Herbicide-resistant weed biotypes will become increasingly prevalent in plantations where herbicides are used routinely.
Resistant biotypes are often less vigorous or fit than susceptible biotypes where no herbicides are used.
Where herbicides are applied, particularly those that persist in the soil, susceptible biotypes are killed and the less fit resistant ones build up rapidly in the absence of competition.
The development of resistant biotypes could be retarded by easing the selection pressure through reducing the use of herbicides.
The more vigorous, susceptible biotypes would then suppress the less fit resistant ones.
However few growers in Western Europe could return to a situation where weeds are controlled by cultivation alone.
Rotation delays the development of resistance.
With perennial fruits, where crop rotation is impossible, rotation of herbicides is imperative using chemicals with different mechanisms of action.
Where some hand labour is available to supplement the use of herbicides, the development of resistant biotypes could be prevented by a policy of zero tolerance for weeds, i.e. by killing weeds before they are able to reproduce themselves.
Resistant weeds increase management costs.
Although expensive in the short term, a policy of zero tolerance for weeds could well be economic in some situations if assessed over a period of years.