Zeitschrift für Pflanzenkrankheiten und Pflanzenschutz - Journal of Plant Diseases and Protection (1990) 97, 142-153
W. Koch and M. Kunisch (1990)
Die Unkrautproblematik in Abhängigkeit von natürlichen and geselischaftlichen Gegebenheiten
[The influence of natural and social factors on the magnitude of weed problems]
Zeitschrift für Pflanzenkrankheiten und Pflanzenschutz - Journal of Plant Diseases and Protection 97 (2), 142-153
Abstract: Weed problems are normally greater in highly disturbed agro-ecosystems (arable land) than in little disturbed ones (established permanent crops). They are greater under conditions of high water supply than in arid regions.
The areas of distribution of a plant species as a weed are smaller than those of the species as such. Often closely related species or subspecies take the place of a species beyond its area of distribution: Avena fatua is being replaced by A. sterilis in warmer regions, its subspecies ludoviciana and macrocarpa having also different areas of distribution. Temperature is of great importance in determining the area of distribution. The roles of water and photoperiod are less obvious, probably partly due to lack of experimental data.
Weed problems differ fundamentally in traditional crop production systems from those in industrialized ones, weed control normally being the main labour peak during crop development in traditional systems, except in dryland cereal production. Availability of labour during the time of weed control often limits the cropping area. The diversity and the efficiency of weed control measures are lower in traditional systems and they are more labour consuming, the labour input being highly density dependent. Critical periods are more important than threshold values in weed control strategies in traditional farming. The possible increase of weed pressure due to remaining weeds is of greater importance in traditional systems than in industrialized ones due to the density dependence of labour requirement for traditional weed control.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: German)
Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
control - general
