The Influence of Spray Programs on the Fauna of Apple Orchards in Nova Scotia. XI. Effects of Low Dosages of DDT on Predator Populations

1962 ◽  
Vol 94 (2) ◽  
pp. 204-216 ◽  
Author(s):  
F. T. Lord
Keyword(s):  
Population Dynamics ◽  
Nova Scotia ◽  
Prey Density ◽  
Apple Orchards ◽  
Laboratory Investigations

The varied interpretations by numerous biologists, of the role of predation in population dynamics have been critically reviewed by Holling (1959) and by Huffaker and Kennett (1956). They conclude that the processes of predation may serve to regulate prey density and disagree with generalizations that minimize the role of predation. This role has been a subject of considerable interest in recent years, notable contributions being the laboratory investigations of Collyer (1958) and Huffaker (1958), and the field studics of Holling (1959).

The Application of Ecological Principles to Orchard Entomology in Canada

1964 ◽  
Vol 96 (1-2) ◽  
pp. 348-356 ◽  
Author(s):  
E. J. LeRoux
Keyword(s):  
Population Dynamics ◽  
Precise Measurement ◽  
Natural Populations ◽  
Future Research ◽  
Pest Species ◽  
Apple Orchards ◽  
Mortality Factors ◽  
Ecological Principles ◽  
Insight Into

AbstractA knowledge of ecological principles is essential to the successful development of future research on pest control problems in Canadian orchard entomology. Such knowledge should be especially helpful in spotlighting omissions in past studies as well as indicating new areas of study in the future. In particular, the ecosystem concept should serve not only as a basis for evaluating and bringing together existing data but also as a guide in the collection, integration and interpretation of new data.Our approach should be to study the population dynamics of major arthropod pests in Canadian apple orchards to obtain data of the fundamental kind on natural populations of these species. Since this approach is dependent on precise measurement of the population and its mortality factors, as well as on the mathematical modelling of the data obtained, unambiguous deduction and greater understanding and utilization of the results would then be possible.Examples from a recent eight-year study of the population dynamics of two pest species in Canadian apple orchards reveal that the fundamental approach to pest problems in Canada is both feasible and practical, and that the results can yield considerable insight into the role of mortality factors in population regulation as well as in control of pest stages of economic importance.

The Role of Ecopedological Parameters in Management Sustainability of Banat Lands

2018 ◽  
Vol 69 (3) ◽  
pp. 688-692
Author(s):  
Lucian Nita ◽  
Dorin Tarau ◽  
Gheorghe Rogobete ◽  
Simona Nita ◽  
Radu Bertici ◽  
...  
Keyword(s):  
Plant Nutrition ◽  
Physical State ◽  
Agricultural Land ◽  
Soil Characteristics ◽  
South West ◽  
Short And Long Term ◽  
Laboratory Investigations ◽  
Case Basis

The issue addressed relates to an area of 1891694 ha of which 1183343 ha are agricultural land (62, 56) located in the south-west of Romania and refer to the use of soil chemical and physical properties as an acceptor for certain crop systems, with minimal undesirable effects both for plants to be grown, as well as soil characteristics and groundwater surface quality. It is therefore necessary on a case-by-case basis, measure stoc or rect the acidic reaction by periodic or alkaline calculations, the improvement of plant nutrition conditions through ameliorative fertilization and the application of measures to improve the physical state, sufficient justification for the need to develop short and long term strategies for the protection and conservation of edifying factors and the need to respect the frequency of field and laboratory investigations at all 8x8 km grids of the National Soil-Grounds Monitoring System (organized by I.C.P.A.) and completing it with the relevant pedological and agrochemical studies.

scholarly journals Do males matter? The role of males in population dynamics

Oikos ◽  
2007 ◽  
Vol 116 (2) ◽  
pp. 335-348 ◽  
Author(s):  
Daniel J. Rankin ◽  
Hanna Kokko
Keyword(s):  
Population Dynamics

PREY PREFERENCES OF ADULT AND IMMATURE ZETZELLIA MALI EWING (ACARI: STIGMAEIDAE) AND TYPHLODROMUS CAUDIGLANS SCHUSTER (ACARI: PHYTOSEIIDAE)

1993 ◽  
Vol 125 (5) ◽  
pp. 967-969 ◽  
Author(s):  
David R. Clements ◽  
Rudolf Harmsen
Keyword(s):  
Biological Control ◽  
Potential Role ◽  
Panonychus Ulmi ◽  
Economic Damage ◽  
Apple Orchards ◽  
Effective Management ◽  
Phytoseiid Mites ◽  
Prey Preferences ◽  
Eriophyid Mites

Effective management of the interactions within the mite community is critical to biological control of economically damaging phytophagous mites such as Panonychus ulmi Koch (Tetranychidae) (Clements and Harmsen 1990). Although much is known about the potential role of phytoseiid mites in controlling P. ulmi (Dover et al. 1979), mites from at least seven other families may be present in apple orchards (Thistlewood 1991). Stigmaeid mites are predators which may play a beneficial role in biological control in conjunction with phytoseiids (Clements and Harmsen 1992). Eriophyid mites are phytophagous but seldom cause economic damage, and may compete with tetranychids and provide alternative food for predators of tetranychids (Croft and Hoying 1977).

Role of Host Plants in Population Dynamics of Stink Bug 1 Pests of Soybean in South Carolina 2

1982 ◽  
Vol 11 (4) ◽  
pp. 867-875 ◽  
Author(s):  
Walker A. Jones ◽  
M. J. Sullivan
Keyword(s):  
Population Dynamics ◽  
South Carolina ◽  
Host Plants ◽  
Stink Bug

PREDATION BY INSECTS AND SPIDERS INHABITING COLONIAL WEBS OF HYPHANTRIA CUNEA

1972 ◽  
Vol 104 (8) ◽  
pp. 1197-1207 ◽  
Author(s):  
R. F. Morris
Keyword(s):  
Population Dynamics ◽  
Nova Scotia ◽  
North America ◽  
Population Density ◽  
New Brunswick ◽  
Numerical Response ◽  
Initial Number ◽  
Hyphantria Cunea ◽  
The North ◽  
The Mean

AbstractThe number of predators inhabiting nests of Hyphantria cunea Drury was recorded annually for 13 years in four areas in New Brunswick and two areas on the coast of Nova Scotia. The most common groups were the pentatomids and spiders, which sometimes reproduced within the nests, but the mean number per nest was low in relation to the number of H. cunea larvae in the colonies. The rate of predation on fifth-instar larvae was low. Small or timid predators appeared to prey largely on moribund larvae or small saprophagans during the principal defoliating instars of H. cunea.No relationship could be detected between the number of larvae reaching the fifth instar and the number of predators in the colony; nor could any functional or numerical response of the predators to either the initial number of larvae per colony or the population density of colonies be found. It is concluded that the influence of the nest-inhabiting predators is small and relatively stable, and may be treated as a constant in the development of models to explain the population dynamics of H. cunea.H. cunea is a pest in parts of Europe and Asia, where it has been accidentally introduced from North America. The introduction to other continents of the North American predator, Podisus maculiventiis (Say), is discussed briefly.

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