bluuebunny/crossref_metadata_2025 huggingface dataset:
Theoretical morphology of echinoid growth
Authors: Raup David M.
Published: June 2019

Deutler's classic work (1926) provides the basis for an analysis of plate growth in echinoids. Deutler showed that the concentric growth rings found within each plate may be used to reconstruct the ontogeny of the entire plate pattern.

New observations of growth-line configurations, particularly inStrongylocentrotus pallidus(Sars), have been used to derive a general model for echinoid growth. The plate mosaic is assumed to be the result of close packing of the growing plates. The shape of a given plate thus depends on its size and position relative to surrounding plates.

The rate of meridional growth of a plate can be shown to change regularly with increasing distance from the echinoid's apical system. Migration of plates away from the apical system thus causes change in the rate of plate growth. The rate of plate migration is strongly influenced, in turn, by the rate of supply of new plates at the apical system.

A mathematical model has been developed from these considerations which, when treated by digital computer (with x-y plotter output), produces ideal plate patterns (including growth rings). The constants in the model may be varied to produce a broad spectrum of echinoid plate patterns.
Ontogeny and the explanation of form: an allometric analysis
Authors: Gould Stephen Jay
Published: June 2019

Significant allometry occurs during the ontogeny of every variable in Poecilozonites bermudensis, a Pleistocene-Recent land snail from Bermuda. The adaptive significance of shell allometry may lie in the necessity for preserving a high value of the foot surface/body volume ratio. In the absence of allometry, this ratio must decline as size increases. Three strategies could be used to keep this ratio sufficiently high: positive allometry of foot growth, structural strengthening of the foot, and the development of a foot initially large enough to withstand decline in the ratio during growth. As indicated by ontogenetic changes in apertural shape, a small amount of positive allometry occurs during ontogeny of the foot in P. bermudensis. This is not sufficient to prevent decline of the foot surface/body weight ratio, and I conclude that the strategy of possessing an initially large foot is also used. A simple model of doming, reflecting this latter strategy, is constructed (doming is a major allometric feature of P. bermudensis). In this model, the foot volume/body volume ratio is constant throughout ontogeny in each of two shells, but this value is higher in the more strongly domed shell.

Knowledge of ontogenetic allometry is a prerequisite for understanding the phylogeny of P. bermudensis, for paedomorphosis has been the primary evolutionary event in this taxon. Paedomorphic samples are scaled-up replicas of juvenile shells of the central stock, P. bermudensis zonatus. The degree of ontogenetic retardation in development is the same for all variables (color, thickness, and external shape). Paedomorphosis has occurred several times during the Pleistocene, providing an example of iterative evolution at the infraspecific level. Four paedomorphic taxa are known: P. b. fasolti, P. b. siegmundi, P. b. sieglindae, all new; and P. b. bermudensis (Pfeiffer). They have the geographic distribution (small, peripheral isolates) expected of diverging populations and seem to be genetically distinct entities, not mere phenotypic variants. The most paedomorphic subspecies originated in red soils; paedomorphs did not evolve in times of carbonate-dune deposition. The thin shells of paedomorphs might have been adaptive in the low-calcium environment of red soils. The general significance of iterative evolution at the infraspecific level does not provide an adequate model for corresponding events at higher levels.
Ontogeny of the crinoid Eucalyptocrinites
Authors: Macurda Donald B.
Published: June 2019

The calyx of a Paleozoic camerate crinoid is composed of a mosaic of large, polygonal plates. Ontogenetic size increase results from accretionary additions of calcite to thecal plates. When new calcite is added to the lateral edge of a plate, a new layer is also added over the external surface, obscuring the earlier growth stages of the plate. However, ontogenetic development can be studied by measurement of a growth series. This is illustrated by regression analysis of growth series of two Silurian species of the genus Eucalyptocrinites: E. crassus (Hall) and E. tuberculatus (Miller & Dyer). Growth of the principal plates is isometric; most growth parameters have a very similar mode of development in both species; only a few parameters show any specific difference. A table of correlation coefficients for 51 growth parameters demonstrates that the entire development of the calyx was highly coordinated throughout life, with coefficients almost always equal to or larger than 0.90. Integrated expansion of the cup plates provided a larger cavity for the viscera. The stem increased in diameter to support the increasingly larger theca, as did the diameter of the root system. Growth of the vaulted plates in the upper part of the theca provided a protective recess for the arms, which probably contributed to the evolutionary success of this animal on a widespread basis during the Silurian and Devonian.

Based upon growth studies, the following synonymies are suggested: E. constrictus Hall, E. ellipticus Miller, E. ovalis Hall, and E. subglobosus Miller are synonyms of E. crassus; E. clrodi Miller is a synonym of E. tuberculatus Miller & Dyer.
Aegyptianella pullorumCarpano 1928—fine structure and taxonomy
Authors: Bird R. G. , Garnham P. C. C.
Published: June 2019

Intraerythrocytic granules in the blood of Sudanese fowls first seen by Balfour (1908) were namedAegyptianella pullorumby Carpano (1928).

Electron microscopy of a Rhodesian strain ofA. pullorumindicated the similarity between these organisms and theRickettsia-PLT group of organisms, also their dissimilarity to Sporozoa which we have studied. The organism was coccoid or coccobacillary, measuring up to 0·6 μm in diameter, and in longitudinal sections 1·5–3 μm. Pleomorphic and dividing forms were observed. Each organism was surrounded by two unit membranes with short internal invaginations from the inner membrane only. A layer of ribosome-like particles varying in density and depth gave the impression of an outer cortex. Irregular extensions of this layer towards the centre of the organism followed the lines of fine DNA-like filaments forming a web lattice throughout the substance of the organism. There was no well-defined nucleus as seen in Protozoa. Single as well as groups of organisms were situated in vacuoles lined by a membrane similar to the erythrocytes' own outer membrane. No intranuclear organisms were seen.

