Studies of Predators of the Balsam Woolly Aphid, Adelges piceae (Ratz.) (Homoptera: Adelgidae) VIII. Syrphidae (Diptera),

1960 ◽  
Vol 92 (11) ◽  
pp. 801-811 ◽  
Author(s):  
N. R. Brown ◽  
R. C. Clark
Keyword(s):  
Life Histories ◽  
Population Fluctuations ◽  
Term Study ◽  
Control Value ◽  
Long Term Study ◽  
Introduced Predators ◽  
Woolly Aphid ◽  
Adelges Piceae ◽  
And Control

Several species of native syrphids have been found to prey upon the introduced balsam woolly aphid, Adelges piceae (Ratz.), in New Brunswick and three of these, Syrphus torvus O. S., Metasyrphus lapponicus (Zett.), and Neocnemodon coxalis (Curr.), are sometimes very common. As part of a long-term study of the biological control of the balsam woolly aphid by native and introduced predators, the life histories, natural control, population fluctuations and control value of these native syrphids have been investigated.

Studies of Predators of the Balsam Woolly Aphid Adelges piceae (Ratz.) (Homoptera: Adelgidae): IX. Pullus impexus (Muls.) (Coleoptera: Coccinellidae), An Introduced Predator in Eastern Canada,

1961 ◽  
Vol 93 (12) ◽  
pp. 1162-1168 ◽  
Author(s):  
R. C. Clark ◽  
N. R. Brown
Keyword(s):  
Control Program ◽  
Natural Control ◽  
Eastern Canada ◽  
Control Value ◽  
Large Numbers ◽  
Woolly Aphid ◽  
Adelges Piceae ◽  
Available Information ◽  
And Control ◽  
Lower Population

Pullus impexus (Muls.) is one of many species of predators that have been introduced into Eastern Canada since 1933 as part of a biological control program against the balsam woolly aphid, Adelges piceae (Ratz.) Delucchi (1954) has published many details of the systematics, biology, and natural control of this species in Europe where he found it to be associated with all A. piceae infestations. According to Pschorn-Walcher and Zwölfer (1960), it is one of a group of predators that are usually associated with lower population densities of A. piceae and other related adelgids, rhan are Aphidoletes thompsoni Möhn and Laricobius erichsonii Rosen. Because it is common on adelgid infestations in Europe and because it can easily be reared en masse, large numbers have been released in North America. The purpose of the present paper is to bring together available information on releases, life-history and natural control, and control value of this species, obtained from studies carried out over the past nine years in New Brunswick.

scholarly journals Comparison of Hexavalent Chromium Leaching Levels of Zeoliteand Slag-based Concretes

2017 ◽  
Vol 12 (1) ◽  
pp. 29-36
Author(s):  
Jozef Oravec ◽  
Adriana Eštoková
Keyword(s):  
Portland Cement ◽  
Hexavalent Chromium ◽  
Construction Materials ◽  
Term Study ◽  
Granulated Blast Furnace Slag ◽  
Long Term Study ◽  
Leaching Parameters ◽  
And Control ◽  
Furnace Slag

Abstract In this experiment, the reference concrete samples containing Portland cement as binder and the concrete samples with the addition of ground granulated blast furnace slag (85% and 95%, respectively as replacement of Portland cement) and other samples containing ground zeolite (8% and 13%, respectively as replacement of Portland cement) were analyzed regarding the leachability of chromium. The prepared concrete samples were subjected to long-term leaching test for 300 days in three different leaching agents (distilled water, rainwater and Britton-Robinson buffer). Subsequently, the concentration of hexavalent chromium in the various leachates spectrophotometrically was measured. The leaching parameters as values of the pH and the conductivity were also studied. This experiment clearly shows the need for the regulation and control of the waste addition to the construction materials and the need for long-term study in relation to the leaching of heavy metals into the environment.

scholarly journals A long-term study of Rattus norvegicus in the London Borough of Enfield using baiting returns as an indicator of sewer population levels

2000 ◽  
Vol 125 (2) ◽  
pp. 441-445 ◽  
Author(s):  
D. CHANNON ◽  
M. COLE ◽  
L. COLE
Keyword(s):  
Rattus Norvegicus ◽  
Decomposition Analysis ◽  
Population Fluctuations ◽  
Term Study ◽  
Data Set ◽  
Sewerage System ◽  
Long Term Study ◽  
Base Time ◽  
Underlying Trend

This is a long-term study that investigates the dynamics of a population of Rattus norvegicus (Berk) inhabiting a sewerage system in London. Thirteen years (1986/7–1998/9) of data from sewer baiting records were analysed (a total of 35478 records). Manholes were baited with the anticoagulant Brodifacoum (0·005%) on a pinhead oatmeal bait base. Time series analysis was conducted on the data set to determine the underlying trend of the data and the population fluctuations about this trend. An exponential curve was found to give an accurate and realistic fit to the data and indicated that the rat population had decreased over the study period. Decomposition analysis indicated a 5-year cycle best described fluctuations around this trend.

Quinapril for Sclerosis Failed in Long-Term Study

2007 ◽  
Vol 38 (6) ◽  
pp. 14
Author(s):  
DAMIAN MCNAMARA
Keyword(s):  
Term Study ◽  
Long Term Study
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