Scientists at the Bonn Institute of Plant Cultivation, University of Bonn, have developed a herbicide sprayer that identifies weeds while moving across the ground and is able to pinpoint which weeds it needs to attack. Field trials demonstrate a saving of 50% of the herbicides normally used. The sprayer is to be manufactured by the Norwegian Company, Kverneland. Every year farmers can spend up to Euro 200 per hectare to control weeds which adds up to a lot of money quite apart from the environmental impact.  Three digital cameras which photograph the ground while crossing it are at the heart of this high-tech sprayer. Images are sent to a computer that extracts the contours of the plants and a second computer compares the pictures which samples in a data bank. Some herbicides are effective only against grasses and others only against dicoltyledonous plants. The new sprayer will be able to select the most effective herbicide against a given weed from a given series of 3 herbicides carried by the sprayer at any one time. The computer is also able to decide the most effective dose rate. Where no weeds are growing, nothing is sprayed. The sprayer can move over the ground at up to 10km/hour with each of the cameras taking two photographs per second.  AG. For further information contact Dr. Roland Gerhards: E-mail: r.gerhards@uni-bonn.de  Pictures from www.uni-bonn.de