The similarity of these organisms to symbionts studied by Roshdy and Bird in both adult and immature stages ofA. persicusis illustrated. From this evidence, and its apparent likeness to the tick-borne fever agent, there is good reason for includingA. pullorumamong the Rickettsiaceae. The position suggested for it is between theRickettsiaand PLT group of organisms, closely allied toWolbachia, the agent of tick-borne fever (Cytoecetessp.) and the agent of bovine heart water disease (Cowdria ruminantium).

We thank Mr R. Jacobson, F.I.M.L.T. for his willing assistance in conducting the sensitivity test, also Miss L. Lanigan and Mr D. Day for their technical and photographic assistance.
Life-cycles of helminth parasites usingGammarus lacustrisas an intermediate host in a Canadian lake
Authors: Denny M.
Published: June 2019

The systematics and life-cycles of the helminths of a local population ofGammarus lacustrisin a eutrophic lake near Edmonton, Alberta, is reported as part of a larger study of the composition and seasonal dynamics of the helminth fauna of gammarids.

A total of 12 species of helminths, including eight cestodes, one nematode and three acanthocephalans, were recovered. Of these, eleven were new host records, ten were assigned to an intermediate host species for the first time, and one,Hymenolepis albertensissp.nov., was described for the first time.

Adults of all twelve helminths were raised in experimentally infested birds and the life-cycles of five species (Lateriporus clerci, L. skrjabini, Hymenolepis albertensissp.nov.,Fimbriaria fasciolarisandPolymorphus marilis) were completed in the laboratory. The larvae are described, and the developmental period in the gammarids, prepatent period and life span of the adults are given for many of the helminths.

The rate of development of the cysticercoids ofLateriporus skrjabiniwas shown to be directly related to the size of the gammarid and inversely related to the intensity of infestation.

The proboscis-hook formula was not a good diagnostic character for the separation of the three acanthocephalans,Polymorphus contortus, P. marilisandP. paradoxus;however, the size of the largest hook and the structure of the cystacanth body-wall were good diagnostic characters.

I am indebted to Dr J. C. Holmes for advice and encouragement at all stages of the study. I also wish to thank Drs S. Prudhoe and D. R. R. Burt for their editorial assistance, Mr L. Graham for many helpful suggestions and information on the natural definitive hosts of the species encountered, Mr R. Podesta for his laboratory assistance, and Miss E. D. Senio for caring for the ducklings during their first few days of life. The study was supported by the Francis F. Reeve Foundation Graduate Bursary, the Queen Elizabeth Education Scholarship Fund, by the Department of Zoology through a Teaching Assistantship, by a grant from the R. B. Miller Biological Station Fund and by an N.R.C. operating grant (A–1464) to Dr J. C. Holmes.
The morphology and biology of Trypanosoma (Herpetosoma) evotomys of the bank-vole, Clethrionomys glareolus
Authors: Molyneux David H.
Published: June 2019

The morphology and biology of the various stages of the life-cycle of Trypanosoma evotomys has been studied in laboratory bred vertebrate and invertebrate hosts. The morphology of T. evotomys in the blood of the bank-vole, Clethrionomys glareolus, is typical of that of a trypanosome of the subgenus Herpetosoma, but the shape and size of the trypanosome in C. glareolus is more variable during the reproductive phase of the infection than in the adult phase. The duration of the infection of T. evotomys in C. glareolus varies from 22 to 31 days in experimental infections and the incubation period of the infection initiated by metatrypanosomes is 5–6 days. The peak of the parasitaemia varied from 15000 to 55000 parasites per mm3 of blood. The reproductive stages of T. evotomys are found in the spleen and lymphoid tissue (appendix) of the bank-vole, and reproduction is by equal, binary or multiple fission in the amastigote stage. T. evotomys was not transmissible to M. agrestis, mice or rats. Cyclical development of T. evotomys took place in the flea, Nosopsyllus fasciatus, and metatrypanosomes developed in the intestine of the flea. No intracellular forms of T. evotomys were found in the mid-gut of the flea.

The encouragement, help and advice of Dr P. Tate is gratefully acknowledged. Financial support was received from the Agricultural Research Council to whom thanks are also due.
The effect of physical factors on the rate of respiration of the infective larvae of Strongyloides ratti Sandground, 1925
Authors: Barrett J.
Published: June 2019

Dense larval suspensions have a higher Qo2 than dilute ones, probably due to an oxygen debt acquired during preliminary washings. Ammonia (0·1M) did not affect the respiratory rate of the infective larvae of S. ratti. Mechanical agitation of larvae reduced their rate of respiration.

The partial pressure: respiration curve of the infective larvae was sigmoidal, that of larval homogenates was a rectangular hyperbola. At low partial pressures of oxygen the respiratory rate depends to a certain extent on the rate of change of the partial pressure.

In 100% oxygen the respiratory rate of the larvae is at first stimulated and then falls to its initial level. On returning to air after 100% oxygen, the respiratory rate is at first depressed and then recovers.

The infective larvae of S. ratti develop an oxygen debt when kept under anaerobic conditions. During the recovery period, which lasts for about 1 h, the Qo2 may increase by up to 100%.

The respiration of the infective larvae increases as the temperature is increased. When larvae are maintained at 37 °C there is a gradual decrease in their rate of respiration and this change is apparently irreversible.

The rate of respiration of the larvae is slightly inhibited at low pH values and slightly stimulated at high pH values.

