bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECT OF TETRACHLORONITROBENZENE ON THE SPROUTING AND CROPPING OF POTATO TUBERS
Authors: BROWN W. , REAVILL MARY J. 
Published: February 2008

Potato tubers dusted with a preparation containing 3% tetrachloronitrobenzene (TCNB) and kept in a nearly closed container in the laboratory showed reduced sprouting. The reduction was greater the lower the temperature and the earlier the application of the dust; it was less marked with tubers lying on a moist substratum. After long exposure, and especially at higher temperatures, sprouts of treated tubers tended to show a ‘witch's‐broom’ appearance. The repressive effect of TCNB on growth rate disappeared as soon as the tubers were brought into ordinary air. To a certain extent the action of TCNB was antagonized by treatment of the tubers with ethylene chlorhydrin.Replicated field experiments over three seasons, with four potato varieties, gave a measure of the check to bulking of the crop which is brought about by winter storage of seed tubers in presence of TCNB. This check was eliminated by airing the tubers before planting, the time necessary for this depending on conditions. An airing period of about 6 weeks, in an unheated greenhouse (apart from sun‐ heat) was found to be sufficient for this purpose.The speed of emergence of the variously treated batches was closely correlated with the yields produced, especially in the earlier liftings.The average number of shoots per plant was significantly increased by the dust treatment and this was reflected in a higher seed/ware ratio in the mature or late‐lifted crop.There was no evidence that the delay in sprouting brought about by TCNB was due to an effect on the respiration rate of the dormant tubers.The concentration of active principle was materially diminished in treated clamps after the period (c. 5 months) of winter storage. Estimates were also made of the persistence of TCNB on exposed surfaces in still and in moving air.
FIELD STUDIES ON THE INFLUENCE OF WEATHER ON EGG‐LAYING BY THE CABBAGE ROOT FLY, ERIOISCHIA BRASSICAE BCHÉ. II
Authors: MILES MARY 
Published: February 2008

Observations on the intensity and duration of egg‐laying by Erioischia brassicae Bché were continued in 1953 on the same site as in 1952. Eggs were first observed on 31 April and the spring peak period of egg‐laying lasted from 3 to 30 May with a daily average of 40 eggs/plant. The mean total in spring 1953 was 1287 eggs/plant. Summer peaks occurred on 1–20 July (average 17 eggs/day/plant) and 5–11 August (average 21 eggs/day/plant).In the field the threshold of reproduction was approximately 60° F. The rate of egg‐laying was highest at 65–70° F. and it declined during prolonged periods of higher temperatures.The annual cycle of generations, as shown by egg counts and confirmed by the examination of puparia, consisted of two generations and a partial third. The spring generation developed without a prolonged diapause, and there was complete emergence during the summer. The overwintering puparia came from the second and third generations of larvae.
ANALYSIS OF VIRUS LOCAL LESION EXPERIMENTS
Authors: FRY P. R. , TAYLOR W. B. 
Published: February 2008

Calculations based on variation of lesion counts about means within the range 7 to 260 per half‐leaf show that the standard deviation may be rendered independent of the mean by a transformation log (x+12) for half‐leaf experiments in bean, tobacco and Nicotiana glutinosa and log (x+21) for whole‐leaf experiments in bean.Half‐leaf experiment designs are superior to those using whole‐leaves.Balanced Incomplete Block designs are more efficient than Randomized Blocks or comparisons using a common standard.The use of covariance to remove the effect of leaf susceptibility gives increased accuracy over the treatment‐standard comparison if used with designs allowing removal of both plant variation and that due to leaf age.
ESTERASE INHIBITION BY ORGANO‐PHOSPHORUS RESIDUES, WITH SOME OBSERVATIONS ON POSSIBLE EFFECTS ON PLANT METABOLISM
Authors: LORD K. A. 
Published: February 2008

