Increasing costs in the agricultural sectors is nowadays with the use of herbicides on weeds control that need to use non chemical methods to reduce the environmental impact of chemical herbicide, insecticides and weedicide to prevent weed resistance, use of allelochemical natural herbicide for weed control to reduce the costs. In integrated weed management programs allelopathic chemicals as an alternative for weeds control. These chemicals inhibit the weeds growth and as a weapon to be used against these unwanted plants. Allelopathic crops species relationship, genetic diversity is very extreme and genetic control of these compounds to be seems. The main aims of this review paper are to find out the efficient allelopathic nonchemical control method of weeds from crops and best way of controlling the noxious weeds with these plants extracts.

Keywords: allelopathic, chemicals, crops, weeds.