Moderate levels of carbon dioxide (5%) have no effect on the respiratory rate of the infective larvae of S. ratti, high levels of carbon dioxide (10–20%), have a definite narcotic effect on the larvae.

The respiration of the infective larvae is unaffected by osmotic pressures up to an equivalent of 1% sodium chloride. Above this level the respiratory rate is at first stimulated then decreases.

This work was carried out during the tenure of a Medical Research Council Scholarship.
The structure and development of Histomonas meleagridis (Mastigamoebidae: Protozoa) in the female reproductive tract of its intermediate host, Heterakis gallinarum (Nematoda)
Authors: Lee D. L.
Published: June 2019

The ultrastrcuture and development of the protozoan Histomonas meleagridis in the reproductive system of the female nematode, Heterakis gallinarum, have been described. It has been shown that there is a distinct cycle of events in the reproductive system. The stage of Histomonas in the germinal zone of the ovary is extracellular; the protozoan feeds and multiplies here. The histomonads move down the ovary with the oogonia and become intracellular when they penetrate the developing oocytes in the growth zone of the ovary. This is apparently an active penetration of the oocyte by the parasite. Feeding and division of the histomonad occurs in the oocyte and also in the newly formed egg; apparently a gradual reduction in size occurs along the reproductive system. These stages in the parasite are similar to the tissue-inhabiting stages in the bird but are much smaller. There are no mitochondria present.

There is strong circumstantial evidence that the nematode is able to repair damage to the wall of the reproductive system and to the oolemma caused by the protozoan.

I wish to thank Dr E. E. Lund of Beltsville Parasitological Laboratory, Maryland, U.S.A., who very kindly sent me some of his Histomonas-free strain of Heterakis and Dr L. P. Joyner and Mr C. C. Norton of the Central Veterinary Laboratory, Weybridge, for the strain of Heterakis which was found to transmit Histomonas wenrichii. I also wish to thank Mrs B. Fisher, Mr B. Millard and Mr M. Shirley for technical assistance and Mr P. Rogers for assistance with the photography.
Skin penetration by cercariae of the bird schistosomeAustrobilharzia terrigalensis:the stimulatory effect of cholesterol
Authors: Clegg J. A.
Published: June 2019

An artificial skin of hardened gelatine was used to examine the factors affecting penetration of skin by cercariae of the bird schistosome,Austrobilharzia terrigalensis.

The percentage of cercariae able to penetrate through a gelatine membrane was increased by a factor of 3–4 by coating the membrane with a thin layer of lipid collected from the surface of chicken skin.

The free sterol fraction, isolated from chicken skin surface lipid by thin-layer chromatography, stimulated penetration to the same extent as whole skin lipid.

Cholesterol was detected in the sterol fraction by mass spectrometry and pure cholesterol had the full stimulating effect on cercarial penetration.

Skin lipid, from which free sterols had been removed, lost the stimulatory effect on cercariae, but full activity was recovered by adding cholesterol to the sterol-free lipid. Fractions of skin lipid containing free fatty acids or triglycerides, wax esters and sterol esters similarly failed to stimulate penetration.

These results establish that penetration ofA. terrigalensiscercariae is greatly stimulated by the free sterols present in the surface lipid of chicken skin but cholesterol may not be the only active sterol. Cholestanol and the plant sterols campesterol and β-sitosterol were also detected in chicken skin surface lipid. These sterols were not tested for activity on cercariae because samples free from cholesterol could not be obtained.

Some cercariae were able to penetrate plain gelatine membranes not coated with cholesterol but small amounts of free sterol were detected in the gelatine itself. This sterol could not be completely removed by prolonged solvent extraction and consequently it is not known whether any cercariae are able to penetrate in the complete absence of sterols.

Temperature had a marked effect on penetration of cercariae; lowering the temperature from 40 to 25 °C reduced the number of successful penetrants by a factor of 4.

I am grateful to Miss V. Bowen for excellent technical assistance and to Dr J. McLeod of the Research School of Chemistry, Australian National University, who performed and interpreted the mass spectrometry. This investigation was partly supported by a research grant from the World Health Organization.
The blood picture resulting from Nuttallia (= Babesia) rodhaini and Nuttallia (= Babesia) microti infections in rats and mice
Authors: Nowell Frank
Published: June 2019

The parasitaemia and associated blood picture following infections of Nuttallia rodhaini in rats and mice, and N. microti in rats are described. After inoculation of the blood stages of these parasites, it is evident that only further blood stages occur in the host animal. Infections with both piroplasms follow a similar course, there being a prepatent period followed by a patent infection which reaches a peak and then disappears. The prepatent period is an artifact due to the rarity of the parasites in the peripheral blood. The patent infection of N. rodhaini in rats and mice rapidly reaches a peak of up to 90% R.B.C. infected. That of N. microti develops more slowly and rarely reaches 20%. Rats show age resistance to both piroplasmoses but none is shown by mice aged up to 1 year against N. rodhaini infection. Increase of the parasite inoculum dose decreases the prepatent period and also the time from infection to the peak. In rats there is a corresponding increase of the peak but in mice this remains constant. N. microti infections in rats are enhanced by splenectomy, the peak being higher but the time from infection to the peak not altering. The parasitaemia produced by both piroplasms results in a temporary anaemia and reticulocytosis. The anaemia is not prolonged which does not suggest autoimmune reactions. Both piroplasms preferentially invade reticulocytes as compared with mature erythrocytes although this is apparently reversed at the onset of reticulocytosis.

An explanation of the mechanism of the parasitaemia of the piroplasms in rats and mice is suggested.

