摘要:

The biology ofPodisus serieventrisUhler, and its role in an outbreak of the black-headed budworm,Peronea varianaFernald, in Cape Breton, N.S., are described from studies carried on in 1930 and 1931. There is but one complete generation ofPodisusa year, and adults of both sexes hibernate. The eggs are laid in late June, July and early August, the incubation period ranging between 10 and 15 days. There are five nymphal stages, requiring about 45 days, on the average, for the attainment of the adult condition. In these respects particularly, the life history ofPodisus serieventrisin Cape Breton differs from its life history in Massachusetts, where four nymphal stages and three annual generations and the hibernation of females only, have been reported.The species conforms satisfactorily to Dyar's Law, the average growth ratio of individuals studied in 1931 being about 1.28. The first-stage nymphs feed on unhatched eggs of their own species, and upon the juices of coniferous and deciduous foliage, but were not induced to feed upon small caterpillars. Nymphs were able to complete the first instar on a purely vegetable diet, but died before the second moult when the same diet was continued. Older nymphs, fed for some time on animal food, were not able to attain the adult condition when supplied with plant food alone. This indicates the dependence of the species upon animal food; the food consumption of the various stages is briefly summarized. Evidence is presented which suggests the utilization, byPodisus, of a toxic secretion in overcoming their prey.The rather limited value ofPodisusas a control factor in the outbreak ofPeronea varianain 1930 and 1931 is described. The decline of thePeroneapopulation in 1931 caused a corresponding mortality in thePodisuspopulation, by starvation.

ISSN:1923-4287    

DOI:10.1139/cjr33-061

出版商:NRC Research Press    

年代:1933

数据来源: NRC

摘要:

Through the use of a dye solution, evidence was obtained that a liquid disinfectant may be forced into the narcissus bulb parts invaded by nematodes and fly larvae by immersionin vacuo.An investigation of the lethal properties of solutions against nematodes and their influence upon bulb growth led to the selection of a silver nitrate solution as a promising disinfectant, but owing to instability of silver nitrate in the presence of chlorides and other substances in tap water and in dirt clinging to bulbs, its use had no commercial possibilities. However when silver salt was combined with potassium cyanide in the ratio of 1 to 3 by weight, an effective solution of satisfactory stability was obtained.A solution of silver nitrate 0.05% and potassium cyanide 0.15% by weight, forced into narcissus bulbs by an evacuation process, effectively destroyed bulb nematodes and bulb fly larvae without significant injury to bulb growth under greenhouse conditions.Field tests with bulbs treated in silver nitrate-potassium cyanide solutions resulted in the reduction of infection from 26.8 to 1%, a 96% control, and no evidence of injury in the foliage or bloom was detected.

ISSN:1923-4287    

DOI:10.1139/cjr33-062

出版商:NRC Research Press    

年代:1933

数据来源: NRC

摘要:

Barley is suggested as a detector crop for the presence of living nematodes,Tylenchus dipsaci, in soil, owing to rapid development of nematode disease symptoms on barley.A satisfactory source of inoculum consists of the white masses of coiled nematodes that can be seen when the basal plate is removed from badly diseased narcissus bulbs. These masses remain viable for six months or longer when removed from the bulbs.Low temperatures and high light conditions favor the development of the nematode disease symptoms in barley seedlings, after nematodes are transferred from narcissus bulb to autoclaved soil planted with barley. Such barley seedlings were broad-leaved and stocky. Under low light and high temperatures, conditions that favor the development of spindly seedlings, the nematode disease symptoms are inconspicuous or absent.Few chemicals appear to be lethal to the bulb nematode. Of 100 tested only phenol, silver nitrate, and potassium or sodium bisulphite were lethal at dilute concentrations.

ISSN:1923-4287    

DOI:10.1139/cjr33-063

出版商:NRC Research Press    

年代:1933

数据来源: NRC

摘要:

A new disease of loganberry, an anther and stigma blight, is reported from British Columbia. This disease is caused byHapalosphaeria deformansSyd., a new fungus for North America. The fungus prevents pollination of a number of the drupelets and a deformation of the fruit results.

ISSN:1923-4287    

DOI:10.1139/cjr33-064

出版商:NRC Research Press    

年代:1933

数据来源: NRC

摘要:

The casein-splitting ability of each of seven cultures isolated from Kingston cheese has been studied. The cultures are Gram positive non-gelatin-liquefying coccus forms; some appear as chains in young milk culture, others as pairs. The methods of Orla-Jensen and Wasteneys and Borsook were used.It is shown that: (a) Cultures EMB2166 and 168 fail to attack casein; (b) the casein-splitting abilities of cultures EMB1131, 133, 173, 195 and EMB2173 are established and well-defined; (c) the type of proteolysis characteristic of cultures EMB1173 and 195 leads to the formation of large amounts of the simpler degradation products, whereas the proteolytic breakdown characteristic of cultures EMB1131, 133 and EMB2173 is not as complete; (d) culture EMB2173 is distinct in its casein-splitting abilities, as is evident when the results obtained by the two methods are compared; (e) unable to attack casein, cultures EMB2166 and 168 attack the non-protein-nitrogenous components of milk; (d) culture EMB2166 may be capable of protein synthesizing action.

