C. B. Huffaker

Ecosystem management for supression of vectors of human malaria and schistosomiasis

Abstract Ecologically oriented tactics to present systems of controlling biological vectors of human schistosomiasis and malaria are discussed. Weaknesses and failures of current operations for suppression of vectors of these maladies and discussion of various alternative approaches are presented. No attempt is made to deal in depth with practices such as source reduction, cultural controls, vector exclusion, etc., although the general importance and some examples of these are cited. More emphasis is given to useful or potentially useful biological control tactics and the feasibility of combining them with general control programs. The authors stress the need to integrate these tactics into the entire economic, political and environmental context of affected societies looking toward long-term solutions. Successes in control of these diseases reported by the Peoples Republic of China are discussed as a possible pattern for other societies to adapt to their own needs.

Vegetational Correlations with Vapor Pressure Deficit and Relative Humidity

Ecologists have long attempted to single out critical environmental factors for use in distributional, successional, and other ecological studies. Temperature and relative humidity have been foremost in consideration. In recent years the importance of relative humidity, and even of temperature, has been minimized. The evaporating power of the air is looked upon as a far more critical factor for plants. The paucity of evaporation records and the lack of widely acceptable methods for measuring evaporation have prompted the consideration of factors which can be used in lieu of atmospheric evaporating power.

Biological control in the management of pests

Abstract In this paper the author reviews the broad general picture of developments in biological control in relation to the increasing opportunities presented for its employment in developing programmes of integrated pest control worldwide. Included are not only the classical examples of biological control of insects and mites and of weeds but such other areas as biological control of vertebrates, of plant diseases, and of dung accumulations, and as well the development of crop plant varieties resistant to plant disease. The review is developed as a means of illustrating that biological control offers real potential as a major manipulatable tactic for central use and maximization in a strategy of integrated control of pests in a great variety of situations — on land and in water, from the tropics to cold, temperate and sub-arctic regions, in forests and range and in cultivated crops and ornamental plantings. It is noted that the employment of these biological control tactics are often self-sufficient but they are not expected to broadly replace the use of chemical pesticides, for chemicals remain necessary in most crop situations and are still our most reliable immediate solution to such a problem. The two types of tactics are to be used together where necessary, with the chemicals being used only where really required and in ways to supplement the use of biological controls in the broad sense.