This paper is a report of work carried out in part for a thesis submitted for the degree of Ph.D. in the University of London. The work was aided by an S.R.C. research studentship. I would like to thank Dr F. E. G. Cox for his supervision and also for performing the splenectomies.
L'œuvre de la Croix-Rouge en Pologne
Authors: Dománska I.
Published: June 2019

L'année 1969 marque le cinquantième anniversaire de la fondation de la Croix-Rouge polonaise.

Dans notre pays, l'assistance qu'apportent la population et les associations bénévoles aux soldats blessés est née d'une tradition très ancienne et très belle; elle remonte aux temps de l'insurrection de Kosciuszko, et elle s'est poursuivie lors des insurrections nationales de 1830 et 1863. Durant les 120 années, et plus, de servitude et de démembrements que connut la Pologne, elle s'est étendue à ceux qui étaient emprisonnés parce qu'ils luttaient pour la liberté et la justice sociale. L'une des organisations d'assistance bénévole et de premiers secours fut appelée Société de la Croix-Rouge (1862–1886).
Après la XIVe Conférence Internationale de l'Action Sociale
Authors: Esnard M.
Published: June 2019

Selon certains auteurs, les congrès seraient actuellement l'antidote de l'isolement de l'homme moderne. Faut-il voir là la raison pour laquelle, alors que séminaires et rencontres se multiplient, la Conférence Internationale de l'action Sociale connaît toujours une participation importante?
Dissipation and Phytotoxicity of Dicamba
Authors: Hahn R. R. , Burnside O. C. , Lavy T. L.
Published: June 2019

Dissipation of 2-methoxy-3,6-dichlorobenzoic acid (dicamba) was greater in Sharpsburg silty clay loam soil than in Anselmo sandy loam soil and was faster in the topsoil than in the subsoil. Breakdown increased with increasing soil incubation temperatures. Phytotoxicity of dicamba and 3-amino-2,5-dichlorobenzoic acid (amiben) in aqueous solutions decreased upon exposure to sunlight. Amiben was more susceptible to photodecomposition than was dicamba. Aqueous dicamba solutions exposed to sunlight for 16 days decreased growth of cucumber (Cucumis sativus L.) seedlings, while amiben solutions caused no growth reduction after 2 days' sunlight exposure. Dicamba solutions exposed to 60 C showed increased phytotoxicity while amiben solutions were unaffected. Dicamba was most phytotoxic to corn (Zea mays L.) seedlings at pH 4 and to cucumber seedlings at pH 5. Dicamba solutions were taken up by both shoots and roots of corn and cucumber seedlings; however, root uptake resulted in greater growth reductions.
The Response of Kentucky Bluegrass to Soil Residues of Preemergence Herbicides
Authors: Smith G. S. , Callahan L. M.
Published: June 2019

Common Kentucky bluegrass (Poa pratensis L.) sod-plugs were grown in the greenhouse in soil freshly treated with 11 herbicides and in soil collected from the 0 to 2 and 2 to 4-inch depths of field plots treated 10 months earlier with the same herbicides. Fresh herbicide treatments reduced significantly the root regrowth of the bluegrass plants. The 12-lb/A rate of the fresh application of 1-(2-methylcyclohexyl)-3-phenylurea (siduron) caused the least chemical inhibition of root regrowth. The most phytotoxic fresh applications were 2-chloro-4-ethylamino-6-isopropylamino-s-triazine (atrazine) and 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine), both killing the bluegrass plants at the 4 lb /A rate. Root regrowth of bluegrass grown in the herbicide residue samples was significantly reduced for all treatments. Herbicides which tended to persist in the 0 to 2-inch soil level and were most phytotoxic to root regrowth were simazine, polychlorodicyclopentadiene isomers (hereinafter referred to as bandane), N-(2-mercaptoethyl)-benzenesulfonamide S-(O,O-diisopropyl phosphorodithioate) (bensulide), and 2,6-di-tert-butyl-p-tolyl-methylcarbamate (terbutol). Those herbicides which tended to leach into the 2 to 4-inch soil level and cause the greatest reduction of root regrowth were N-butyl-N-ethyl-alpha, alpha, alpha-trifluoro-2,6-dinitro-p-toluidine (benefin), α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin), atrazine, and O-(2,4-dichlorophenyl) O-methyl isopropylphosphoramidothioate (DMPA). Herbicides which tended to leach uniformly throughout the 0 to 2 and 2 to 4-inch soil layers were siduron, an equal mixture of 1,1-dimethyl-4,6-diisopropyl-5-indanyl ethyl ketone and 1,1-dimethyl-4,6-diisopropyl-7-indanyl ethyl ketone (hereinafter referred to as sin-done), and dimethyl 2,3,5,6-tetra-chloroterephthalate (DCPA).
Inactivation of Herbicides by Activated Carbon and other Adsorbents
Authors: Coffey David L. , Warren G. F.
Published: June 2019

