Compounds that are promising under the controlled conditions of laboratory testing may be disappointing in the field because insufficient of the applied active ingredient reaches the ultimate biological target. Herbicide targets are the soil and weed foliage. Leaves often repel spray droplets leading to bouncing or running off and herbicide that reaches the soil may be lost by evaporation, photodecomposition, adsorption or breakdown before being taken up by weed roots (Chapter 6). Losses also occur by detoxification within the plant so that ultimately a small fraction only of the original dose is physiologically active in killing weeds. This loss of expensive chemical between sprayer and site of action is common to other pesticides and an aim of current research is to reduce the consequent wastage, environmental contamination and damage to non-target organisms that results. The initial choice of herbicide and formulation, mode and timing of application, prevailing weather and other factors, all may influence the proportion of herbicide reaching the target and the effect it has when it gets there. For example, quite small differences in the droplet size spectrum, concentration of wetting agent or other adjuvant, or in air temperature or relative humidity before, during or after spraying, can all have profound effects on the retention of herbicide on leaves and subsequent uptake, movement and behaviour within the plant (Chapter 6).
Unable to display preview. Download preview PDF.
- ANON (1978). Poisonous Chemicals on the Farm, HMSO, London, p. 38Google Scholar
- BALS, E. J. (1975). Development of a CDA herbicide handsprayer, PANS, 21, 345–349Google Scholar
- COFFEE, R. A. (1980). Electrodynamic spraying, Spraying Systems for the 1980’s, Monograph 24, British Crop Protection Council, London, p. 317Google Scholar
- FRYER, J. D. and MAKEPEACE, R. J. (eds.) (1977). Weed Control Handbook, Vol. 1, Principles, Blackwell, OxfordGoogle Scholar
- LINKE, W. (1978). CDA — a review of developments to date, Proceedings 1978 British Crop Protection Conference — Weeds, pp. 1047–1057Google Scholar
- MAFF (1979). Horticultural Sprayers for Small Areas, booklet 2070, Ministry of Agriculture, Fisheries and Food, London, p. 21Google Scholar
- MAFF (1980). Approved Products for Farmers and Growers, Ministry of Agriculture, Fisheries and Food, London, p. 330Google Scholar
- MATTHEWS, G. A. (1979). Pesticide Application Methods, Longman, London, p. 334Google Scholar
- TOTTMAN, D. R. (1976). Spray timing and the identification of cereal growth stages, Proceedings 7976 British Crop Protection Conference — Weeds, pp. 791–800Google Scholar
- GROENWOLD, B. E., PEREIRO, F., PURNELL, T.J. and SCHER, H. B. (1980). Microencapsulated thiocarbamate herbicides: A review of their physical, chemical and biological properties, Proceedings 1980 British Crop Protection Conference — Weeds, pp. 185–191Google Scholar
- OUTLOOK ON AGRICULTURE, 10 (7) (1981). This issue is devoted entirely to spray application technology.Google Scholar
- PROCEEDINGS OF Symposium on Controlled Drop Application (1978). Monograph 22, British Crop Protection Council, London, p. 275Google Scholar
- WALKER, J. O. (1980). Spraying Systems for the 1980’s, Monograph 24, British Crop Protection Council, London, p. 317Google Scholar