)]. It is not intended to discuss this work here but merely to indicate that our knowledge of the disease set up both in the seedling plant and in the grown bulb is now fairly full and detailed.

Certain gaps in out knowledge of the bionomics of the disease have, however, remained, particularly those relating to its sporadic incidence in areas where onions have' not previously been grown or have not been grown for many years. One possibility which needed exploration was whether the parasite could be seed-borne. Bos (1889, ṕ. 346) provided a note on this matter. He said that in seed harvested from a diseased crop of onions and sent to him in the spring of 1886, he was able on close examination to see that some of the seed contained eelworms but only in small quantity.

Heterodera cruciferae n. sp., parasitic upon Brassicas and other Cruciferous plants, is described and compared with H. schachtii, the sugar beet eelworm.

The new species differs from the sugar beet eelworm in its host range, in the reaction of the larvae to root excretions of sugar beet and in the time of hatching of the larvae. The cysts are somewhat shorter and rounder than in the sugar beet eelworm and differ in having attached to the vulva a mass of jelly-like substance containing eggs and sometimes one or two males. The larvae are shorter than in H. schachtii. The males are similar but tend to be smaller and with shorter stylets.

The results of infection experiments with cysts from the roots of dock and of clovers indicate that these cysts are of the same race, and are probably a biological strain of the sugar beet eelworm H. schachtii.

The identification of the species of the genus Trichuris has been much simplified since the appearance of a paper by Chandler in 1930 in which he pointed out that the prepuce-like expansion surrounding the extruded spicule has very little diagnostic value because of its extreme variability. The length and appearance of the spicule is useful only when used in conjunction with other characters for this is a variable structure. However, the six species with which he was concerned could readily be distinguished by certain internal structures which seem to exhibit great constancy and reliability. These structures are the length of the cloacal tube and its diverticulum for the head of the spicule, the length and shape of the ejaculatory duct and the nature of the folding of the vas dcferens and of the testis. Using these characters and other minor ones, he was able to give useful descriptions of the males of Trichuris trichiura, T. vulpis, T. ovis, T. minuta and T. leporis and to describe a new species T. tenuis.

Eelworm disease of tulips was first reported by Bos (1906) in bulbs of the varieties “La Reine” and “Yellow Prince,” grown at Sassenheim in Holland. Westerdijk (1906) dealt a little more fully with the same outbreak, described the typical brown ring symptoms shown by the bulbs and reported on a few preliminary trials designed to determine whether the parasite belonged to the same biological race as that attacking hyacinths.

Theobald (1912) reported the presence of Tylenchus devastatrix in a number of tulip bulbs (variety unnamed) which had been spnt to him from Dublin, Ireland. In a later note Theobald (1924–25) speaks of a tulip grower in Thanet, Kent, having such bad attacks of eelworm in his bulbs that he decided to remove his nursery to clean ground. Whether the stem eelworm was actually found in affected tulip bulbs was, however, not stated.

The material described consists of two small collections. One composed mainly of helminths from birds, was collected by Major T. A. Cockburn, M.D., D.P.H., on the Gold Coast in 1943. The other was collected from mammals by Dr. K. Morris, of the medical department, Kumasi, in 1939. To both of these collectors and to Dr. R. T. Leiper, C.M.G., F.R.S., who kindly put the material at my disposal, I am much indebted.

The bird material contained 8 different genera, of which one is a tremtftode, three are cestodes and the others are nematodes. The Acanthocephala are not represented.

A Squacco Heron, Ardeola ralloides, yielded a number of specimens of the trematode Clinostomum complanatum (Rud., 1814), Braun, 1899. They were taken from the oesophagus where they were actively moving about at the post-mortem examination. It is a small worm between 3 and 4 mm. long, strongly muscular with comparatively large suckers. The vitellaria are abundant and so deeply staining as somewhat to obscure the other organs. It has previously been recorded as a parasite of Ardea cinerea and Nycticorax griseus in Europe, but apparently both this host and this geographical distribution are new records. The vector is a fish; Ciurea in 1911 having implicated Perca fluviatilis.

On 23/3/43 a small experiment was sown with commercial onion seed at Kirton, being one of a series laid down at county oentres in order to study the effect of different times of lifting on the development of wastage in store. Four varieties, which may be designated A, B, R, U, were sown in strips of three rows 10in. apart, in triplicate, the rows being 41 yards long and forming three randomised blocks. The liftings were also in randomised block pattern, 3 × 3, across the length of the rows. Two sub-plots of each variety were taken for convenience, consisting of adjacent six-foot lengths across the three rows, the produce of each sub-plot being put into a separate box immediately on lifting.