A root bioassay was used to compare the adsorption of herbicides by activated carbon with that of muck soil, bentonite clay, a cation exchange resin, and an anion exchange resin. The effectiveness of different adsorbents was determined by comparing the concentrations of herbicide required to give 50% root inhibition of the test plant. Of eight herbicides tested, six were more strongly adsorbed by activated carbon than by any of the other adsorbents. The relative amount of adsorption by activated carbon as measured by the reduction in biological activity was as follows: isopropyl N-(3-chlorophenyl)-carbamate (CIPC) > α,α,α,trifluro-2,6-dinitro-N, N-dipropyl-p-toluidine (trifluralin) > 2,4-dichlorophenoxyacetic acid (2,4-D) > N,N-dimethyl-2,2-diphenylacetamide (diphenamid) > dimethyl 2,3,5,6-tetrachloroterephthalate (DCPA) > 4,6-dinitro-o-sec-butylphenol (DNBP) > 3-amino-2,5-dichlorobenzoic acid (amiben). The biological activity of 1,1'-dimethyl-4,4'-bipyridinium salt (paraquat), a cationic herbicide, was not reduced by activated carbon, but was reduced by bentonite clay and the cation exchange resin. DNBP was more strongly adsorbed by the anion exchange resin than by activated carbon. Desorption from activated carbon varied greatly for the herbicides tested. The most readily desorbed herbicide was 2,4-D while CIPC and DNBP showed little or no desorption.
Population Dynamics of Downy Brome
Authors: Young James A. , Evans Raymond A. , Eckert Richard E.
Published: June 2019

We investigated the periodicity of germination, longevity of caryopses viability, and reproductive capacity of downy brome (Bromus tectorumL.) populations in relation to chemical and mechanical fallow and fall tillage weed control treatments. The important factors in the dynamics of downy brome populations are: (a) large numbers of viable caryopses are carried from 1 year to the next in the litter and soil; (b) downy brome caryopsis production is density dependent; and (c) the simultaneous germination characteristics of freshly harvested downy brome caryopses can be conditioned environmentally to continuous germination.
Effects of Organic Arsenical Herbicides on Cotton Response and Chemical Residues
Authors: Baker R. S. , Arle H. F. , Miller J. H. , Holstun J. T.
Published: June 2019

The influence of timing and method of application of sodium or disodium salts of methanearsonic acid (MAA) on cotton (Gossypium hirsutum L.) response, arsenic content of seed, and arsenic content of soils, was studied in field experiments in California, Arizona, and Mississippi. Methods of application consisted of directed and topical sprays. Directed sprays were applied to cover the small weeds in the drill row with a minimum of contact on cotton leaves more than 2 to 3 inches above the ground. Topical sprays were applied from nozzles positioned over the cotton in such a way that the entire cotton plant was subject to coverage. Rates of application were either 2 or 3 lb/A of the salts, and either two or three applications were made to treated plots. Cotton appeared highly tolerant to directed applications. A topical application to cotton 2 to 4 inches slightly reduced yields, but topical applications made at later stages of growth caused progressively severe reductions in yields and delayed maturity. The arsenic content of cottonseed from treated plots was not significantly higher than in that from untreated checks providing that applications were restricted to prebloom stages. Either directed or topical applications made during the blooming stage resulted in detectable increases of arsenic in the cottonseed. The effect of the treatments on arsenic content of soils was relatively small in comparison with natural levels, but the effect was detectable at one of the three locations.
Microbial Degradation of Five Substituted Urea Herbicides
Authors: Murray Don S. , Rieck Walter L. , Lynd J. Q.
Published: June 2019

Phytotoxicity of five substituted urea herbicides 3-(3,4-dichlorophenyl)-1,1-dimethylurea (diuron), 3-(p-chlorophenyl)-1,1-dimethylurea (monuron), 3-phenyl-1,1-dimethylurea (fenuron), 3-hexahydro-4,7-methanoindan-5-yl) −1,1-dimethylurea (norea), and 3-(m-trifluoromethylphenyl)-1,1-dimethylurea (fluometuron) at 0, 10, 100, and 1000 ppm were determined in factorial combination at four urea nitrogen levels of 0, 45, 450, and 900 ppm with three Aspergilli: A. niger, A. sydowi, and A. tamarii. Response interactions were apparent, with all three fungi most tolerant for fenuron and least for diuron. Apparent tolerance order of the three intermediates were: A. niger, norea > fluometuron > monuron; A. sydowi, fluometuron > monuron > norea; and A. tamarii, fluometuron > norea > monuron. Oat (Avena sativa L.) bioassay for residual herbicide toxicity indicated significant differences in herbicide degradation rates between these three fungi at 5, 10, and 20 ppm in Eufaula sand. Diuron was more rapidly degraded than monuron at these levels with fluometuron and norea somewhat intermediate. A. niger was most effective in degradation of these herbicides with A. tamarii greater than A. sydowi. High nitrogen levels in soil organic matter amendment generally favored increased rates of urea herbicide degradation.
Influence of Simazine on Apparent Photosynthesis of Aquatic Plants and Herbicide Residue Removal from Water
Authors: Sutton David L. , Durham D. A. , Bingham S. W. , Foy C. L.
Published: June 2019

Simazine (2-chloro-4,6-bis(ethylamino)-s-triazine) at 0.12 to 1.0 ppmw in nutrient cultures of common duckweed (Lemna minor L.), elodea (Elodea canadensis Michx.), and parrotfeather (Myriophyllum brasiliense Camb.) inhibited oxygen evolution within 24 hr. Of the plants studied, the submersed form of parrotfeather exhibited the greatest reduction in apparent photosynthesis as measured by dissolved oxygen in the water. Simazine in nutrient culture without plants remained relatively stable during the treatment period; a slight, but not significant, diminution of chemical was detected after 4 days. Each species, elodea or emersed parrotfeather, reduced the concentration of simazine in solution within 48 hr after treatment.
Effects of Age, Burial, and Region on Germination and Viability of Halogeton Seed
Authors: Robocker W. C. , Williams M. C. , Evans R. A. , Torell P. J.
Published: June 2019

