Studies of the Lecanium Scale, Eulecanium coryli (L.), and its Parasite, Blastothrix sericea (Dalm.), in British Columbia

1953 ◽  
Vol 85 (5) ◽  
pp. 153-181 ◽  
Author(s):  
K. Graham ◽  
M. L. Prebble
Keyword(s):  
British Columbia ◽  
Population Density ◽  
Chemical Control ◽  
Host Population ◽  
Severe Injury ◽  
Horse Chestnut ◽  
Main Area ◽  
Nursery Stock ◽  
Low Levels

The lecanium scale was introduced into Vancouver with nursery stock from England in 1903, and by 1910 had become firmly established. Severe injury to broad-leaved maple, vine maple and horse chestnut was reported in 1923, and chemical control operations were undertaken from 1924 to 1930, but with very transitory effects (9, 10). The encyrtid wasp, Blastothrix sericea (Dalm.), imported from England in 1928 and 1929, quickly became established at the liberation points in Sorth Vancouver, and by June, 1930 had dispersed over an area of about 20 square miles. In April, 1931, twigs with parasitized scales from North Vancouver were distributed at intervals throughout the main area of lecanium infestation south and east of Vancouver, and by June of that year the parasite was known to be established over an area of about 100 square miles. By 1932, the percentage of parasitism in the mature lecanium females reached 90 to 100 per cent, and host population density was at very low levels (12, 13).

Parasite infection and host dynamics in a naturally fluctuating rodent population

2012 ◽  
Vol 90 (9) ◽  
pp. 1149-1160 ◽  
Author(s):  
J.C. Winternitz ◽  
M.J. Yabsley ◽  
S.M. Altizer
Keyword(s):  
Population Density ◽  
Experimental Studies ◽  
Host Density ◽  
Positive Association ◽  
Population Cycles ◽  
Host Population ◽  
Reproductive Status ◽  
Vole Cycles ◽  
Host Infection ◽  
The Impact

Parasites can both influence and be affected by host population dynamics, and a growing number of case studies support a role for parasites in causing or amplifying host population cycles. In this study, we examined individual and population predictors of gastrointestinal parasitism on wild cyclic montane voles ( Microtus montanus (Peale, 1848)) to determine if evidence was consistent with theory implicating parasites in population cycles. We sampled three sites in central Colorado for the duration of a multiannual cycle and recorded the prevalence and intensity of directly transmitted Eimeria Schneider, 1875 and indirectly transmitted cestodes from a total of 267 voles. We found significant associations between host infection status, individual traits (sex, age, and reproductive status) and population variables (site, trapping period, and population density), including a positive association between host density and cestode prevalence, and a negative association between host density and Eimeria prevalence. Both cestode and Eimeria intensity correlated positively with host age, reproductive status, and population density, but neither parasite was associated with poorer host condition. Our findings suggest that parasites are common in this natural host, but determining their potential to influence montane vole cycles requires future experimental studies and long-term monitoring to determine the fitness consequences of infection and the impact of parasite removal on host dynamics.

The Caragana Aphid, Acyrthosiphon caraganae (Cholod.) in Western Canada, and its Separation from the Pea Aphid

1962 ◽  
Vol 94 (10) ◽  
pp. 1075-1077 ◽  
Author(s):  
A. G. Robinson ◽  
G. A. Bradley
Keyword(s):  
British Columbia ◽  
North America ◽  
Chemical Control ◽  
Pea Aphid ◽  
Annual Reports ◽  
Western Canada ◽  
Forest Insect ◽  
Disease Survey ◽  
Caragana Arborescens

Except for occasional references in the Annual Reports of the Forest Insect and Disease Survey of infestations of an aphid on caragana (Caragana arborescens Lam.) in Western Canada and a note on chemical control (Bradley, 1952), there is no published record known to the authors of the occurrence of the caragana aphid, Acyrthosiphon caraganae (Cholod.), in North America. MacNay (1953) summarized reports that severe infesrations of aphids, “probably mainly the caragana aphid”, occurred on caragana in 1952 in the East Kootenays of British Columbia, and at several places in Alberta and Saskatchewan. At some localities 100 per cent defoliation was reported.

Liver Glycogen Reserves of Interacting Resident and Introduced Trout Populations

1961 ◽  
Vol 18 (1) ◽  
pp. 125-135 ◽  
Author(s):  
P. W. Hochachka
Keyword(s):  
Population Density ◽  
Liver Glycogen ◽  
Salmo Gairdneri ◽  
Recovery Rates ◽  
Introduced Populations ◽  
Wild Trout ◽  
Low Levels ◽  
Glycogen Stores ◽  
Salmo Clarki

Three groups of trout, two introduced populations of Salmo gairdneri and a resident Salmo clarki, were studied in stream sections. Liver glycogen deposits, which were reduced to low levels during transportation to the stream, were restored in 2 to 3 weeks in all groups, with recovery rates being approximately inverse to the population density. Within the hatchery groups, larger fish laid down greater glycogen stores. Wild trout maintained their high glycogen reserves throughout the experiment.