Organo‐phosphorus residues in tissues of sprayed plants were detected by estimating the esterase‐inhibiting activity of their leaf and root extracts. This method was used to examine the anti‐esterase effects of mangold plants that had been sprayed with Systox, parathion and Hanane. Extracts of leaves of these treated plants were shown to inhibit added choline esterase for some weeks after treatment. The enzymic hydrolysis of phenyl acetate by extracts of leaves and roots of mangold plants treated with these insecticides was reduced for varying periods of up to 8 weeks.Assays of parts of bean plants that had been sprayed with demeton‐S showed that anti‐esterase activity was limited to those parts that had been sprayed: tissues developed subsequent to spraying showed no such effects. Leaves sprayed about z months previously inhibited added choline esterase and showed reduced activity in hydrolysing phenyl acetate. There is some evidence that substances, possibly substrates in the plant enzyme systems affected, accumulate in treated leaves.
THE INCIDENCE AND CONTROL OF CAULIFLOWER MOSAIC IN BROCCOLI IN SOUTH‐WEST ENGLAND
Authors: JENKINSON J. G. 
Published: February 2008

Cauliflower mosaic in south‐west England is most prevalent where there is a sequence of brassica crops that overlap in time. Broccoli yields can be increased by using plants raised in seed‐beds separated by half a mile from old infected plants. Surrounding seed‐beds with crops of kale or barley decreased the incidence of mosaic even when the seed‐beds were only 5 yd. from infected plants.Most plants infected at harvest contract infection after transplanting. A plant infected in the seed‐bed or early in the growing season can produce a group of infected plants immediately around it, and almost as many farther away. Spread can occur in the same pattern from these secondarily infected plants.Loss of yield is correlated with the time plants are infected. Plants infected as seedlings produce little or no curd or seed, whereas those infected when nearing maturity yield almost as well as uninfected plants.The movement of alate aphids is positively correlated with the numbers of infectedplants, and symptoms in field plants generally appear 8–9 weeks after infection.Cauliflower mosaic virus occurs in strains distinguishable by the severity of symptoms they cause.
THE CONTROL OF FUSARIUM BLIGHT IN OAT SEEDLINGS WITH ANTAGONISTIC SPECIES OF CHAETOMIUM
Authors: TVEIT M. , WOOD R. K. S. 
Published: February 2008

Forty‐seven isolates representing twenty‐seven species of Chaetomium were tested for their ability to control seedling blight of oat seedlings caused by Fusarium spp., chiefly F. nivale (Fr.) Ces. In pot tests the majority of the isolates were ineffective, but certain isolates of Chaetomium cochliodes Pall, and C. globosum Kunze gave a large measure of control and were as effective as an organic mercury seed dressing. Control of disease was also obtained when living material was attached to the surface of oat seed and when infested seed was soaked in cell‐free filtrates from cultures of isolates which reduced disease in vivo.Substantial control of disease was obtained when infested seed was sown in soil to which cultures of C. cochliodes had been added 10 months previously. This antagonist was able to grow through unsterile soil in the presence of certain added substrates.The results of pot experiments were confirmed in field experiments.Isolates of Chaetomium which controlled disease in pot and field experiments were not strikingly antagonistic to Fusariirm nivale in pure culture on agar media.
THE ABSORPTION, BREAKDOWN AND SYSTEMIC BEHAVIOUR IN PLANTS OF 32P‐LABELLED DEMETON‐S
Authors: THOMAS W. D. E. , BENNETT S. H. , LLOYD‐JONES C. P. 
Published: February 2008

Investigations are described on the general behaviour of diethyl‐5‐(a‐ethylthioethyl) phosphorothiolate (demeton‐S) labelled with 32P, after leaf application to beans, apples and Coleus; and to the roots of beans growing in soil or sand.Following leaf application, three processes, evaporation, breakdown into toxic non‐volatile compounds, and absorption, occurred concurrently and effectively removed unchanged demeton‐S from the leaf surface within a few hours. The evaporation gave rise to a fumigant action on Aphis fubue. Both demeton‐S and its degradation products were absorbed, the former degrading rapidly within the tissue untreated foliage. In no instance following leaf application could any unchanged demeton‐S be found elsewhere in the plant. Analyses showed a higher proportion of primary toxic degradation products in the treated than in the untreated leaves.Translocation from treated leaves was never sufficient to kill aphids feeding on the Following root application to beans in soil or sand, aphids feeding on the shoot tips were killed after z days; unchanged demeton‐S was translocated following root application.Demeton‐S and its toxic derivatives appeared to move much more freely in xylem than in phloem tissue; movement from xylem to phloem must occur, but subsequent transport within the latter tissue is limited.Autoradiographic evidence confirmed the limited extent of movement within leaves.
FEEDING HABITS OF THE COTTON WHITEFLY, BEMISIA TAB AC I GENN. (HOMOPTERA: ALEYRODIDAE)
Authors: POLLARD D. G. 
Published: February 2008