The longevity of brown and black forms of seed of halogeton (Halogeton glomeratus (M. Bieb.) C. A. Mey.), buried at four depths, was determined for a 10-year period in Nevada, Idaho, Utah, and Washington. The black form of seed had almost 100% field germination at all depths by the end of the first year and had completely germinated or was nonviable by the end of the second. Brown seed on the soil surface began field germination the first year at all locations and had germinated or become nonviable at the end of 6 years. Burial at 1, 3, and 6 inches delayed the peak of viability and tended to increase longevity of brown seed. Germination was less than 0.5% at the end of 10 years, and viability was near zero under both field and laboratory conditions. Seed germinated and lost viability most rapidly in Washington, the location where most favorable winter conditions for germination occurred.
Seedling Development and Bud Ontogeny in Western Ironweed
Authors: Scifres C. J. , McCarty M. K.
Published: June 2019

Western ironweed (Vernonia baldwini Torr.) seedlings emerge from an exalbuminous achene. By 6 days after germination, a cortical collar was discernible between the hypocotyl and root. A pair of lateral buds arose exogenously from the outer two to three layers of this zone through dedifferentiation of cortical parenchyma. Sprouting of lateral buds could be stimulated in a few seedlings by 15 days after germination if they were clipped between the cotyledons and the hypocotyl-root transition zone. One of the seedling buds could be activated by top removal up to 40 days after germination when both could be stimulated to sprout. Ability to form new stems vegetatively was reflected in rate of anatomical maturity of the seedling buds.
Influence of Time and Method of Application on Turkey Oak Response to Picloram + 2,4-D
Authors: Coble H. D. , Upchurch R. P. , Keaton J. A.
Published: June 2019

Naturally-established turkey oak (Quercus laevis Walt.) shoots were treated with aqueous solutions of the product picloram + 2,4-D (4-amino-3,5,6-trichloropicolinic acid + 2,4-dichlorophenoxyacetic acid) and with picloram pellets. Various application methods were utilized at several dates during the year. Responses measured 14 and 17 months after initial treatments were percent control of original shoots, percent regrowth, plant height, and live stems/plant. Leaf-stem-basal treatments provided the highest degree of control of any method studied, averaging 87% total shoot control over five treatments dates. Foliar, mist-blower, and leaf-stem applications showed no differences, averaging 75%, 79%, and 78% control, respectively. Basal applications gave poorest results averaging only 12% control over five dates. No differences were observed among treatment dates for applications made during the growing season after the full-leaf stage, but treatments made before full-leaf provided less control than others. Soil applications of picloram pellets were more effective when applied during the early spring and summer than during fall or winter but were less effective than treatments applied to foliage at all dates.
Growth Characteristics and Herbicide Susceptibility of Texas Panicum
Authors: Chandler James M. , Santelmann P. W.
Published: June 2019

Texas panicum (Panicum texanum Buckl.) seed were collected and treatments applied in an effort to increase germination. Also, plants were grown in the field and growth characteristics studied. Poor seed germination was obtained with all treatments, but wide variation in storage temperature produced the best germination. Seedlings emerged from seed planted as deep as 3 inches. An average of 118 heads per plant and 195 seed per head were produced, or 23,010 seeds per plant. Plant, seed head, and seed development followed sigmoid growth patterns. The species was resistant to most preplant and preemergence herbicides used in screening experiments.
Rainfall Effects Following Herbicidal Treatment of Woody Plants
Authors: Upchurch R. P. , Coble H. D. , Keaton J. A.
Published: June 2019

In North Carolina, the shoots of naturally-established, field grown, foliated specimens of turkey oak (Quercus laevis Walt.) and red maple (Acer rubrum L.) were treated in August with aqueous dilutions of three herbicidal products at three rates each. Simulated rainfall was applied at ½ or 1 inch at 5, 15, 60, or 120 min after herbicidal application. Responses measured 10 and 13 months after herbicidal application were percent control of original shoots, percent control of new shoots, shoot height, and number of live stems/plant. Neither the ester nor amine derivatives of 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) were reduced as to their action on woody plants by the simulated rainfall applied. The action on woody plants of 4-amino-3,5,6-trichloropicolinic acid (picloram) plus 2,4-dichlorophenoxyacetic acid (2,4-D) was markedly reduced by the application of all of the simulated rain treatments at any of the intervals at which they were applied following herbicidal treatment.
Selective Control of Hoary Alyssum in Alfalfa
Authors: Kust Cyril A.
Published: June 2019

Hoary alyssum (Berteroa incana (L.) D.C.) was selectively controlled in alfalfa (Medicago sativa L.) by 2-chloro-4,6-bis(ethylamino)-s-triazine (simazine) at 2 lb/A, 3-tert-butyl-5-bromo-6-methyluracil (hereinafter referred to as DuPont 733) at ½ and 1 lb/A, 2,4-dichlorophenoxybutyric acid (2,4-DB) at ½ and 1 lb/A, and by 3-tert-butyl-5-chloro-6-methyluracil (terbacil) at ½ and 1 lb/A. Alfalfa yields were not reduced with consecutive applications for 3 years with the exception that simazine at 2 lb/A caused a significant reduction in first harvest hay yields in the first 2 years. Herbicide applications were made as soon as possible after the last forage harvest in early fall. Treatment at that time destroys the existing photosynthetic area and should reduce the accumulation of carbohydrate reserves in the roots, thereby inhibiting the development of cold hardiness by hoary alyssum plants.
Placement of EPTC-Fertilizer when Seeding Birdsfoot Trefoil
Authors: Linscott D. L. , Hagin R. D.
Published: June 2019

