Level of threshold weed density does not affect the long-term frequency . . . It is shown that long-term application of thresholds results in a control frequency that is independent of threshold level, and in aperiodic dynamics of the weed population which may cause uncertainty about what control frequency and hence what costs of control are expected over a given period
Weed control thresholds: a useful concept in natural ecosystems? However, because most weed populations generate effects that carry over to following years, an eco-nomically-defined action threshold that deals solely with impact in the current sea-son is not suited to triggering action on weed control
Weed control thresholds: a useful concept in natural ecosystems? The threshold concept has received considerable attention in relation to the management of well-established weeds and other pests in agricultural systems, but its applicability to the management of weeds of natural ecosystems has yet to be examined in any depth
Impact of Environmental Weeds on Biodiversity Where an environmental weed has reached its biogeographical limits with extensive "infilling", it can be difficult to find suitable control sites where the weed is absent or at low densities
Weed Thresholds: The Space Component and Considerations for . . . - JSTOR As an extension of weed threshold models in which crop losses are based on weed density, an altemative model for grass weeds in cereal crops is proposed that incorporates the theoretical importance of selection for herbicide resistance, initial weed population frequency, and weed seed dispersal