ISSN:1923-4287    

DOI:10.1139/cjr33-065

出版商:NRC Research Press    

年代:1933

数据来源: NRC

摘要:

The effects of radiant energy as procured from a mercury arc, using full irradiation of varying intensity and using also individual wave-lengths transmitted by a monochromatic illuminator, have been determined. The enzymes investigated are the diastases (amylases) of saliva and of malt and the production, first of erythrodextrin and second, of maltose from starch, is used as an indicator of the enzyme activity. These two phases are designated the dextrinogenic and the saccharogenic. Full irradiation retards the dextrinogenic and the saccharogenic activity of both salivary and malt diastase in an inverse relation to intensity. In the case of salivary diastase the rates of dextrin production and of maltose production are decreased by the green and the far ultraviolet wave-lengths, while both tend toward stimulation when irradiated with the red yellow and near ultra-violet wave-lengths. The monochromatic effects on malt diastase are generally inhibitory for the dextrinogenic phase and stimulatory for the saccharogenic phase. These results may be explained by the presence of two enzymes constituting the diastase, one dextrinogenic, the other saccharogenic; either may be the less active and so become the "pace setter" for maltose production; in the dextrinogenic phase one only is considered, in the saccharogenic phase, both are involved; in salivary diastase the dextrinogenic enzyme is the "pace setter", while in malt diastase the saccharogenic enzyme is usually the "pace setter"; full illumination, however, retards the dextrinogenic enzyme until it becomes the "pace setter". The effects of monochromatic light on the growth of paramecium parallel the effects on the activity of salivary diastase and the effects of monochromatic light on the sporulation ofColletotrichumparallel the effects on the saccharogenic activity of malt diastase.

ISSN:1923-4287    

DOI:10.1139/cjr33-066

出版商:NRC Research Press    

年代:1933

数据来源: NRC

摘要:

The surface tension-temperature relations of methyl ether and propylene have been investigated by the capillary rise method over a range of temperatures approaching more closely to the critical temperature than has hitherto been done. From the data obtained, it has been concluded that the molecular surface energy does not become equal to zero when the meniscus is no longer visible, since the surface tension-temperature curves obtained apparently did not become asymptotic to the temperature axis at the critical temperature, the latter being considered as the temperature at which the meniscus is no longer discernible by the wave-lengths of visible light. The angle of interception of the surface tension-temperature curve with the temperature axis has been interpreted as indicating a discontinuity in properties at the critical point.The data obtained have also been applied to the examination of various relations involving surface tension. The Katayama equation has been shown to be considerably more accurate than that of Ramsay and Shields. Sugden's equation, has been found valid over the ranges of temperature investigated. The Macleod relation has also been examined, and an increase in the Macleod constant with increase in temperature shown to occur in the case of propylene, while no marked or progressive increase was noticed in the case of methyl ether. Calculation of the parachors served to emphasize the difference in behavior of the two substances in this respect. By a consideration of available data on benzene, chlorobenzene, and carbon tetrachloride, together with those obtained in this investigation, the increase of parachor in the case of those substances having unsaturated linkages in their molecular structure has been ascribed to increased electronic interaction with increased temperature. This is analogous to an increase in unsaturation.An attempt was made to adapt the ring method to the investigation of surface tension in the critical region, by measuring the force necessary to effect removal of the ring from the surface of the liquid by means of a calibrated quartz spiral. Although the method was unsatisfactory for the problem at hand, the feasibility of the method has been demonstrated. From the data obtained it has been possible to verify the zero angle of contact between methyl ether and glass.

ISSN:1923-4287    

DOI:10.1139/cjr33-067

出版商:NRC Research Press    

年代:1933

数据来源: NRC

摘要:

Tricin is identical with 5,7,4′-trihydroxy-3′,5′-dimethoxyflavone which has been synthesized by the action of concentrated sulphuric acid on 5,7-dihydroxy-3′,4′,5′-trimethoxyflavone. The constitution has been confirmed by fusion with alkali which yielded syringic acid and phloroglucinol.

ISSN:1923-4287    

DOI:10.1139/cjr33-068

出版商:NRC Research Press    

年代:1933

数据来源: NRC

摘要:

This paper is a continuation of recent work by H. L. Bronson, H. M. Chisholm, and the author (3) on the specific heats of tungsten, molybdenum, and copper from 0° to 500 °C. The "method of electrical heating" and adiabatic calorimetry have been extended to determine the specific heat of copper from −78° to 0 °C.The equation previously given for the specific heat of copper contained only the first two terms of the Debye expansion and was found not to hold below −30 °C. The following equation containing four terms of the Debye expansion fits the experimental curve from −78° to 500 °C. with a maximum deviation of only about 0.05%,where the units are joules per gram per °K. The constants of this equation were determined empirically and their close relation to theoretically expected values has been discussed.

ISSN:1923-4287    

DOI:10.1139/cjr33-069

出版商:NRC Research Press    

年代:1933

数据来源: NRC

摘要:

In this paper is presented a table of the various elements of terrestrial magnetism at Ottawa from 1500 to 1930 and explains how the values were derived from old magnetic observations made in America, and not from theory. Among other points, it shows that though the total magnetic force has been declining at Ottawa for some time, yet the total magnetic force and the magnetic elements evidently go through cycles and none have apparently suffered permanent change during the time considered.

ISSN:1923-4287    

DOI:10.1139/cjr33-070

出版商:NRC Research Press    

年代:1933

数据来源: NRC