While establishing birdsfoot trefoil (Lotus corniculatus L., var. Viking), the following weed control treatments were compared for effectiveness: (A) ethyl N,N-dipropylthiocarbamate (EPTC) impregnated on granular fertilizer and applied through the placement assembly of a grain drill during planting; (B) EPTC applied as a spray before planting and incorporated by multiple disking; (C) a combination of treatments A and B. All treatments involving EPTC controlled annual grasses. Where perennial grasses and sedges were abundant, treatment C was more effective than the others. All three methods resulted satisfactory birdsfoot trefoil establishment.
The Disappearance of Trifluralin from Field Soils
Authors: Parka S. J. , Tepe J. B.
Published: June 2019

Soil samples were collected from 107 locations following the commercial application of α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) for 1, 2, 3, or 4 consecutive years. Analyses of soil samples indicated that trifluralin does not accumulate with repeated annual application and that a steady and continuous decline in the level of trifluralin present in the soil occurred with time.
Effect of Prometryne on14CO2Fixation in Cotton and Soybean
Authors: Sikka H. C. , Davis D. E.
Published: June 2019

Photosynthetic14CP2fixation was significantly inhibited in the excised leaves of cotton (Gossypium hirsutumL., var. DPL smoothleaf) (moderately tolerant) and soybean (Glycine maxMerr., var. Lee) (sensitive) by 2,4-bis(isopropylamino)-6-methylmercapto-s-triazine (prometryne) and the degree of inhibition increased with increasing herbicide concentration. Prometryne produced no significant effect on14CO2fixation during the dark period in either species except for some changes in the concentrations of aspartic and glyceric acids in soybean.
Matricaria and Lambsquarter Control in Brassicas with Analogs of Propachlor
Authors: Mukula Jaakko , Gentner W. A.
Published: June 2019

The compound 2-chloro-N-isopropylacetanilide (propachlor) and five analogs were evaluated for the control of matricaria (Tripleurospermum inodorum (L.) Schultz, syn. Matricaria inodora L.) and common lambsquarter (Chenopodium album L.) in turnip rape (Brassica rapa L.), rape (Brassica napus L.), kale (Brassica oleracea L., var acephala DC.), and rutabaga (Brassica napobrassica Mill). Chemicals were assayed by using nutrient solution culture techniques at rates of 10-4 through 10-8M. N-(butoxymethyl)-2-chloro-2',6'-diethylacetanilide and 2-chloro-N-(propoxymethyl)-2',6'-acetoxylidide appear useful for the control of matricaria in brassicaceous crops commonly grown in Scandinavia.
Effects of Several Herbicides on Yews and Japanese Maples
Authors: Danielson L. L. , May Curtis
Published: June 2019

Field plots of small well-rooted plants of yew [Taxus media Rehd., var. Hicks] and maple [Acer palmatum Thunb., var. Japanese maple] were treated annually for 3 years with 3-(3,4-dichlorophenyl)-1,1-dimethylurea [diuron], 2-chloro-4,6-bis(ethylamino)-s-triazine [simazine], 2-(2,4-dichlorophenoxy)ethyl sodium sulfate [sesone], dimethyl tetrachloroterephthalate [DCPA], isopropyl m-chlorocarbanilate [chlorpropham], α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine [trifluralin], 2-sec-butyl-4,6-dinitrophenol [dinoseb], and 3-amino-s-triazole [amitrole]. Commercial formulations of the herbicides were applied in water as a soil drench in May each year, at minimum effective dosage levels for weed control and at much higher levels. Diuron at herbicidally effective rates significantly reduced stand and growth of yew and maple plants. Simazine and sesone caused noticeable but variable reductions in growth of maple plants that were not statistically significant and yew plants were unaffected by these treatments. None of the other herbicides caused visible or measurable differences in growth.
Photocontrol of Rough Cinquefoil Seed Germination and its Enhancement by Temperature Manipulation and KNO3
Authors: Taylorson R. B.
Published: June 2019

Imbibed seeds of rough cinquefoil (Potentilla norvegica L.) remain dormant in darkness at constant and alternating temperatures. Full promotion of germination resulted after 3 days' dark imbibition at 25 C followed by 24 hr of continuous unfiltered fluorescent light. Germination was controlled by phytochrome. The sensitivity of the seeds to short light exposures was increased by the introduction of a temperature shift to 40 C for 2 hr, at the conclusion of the normal dark imbibition period at 25 C. The temperature shift also reduced the time required in continuous light to give full promotion of germination. The response to light was synergistically increased when the seeds were imbibed in 0.2% KNO3, and given the temperature shift. Nearly full promotion was reached with ca. 5 min of red light, and 50% germination occurred with as little as 1 sec. The system was still under phytochrome control. These findings suggest a mechanism by which soil populations of weed seeds may become physiologically conditioned to respond to very brief exposures to light.
Adsorption, Volatility, and Migration of Thiocarbamate Herbicides in Soil
Authors: Koren Ephraim , Foy Chester L. , Ashton Floyd M.
Published: June 2019

The relative adsorption and migration of four thiocarbamate herbicides were studied in five soil types. Pebulate (S-propylbutylethylthiocarbamate) was adsorbed to the greatest degree by any one of the soils or adsorbents used. EPTC (ethyl N-N-dipropylthiocarbamate) showed the least adsorption while ethyl N-ethyl-N-cyclohexylthiocarbamate (hereinafter referred to as R-2063) was intermediate. Charcoal and bentonite clay were very effective adsorbents while the soils varied in their ability to adsorb the herbicides. A correlation was found between the rate of adsorption and the amount of organic matter in the soil. Such correlation was not found with the clay content, but a multiple regression test showed that the clay content is also closely associated with adsorption. The leaching of EPTC, pebulate, R-2063, and S-2,3-dichloroallyl N,N-diisopropylthiolcarbamate (diallate) in soil columns was directly related to their solubilities in water and inversely related to the organic matter content of the soil. Incorporation of the herbicides into the upper 5 cm of the soil did not alter the pattern or depth of their leaching. The lateral diffusion of thiocarbamates in the soil was much more restricted than the leaching downward. Again, this movement was closely related to the water solubilities of the herbicides, to soil organic matter, and apparently to the vapor pressures of the herbicides. EPTC vapor loss was the greatest followed in order by pebulate and R-2063. The rate of vapor loss from soils of all of the herbicides tested was reduced when the soil properties enabled rapid infiltration and drying of the spray drops.
Woody Plant Shoot Management and Response to Herbicidal Treatment
Authors: Upchurch R. P. , Keaton J. A. , Coble H. D.
Published: June 2019