The cotton whitefly, Bemisia tabaci Genn., is important in the Sudan first as the vector of leaf‐curl virus, and secondly because it, principally when immature, directly damages plants. It damages both leaf‐curl‐resistant and susceptible varieties, and during recent years the increase in DDT spraying against the cotton jassid has increased the numbers and importance of the cotton whitefly.The macroscopic effects of the nymphs on the leaves include: (I) ‘asal’ (honeydew), often produced in quantities sufficient to cover the leaves and contaminate the lint in open bolls; (2) chlorotic spots caused by the saliva of feeding nymphs removing chlorophyll and starch; (3) development of anthocyanin; (4) leaf shedding and a reduced growth rate.The stylets of nymphs on the lower leaf surface can reach the phloem, except when they follow a convoluted path. The stylets usually penetrate between the epidermal cells. Penetration through the parenchyma is predominantly intercellular, and the objective is the phloem. Stylets terminated in the phloem in 82% of examples examined, with the remainder ending in the parenchyma. Only one case of partial penetration of the xylem occurred. A stylet, or salivary, sheath is rare; it is a delicate structure with an annular construction. Stylet tracks occur rarely and indicate probing in the region of the phloem.Damage to the tissues is limited to slow chloroplast destruction and occasional plasmolysis; the phloem is neither blocked nor obviously damaged.
THE EFFECT OF DARKENING ON THE SUSCEPTIBILITY OF PLANTS TO INFECTION WITH VIRUSES
Authors: WILTSHIRE G. H. 
Published: February 2008

The susceptibility of French bean plants to infection by the Rothamsted strain of tobacco necrosis virus as measured by the local‐lesion method is increased by a rise in temperature and usually by darkening the plant before inoculation. If part only of a leaf is darkened, that part becomes more susceptible. Plants in full light also become more susceptible if carbon dioxide is removed from the air, whereas the susceptibility of plants in the dark is not altered.Darkening leaves decreases their content of malic, fumaric, succinic and glycolic acids and increases the content of citric acid; the content of oxalic and malonic acids remains constant. These changes occurred in winter and summer and whether or not darkening increased susceptibility.The effect on susceptibility of individual acids infiltrated into the leaf was measured in leaves kept in the light or in the dark before inoculation. None of the acids used produced any large change in susceptibility.
ON THE CONTROL OF POTATO‐ROOT EELWORM (HETERODERA ROSTOCHIENSIS WOLLENW.) BY CHLORINATED PHENOL AND p‐m‐ CRESOL IN SOLUBILIZED FORM*
Authors: STONE L. E. W. 
Published: February 2008

Solubilized phenols and cresols, applied at the rate of 1s gal./sq.yd. at 5% strength on light sandy loam, have killed up to approximately half the population of potato‐root eelworm in the top 8 in of soil. When nematicide distribution was aided by rotavation on the same site, yields were approximately doubled compared with untreated areas. The eelworm population in the soil also increased, but not so much as that where no treatment had been applied.Under cold glasshouse conditions on light loam, high‐volume methods have greatly increased the yield of tomatoes compared with untreated plots, but the soil population of potato eelworm has also risen. 20 gal. to the square yard of 0·5%p‐m‐ cresol is better than 10 gal. of 1% by both criteria.There is evidence of a slow kill of cyst contents in soil samples stored in the laboratory.The high‐volume type of soil drench is shown to be highly effective under laboratory conditions. The importance of the initial water content of the soil is demonstrated. The superiority of the 20 gal. treatment over the 10 gal. one is confirmed.Investigations on kill in depth by very large applications of dilute nematicide in the same cold glasshouse have demonstrated the part played by the rate at which the material is applied. The degree of kill in the 6–12 in. soil layer is still inadequate.The practical applications of this type of nematicide are briefly discussed.
THE EFFECT OF TEMPERATURE AND HUMIDITY ON THE RATE OF DEVELOPMENT AND MORTALITY OF TRIBOLIUM CASTANEUM (HERBST) (COLEOPTERA, TENEBRIONIDAE)
Authors: HOWE R. W. 
Published: February 2008