scholarly journals SELECTION OF HERBICIDES TARGETING THE USE IN CROP SYSTEMS CULTIVATED WITH SHOWY CROTALARIA

2015 ◽  
Vol 33 (3) ◽  
pp. 521-534 ◽  
Author(s):  
G. B. P BRAZ ◽  
R. S OLIVEIRA JR ◽  
J. CONSTANTIN ◽  
H. K. TAKANO ◽  
C. A. CHASE ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Chemical Control ◽  
Clayey Soil ◽  
Chlorimuron Ethyl ◽  
High Production ◽  
Low Levels ◽  
Postemergence Herbicides ◽  
Potential Use ◽  
Selection Of

ABSTRACT The increase in the area planted with Crotalaria spectabilishas occurred by several factors, highlighting the potential to reduce the nematodes, nitrogen fixation and the high production of biomass. By becoming a species sown as a crop, it is necessary to control the weeds that coexist with showy crotalaria. This change in the use of this crop creates the possibility of this specie becoming a weed. The aim of this study was to assess the potential use of herbicides applied in preemergence and postemergence of C.spectabilisfor different purposes (control of volunteer and selectivity plants). Three experiments were installed in a greenhouse (two with herbicides applied in preemergence - in soils with distinct textural categories; and one experiment with herbicides applied in postemergence). The results of the experiments with herbicides applied in preemergence showed that: amicarbazone, atrazine, diuron, metribuzin, prometryn, fomesafen and sulfentrazone showed effectiveness for control of C.spectabilis in clayey soil. Besides these, flumioxazin and isoxaflutole also showed potential to be used in the control of showy crotalaria in soils with loam texture. In relation to the postemergence herbicides, atrazine, diuron, prometryn, flumioxazin, fomesafen, lactofen, saflufenacil, amonio-glufosinate and glyphosate can be used aiming the chemical control of C.spectabilis. Herbicides chlorimuron-ethyl, diclosulan, imazethapyr, pyrithiobac-sodium, trifloxysulfuron-sodium, clomazone, pendimethalin, S-metolachlor and trifluralin applied in preemergence, and imazethapyr, pyrithiobac-sodium, flumiclorac, bentazon and clethodim applied in postemergence caused low levels of injury to C.spectabilis plants, making necessary the development of new searches to ensure the selectivity of these products.

Lophodermium oxycocci. [Descriptions of Fungi and Bacteria].

2005 ◽  
Author(s):  
D. W. Minter
Keyword(s):  
British Columbia ◽  
Czech Republic ◽  
New Jersey ◽  
Geographical Distribution ◽  
Chemical Control ◽  
Vaccinium Macrocarpon ◽  
Economic Damage ◽  
Twig Blight

Abstract A description is provided for Lophodermium oxycocci. Information is included on the disease, cranberry twig blight, caused by the organism, that can cause serious economic damage to commercial cranberry crops in Oregon and Washington. Some information on cultural and chemical control is given, along with details of its transmission, geographical distribution (Canada (British Columbia), USA (Alaska, Maine, Massachusetts, Michigan, New Jersey, Oregon and Washington), Russia, Czech Republic, Finland, France, Germany, UK, Poland, Sweden and Ukraine) and hosts (Vaccinium macrocarpon, Vaccinium sp. and V. oxycoccus).

CHEMICAL CONTROL OF THE RASPBERRY ROOT BORER, BEMBECIA MARGINATA (HARR.), ON LOGANBERRY IN BRITISH COLUMBIA

1960 ◽  
Vol 40 (1) ◽  
pp. 160-164
Author(s):  
J. Raine ◽  
H. Andison
Keyword(s):  
British Columbia ◽  
Chemical Control ◽  
Early Instar

A single spray of 25 per cent Diazinon emulsible concentrate applied as a drench to loganberry crowns in March, April or October against early instar larvae of the raspberry root borer, Bembecia marginata (Harr.) reduced a severe infestation (77 per cent or more) to 4 per cent or less of the crowns. This outstanding control was obtained at rates as low as 2 pints per 100 gallons and 1/2 pint of drench per plant (43 gallons per acre). Applications in May at 2 pints of drench per crown reduced the infestation to 10 per cent. The following emulsible concentrates reduced the infestation to between 0 and 10 per cent: at 1 pint of drench per crown applied in October, lindane at 5 pints, Thimet at 1 pint, or 12008 at 1 pint per 100 gallons; at 2 pints of drench per crown applied in April, Sevin at 8 pints, NC262 at 1/2 pint, or Phosdrin at 1 pint per 100 gallons. The drenches apparently killed the early instar larvae which overwinter in hibernacula at the base of the canes until early April, and feed just beneath the bark in May. Thus damage to canes that would bear fruit the following year was prevented.

