No description available.

No description available.

No description available.

No description available.

Animal population ecology has become a rapidly expanding natural science over the past decade. This trend is the result of many interacting factors, not least among them being; the maturation of ecology from a more or less descriptive and a priori science to the beginnings of a quantitative, deductive-inductive approach; and, the need for a better understanding of the effect of pesticides and biological agents on the trend of pest populations. Such knowledge is almost completely lacking, although the work in Canada of R.F. Morris, E.J. LeRoux and their associates forms the basis of such a need. Obviously any quantitative study aimed at understanding the dynamics of any animal population, and hence the causes that account for changes in the rise and fall of such a population, must be a valuable addition to knowledge on this subject. [...]

The elm disease incited by Ceratocystis ulmi (Buism.) C. Moreau, generally named Dutch elm disease, especially in North America, was discovered in The Netherlands soon atter the first world war. The designation, Dutch elm disease, should be avoided, according to Westenberg (1932), because it is misleading. The name elm disease is used in this work, following in this respect the nomenclature adopted in the Annual Report of the Quebec Society for the Protection of Plants (Pomerleau, 1961). [...]

The fungus responsible for the downy mildew disease, common on commercially grown sunflowers, is Plasmopara halstedii (Farlow) Berl. et de Toni, one of the Peronosporaceae in the Oomycetes, known to be soil borne and to infect via the roots. [...]

Cotton (Gossypium spp. L.) is man's most important natural fibre crop. The world cotton production estimate for 1964-65 is 51.6 million bales from an estimated area of 81.6 million acres (Anonymous, 1965). The crop is grown in the warm areas of the tropical and sub-tropical regions of the world. [...]

The quantification of population and mortality data for insect pests of apple is necessary if we are to gain fundamental insight in the dynamics of insect populations of the orchard ecosystem. The need to quantify has recently been emphasized (LeRoux, 1964a; 1964b) and the greater application, practical and scientific, or the quantitative results obtained for agricultural and forest insect pests has been demonstrated (LeRoux et al., 1963). [...]

Corn is one of the three most valuable cereals in the world, and at present its adoption as a grain crop in Quebec is being encouraged. [...]