The speed of development and the developmental mortality of Tribolium castaneum were studied over a series of temperatures between 15 and 40°C. at 10, 30, 70 and 90% R.H. using wheatfeed as food.Eggs did not hatch at any humidity at 17·5°C. or less, nor at 10% R.H. at 40°C. At all other conditions about 80% of eggs hatched. Humidity does not affect the duration of the egg period. The effect of temperature on the egg period is shown graphically, the shortest period occurring at 37·5°C.Larvae fail to develop into normal adults at 20°C. and also fail at 90 and 30% R.H. at 40°C. At 20°C. and 70% R.H. pupae may be formed but they do not become normal adults. The rate of larval development is affected by both temperature and humidity. Development is quickest at the highest humidity used at any temperature and at 35°C. for each humidity. Larval mortality is less than 20% except at 40°C. and at combinations of low humidity and low temperature. The results correspond with published results using similar foodstuffs.Groundnuts were used as a food in a series of experiments at 30°C. and another series at 70% R.H. Larvae on this food were much more susceptible to the effects of humidity and were unable to develop at 20 or 40°C. at 70% R.H. In all conditions development was slower and mortality higher than on wheatfeed.The pupal period is not affected by humidity and is shortest at 37·5°C.The conditions in which Park found that cultures of T. castaneum became extinct, 24°C. and 30% R.H., lie inside the zone in which development is possible. The possible causes for this discrepancy are discussed.
THE VALUE OF GLASSHOUSE TESTS WITH SEEDLINGS IN SELECTING PLANTS TOLERANT TO BEET YELLOWS VIRUS
Authors: WATSON MARION A. , RUSSELL G. E. 
Published: February 2008

Commercial strains of sugar beet, and breeders' lines of Beta vulgaris and B. vulgaris subsp. maritima, were exposed to infection with SBY and SBYN strains of beet yellows virus, using varying numbers of Myzus persicae as vectors, so as to cause a wide range of symptoms. The severity of the symptoms was assessed by scoring for superficial veinal necrosis (‘etch’). All varieties of sugar beet tested were susceptible to infection, but the severity of the symptoms varied, particularly between the cultivated and wild beet types.The scores for severity of symptoms made in the glasshouse were positively correlated with similar scores made in a field experiment using two cultivated and two wild beet types. The symptom scores were also positively correlated with losses in root and sugar yields caused by the virus.
SEEDLING BLIGHT OF SUGAR‐CANE‐A NEW DISEASE CAUSED BY HELMINTHOSPORIUM SACCHARI BUTLER
Authors: LOVELESS A. R. , SMITH C. E. M. 
Published: February 2008

The fungus Helminthosporium sacchari Butler, known to be the cause of eye spot, a common air‐borne disease of sugar‐cane leaves, is now shown to be the cause of an undescribed seed‐borne disease of sugar‐cane seedlings. It is therefore suggested that the disease should be renamed eye spot and seedling blight of sugarcane.The symptoms of seedling blight are described, and the pathogenicity of the fungus to sugar‐cane seedlings is confirmed. Incidence of seedling blight is shown to be markedly affected by the growing conditions, and disease‐escape is common. The two most important factors predisposing seedlings to attack appear to be (i) the relative humidity of the atmosphere, and (ii) the occurrence of a check to the continuous growth of the seedlings.With the discovery of the existence of seedling blight, eye spot assumes a particular significance in plant‐breeding plots, because it may be responsible for the loss of sugar‐cane seedlings, any one of which is potentially a desirable new variety.
THE CONTROL OF LOOSE SMUT IN WHEAT AND BARLEY
Authors: BATTS C. C. V. 
Published: February 2008