scholarly journals Evaluation of Foliar Fungicide Sprays for the Control of Boxwood Blight, Caused by the Fungus Cylindrocladium buxicola

2013 ◽  
Vol 14 (1) ◽  
pp. 2 ◽  
Author(s):  
B. Henricot ◽  
E. Wedgwood
Keyword(s):  
British Columbia ◽  
Chemical Control ◽  
Laboratory Tests ◽  
Winter Season ◽  
Curative Treatment ◽  
Cultural Methods ◽  
The Usa ◽  
Blight Disease ◽  
The Uk ◽  
Foliar Fungicide

Cylindrocladium buxicola causes a damaging blight disease on boxwood which has spread rapidly throughout Europe since introduction of the pathogen in England in the mid 1990s. The pathogen has also been recently identified in the USA and British Columbia. The disease is difficult to control using cultural methods and information about chemical control is lacking. To address this, preventative and curative foliar fungicide sprays previously shown in laboratory tests to have efficacy were evaluated over two autumn/winter seasons in the UK. Results from the first autumn/winter season showed that the premix product Opponent (epoxiconazole + kresoxim-methyl + pyraclostrobin) was the best treatment when applied preventatively 3 days before inoculation. In the second autumn/winter season, curative treatment of diseased plants was best achieved with a weekly program of fungicides starting 3 days before inoculation and alternating with two or three products including Bravo (chlorothalonil), Signum (boscalid + pyraclostrobin), and Octave (prochloraz). The only fungicide tested and available to amateur growers in the UK, Fungus Clear (penconazole), was found to give moderate control of boxwood blight. Accepted for publication 7 August 2012. Published 24 October 2013.

Fish population size, and not density, as the determining factor of parasite infection: a case study

Parasitology ◽  
2004 ◽  
Vol 128 (3) ◽  
pp. 305-313 ◽  
Author(s):  
A. M. BAGGE ◽  
R. POULIN ◽  
E. T. VALTONEN
Keyword(s):  
Species Richness ◽  
Population Density ◽  
Population Size ◽  
Fish Population ◽  
Host Population ◽  
Fish Length ◽  
Total Fish ◽  
Infection Parameters ◽  
The Mean

The diversity and abundance of parasites vary widely among populations of the same host species. These infection parameters are, to some extent, determined by characteristics of the host population or of its habitat. Recent studies have supported predictions derived from epidemiological models regarding the influence of host population density: parasite abundance and parasite species richness are expected to increase with increasing host population density, at least for directly transmitted parasites. Here, we test this prediction using a natural system in which populations of the crucian carp, Carassius carassius (L.), occur alone, with no other fish species, in a series of 9 isolated ponds in Finland. The ectoparasite communities in these fish populations consist of only 4 species of monogeneans (Dactylogyrus formosus, D. wegeneri, D. intermedius and Gyrodactylus carassii); the total and relative abundance of these 4 species varies among ponds, with one or two of the species missing from certain ponds. Across ponds, only one factor, total fish population size, explained a significant portion of the variance in both the mean number of monogenean species per fish and the mean total abundance of monogenean individual per fish. In contrast, fish population density did not influence either monogenean abundance or species richness, and neither did any of the other variables investigated (mean fish length per pond, number of fish examined per pond, distance to the nearest lake, and several water quality measures). In our system, proximity among fish individuals (i.e. host population density) may not be relevant to the proliferation of monogeneans; instead, the overall availability of host individuals in the host population appeared to be the main constraint limiting parasite population growth.

Spatial and temporal variation in the infracommunity structure of helminths of Apodemus sylvaticus(Rodentia: Muridae)

Parasitology ◽  
1989 ◽  
Vol 98 (1) ◽  
pp. 145-150 ◽  
Author(s):  
S. S. J. Montgomery ◽  
W. I. Montgomery
Keyword(s):  
Species Richness ◽  
Northern Ireland ◽  
Population Density ◽  
Resource Utilization ◽  
Species Interactions ◽  
Apodemus Sylvaticus ◽  
Host Population ◽  
Spatial And Temporal Variation ◽  
Time And Space ◽  
Animal Material

SummaryMean species richness and diversity of the helminth infracommunity of Apodemus sylvaticus in woodland areas of Co. Down, Northern Ireland, varied in time and space. Variation in infracommunity structure among individual hosts, however, always accounted for more than 60% of the variation in the data from different places or different times. Helminth species richness increased with increasing population density, the percentage of the host population 16 weeks old or older, and the proportion of the host population with animal material in their stomachs, at two sites monitored over 33 months. The basis for spatial variation in infracommunity structure is less certain but host dynamics and differences in diet are likely to play some role. It is concluded that analysis at the infracommunity level focuses closely on the potential for species interactions and overlap in resource utilization. Infracommunity structure, at least in the case of A. sylvaticus, varies markedly in time and space and between individual hosts. Such variation should not be ignored in comparative studies.

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