Shoots of naturally established, foliated red maple (Acer rubrumL.) and persimmon (Diospyros virginianaL.) growing in North Carolina were treated with 2,4-dichlorophenoxyacetic acid (2,4-D) or 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) formulations following various shoot management procedures. Shoot management prior to treatment consisted of decapitating or not decapitating shoots at 2 inches above the ground line in May when the plants were 3 to 6 ft high. Herbicidal applications were made to uncut shoots and to resprouts of previously cut shoots at 30 and 60 days after decapitation. Responses measured 10, 14, and 22 months after treatment were percent control or original shoots, percent control of new shoots, shoot height, number of live stems/plant. The original shoot and new shoot values were averaged to provide a total shoot control index. Spraying of previously cut shoots at 30 or 60 days after cutting was more effective than spraying of uncut shoots except for 2,4,5-T applied to persimmon. The average total shoot control index for 2,4-D treated red maple, considering all rates, application dates, and evaluation dates was 82% for previously cut shoots and 56% for uncut shoots while the corresponding heights were 0.9 and 4.2 ft, respectively. For 2,4,5-T-treated red maple, the total shoot control indices were 92% and 78% for previously cut and uncut shoots, respectively, while the corresponding heights were 0.4 and 1.4 ft. For persimmon, there was a net advantage for treating previously cut shoots with 2,4-D, but the reverse was true for 2,4,5-T. The results are consistent with the theoretical behavior of 2,4-D and 2,4,5-T in woody plants outlined as a basis for conducting the study. Alternate explanations of results are proposed and practical implications described.
Selective Grass Control with Siduron
Authors: Kerr Harold D.
Published: June 2019

Doses of 1-(2-methylcyclohexyl)-3-phenylurea (siduron), sprayed on seeds of several forage, turf, and weed grasses on the soil surface killed some weed grasses without injuring many desirable grasses. Seeds of tolerant grasses mixed with an excess of a dry siduron formulation and stored for 12 months germinated without injury, but crabgrass (Digitaria sanguinalis (L) Scop.) and barnyardgrass (Echinochloa crusgalli (L.)) were killed during germination. Siduron eliminated seedling weed grasses from seedling perennial turfgrasses when applied on the soil surface or incorporated in the soil just before planting. When applied as a coating on seeds of turfgrasses at planting time, siduron controlled some annual weed grasses without injurying the turfgrasses. Herbicidal action appeared to be localized mainly in the grass roots and differed from that of 1,1-dimethyl-3-phenylurea (fenuron) and isopropyl carbanilate (propham) applied at equimolar doses.
Effect of Activated Carbon on the Phytotoxicity of Herbicides in a Tropical Soil
Authors: Bovey R. W. , Miller F. R.
Published: June 2019

We studied the inactivation of herbicides applied to the soil by activated carbon in the greenhouse and field. Degree of inactivation depended upon herbicide type, dosage, plant species, and quantity of activated carbon applied. In greenhouse experiments with Toa silty clay, 2-chloro-4,6-bis(isopropylamino)-s-triazine (propazine) was inactivated at activated carbon: herbicide ratios of 66:1, whereas 4-amino-3,5,6-trichloropicolinic acid (picloram) required ratios of 3600:1. Beans (Phaseolus vulgaris L., var. Black Valentine) were used as a bioassay. In the field, activated carbon rates up to 600 lb/A did not completely prevent injury to oats (Avena sativa L., var. Markton), cucumbers (Cucumis sativus L., var. Ashly), and Black Valentine beans by propazine at 2.5 lb/A in Toa silty clay 0, 37, 72, and 93 days after herbicide application. Activated carbon protected oats from picloram at 0.5 lb/A but did not completely protect cucumbers or beans at rates up to 600 lb/A. Activated carbon in untreated herbicide soils was not harmful to growth of beans, oats, and cucumbers in Toa silty clay.
Atrazine Degradation in Two Soil Profiles
Authors: Roeth F. W. , Lavy T. L. , Burnside O. C.
Published: June 2019

Degradation of 2-chloro-4-ethylamino-6-isopropyl-s-triazine (atrazine) was studied in the 0 to 9, 14 to 24, and 36 to 48-inch depths of Sharpsburg silty clay loam and Keith silt loam soils. The effects of moisture, temperature, and microorganisms on degradation were observed. Atrazine was degraded two to three times faster in the topsoils than in the subsoils. Each 10 C temperature increase from 15 to 35 C caused the degradation rate to increase two to three times in these soils. Increasing the moisture content of the soils from 0.4 to 0.8 field capacity caused 14CO2 evolution from chain-labeled atrazine-14C treated soils to increase zero to six times. At 25 C and 0.8 field capacity, 100 to 194 atrazine molecules were detoxified for each molecule evolved as 14CO2 from chain-labeled atrazine. Solution culture studies showed cleavage of the side chain and ring of atrazine-14C except in the 14 to 24 and 36 to 48-inch depths of Keith silt loam.