Loose smut (Ustilago nuda) has become increasingly troublesome in some widely grown wheat and barley varieties in recent years. The usual control of the disease is hot water treatment of the grain, and experiments have been carried out to find the most satisfactory treatment. Variations in times and temperatures for each stage of the treatment were made.In preliminary small‐scale experiments, the moisture content of the grain after different periods of soaking in water was determined, together with the effects on such grain of subsequent treatment at increasing temperatures. Wheat was able to withstand higher temperatures than barley.After presoaking in cold water for 4 hr. a draining period of 3 hr. helped considerably in controlling the disease. After a warm presoak (c. 90° F.) for 4 hr. the long drain was not necessary. The temperature of the grain in the hot tank must rise as rapidly as possible. Following the presoaking periods, 10 min. in the hot tank at 127–129° F. for wheat and 124–126° F. for barley were found to give control. Single tank treatments, e.g. 4 hr. at 113° F., also gave control.In general, the higher the temperature at any stage of the treatment, the greater the reduction in germination. The reduction in vigour was reflected in the percentage germination after j days.When sown, the plants from hot‐water‐treated seed were a few days later in appearing above ground compared with plants from untreated seed. After a week or two, however, no differences were visible. The tiller populations after earing were not closely related to the original germination percentage of the seed; plots which were thin in the early stages often tillered well.The effects of soaking in chloranil (Spergon) suspensions and in water alone was also investigated, the recommendations of Tyner being followed. No control was achieved in wheat by either treatment, but for barley both treatments gave control, but sometimes with serious reduction in germination.
THE EFFECT OF TEMPERATURE ON INFECTION WITH STRAINS OF CUCUMBER MOSAIC VIRUS
Authors: HITCHBORN J. H. 
Published: February 2008

Cucumber mosaic virus strains differed in their ability to multiply in plants at 37° C. Some strains multiplied in inoculated leaves and produced systemic symptoms in plants at this temperature; plants systemically infected with one such strain remained infected after prolonged treatment at 37° C. Other strains did not appear to multiply in inoculated leaves at 37° C. and heat treatment was successful in freeing plants from infection with these. Tests with one strain of each type showed both to be rapidly inactivated in expressed sap at 37° C.Strains of cucumber mosaic virus forming small necrotic local lesions in leaves of french bean var. Canadian Wonder, produced many fewer lesions in plants kept after inoculation at 25° C. for 24 hr. and then at 15° C. than in plants kept continuously at the lower temperature.
THE EFFECT OF DIFFERENT HOST PLANTS OF POTATO VIRUS C IN DETERMINING ITS TRANSMISSION BY APHIDS
Authors: WATSON MARION A. 
Published: February 2008

A stock of potato virus C derived from Edgecote Purple potatoes in 1945 was not then transmitted by aphids, although more than 2000 aphids were used in conditions optimal for transmitting the serologically related potato virus Y. This stock of virus C has been propagated continuously since, by manual inoculation in a series of Nicotiana glutinosa and N. tabacum, and in 1955 it was transmitted by the aphid Myzus persicae (Sulz.): about one in twenty of the aphids transmitted it compared with one in two for potato virus Y.Virus C derived from the Edgecote Purple potatoes in 1955 was not transmitted by aphids; both stocks of virus C produced only local lesions in Majestic potato leaves, and gave similar symptoms in tobacco.When inoculated to Majestic potatoes and then returned to tobacco plants, potato virus C usually ceased to be aphid transmitted and did not recover this property in any of the subsequent subcultures.Transmission from stock by aphids did not isolate a strain of virus C which was any more readily transmitted by aphids, indeed, for the first two or three subcultures, aphids usually transmitted more readily from plants inoculated manually. But the few isolates which remained aphid transmissible, after a second passage through potato, were rather readily transmitted.These results suggest that the ability of a virus to be aphid transmitted is, at least in part, determined by the host plant in which it is multiplying, but the nature of the changes which determine this ability are unknown.
METHODS FOR THE STUDY OF BLOWFLY POPULATIONS
Authors: MacLEOD JOHN , DONNELLY JOSEPH 
Published: February 2008

The advantages and disadvantages of laboratory‐bred material for fly‐marking experiments are discussed. Experimental evidence suggests that the tendency to uniformity of history of laboratory‐bred blowflies in relation to protein‐feeding produces no rhythm, apparent in the first 4 days at least, in their response to protein bait attractants.The change from insectary environment to field conditions may sometimes result in either a greater or a lower proportionate recapture of a laboratory‐bred sample than that for a comparable wild‐caught sample. The nature of the difference is apparently associated with the weather conditions of the release area, but may be due to other causes, probably including physiological debilitation of laboratory‐maintained strains.