Using the flame in weed control is the most important alternative that means least harmful to environment and alternative to use of herbicides. Therefore, the main aim of this study was investigating the possibility using diesel fuel in weed control by developing and modifying the air-blast sprayers that it was investigated to killed and removed weeds in and aside irrigation and drainage filed ditches and also around fruit trees. This is done by installing a unit to generate the flame at the end of the air exit hole with replacing the pesticide inside the tank with diesel fuel. The experiments were conducted at the El-Serw Agricultural Research Station in 2013. The theoretical study was identified to determine the appropriate burning rate to singe, intensity and effect of flame out distance from device. The fuel diesel amount, fuel consumption and field capacity were estimated under flame speed of 1.6, 2.0 and 2.4 km/h; air velocity of 44, 57, 68 and 83 m/s and nozzles diameters of 0.75, 1.00 and 1.25 mm. The modified flame device evaluated measuring the flame length, completely flamed weeds ratio per m². The fuel diesel for weeds controlling was estimated and fuel consumed and then the field capacity. The results indicated that using the modified flame device to burn weeds in and aside irrigation and drainage filed channels at the operating forward speed of 1.6 km/h, and air-blast speed of 83 m/s with nozzle diameter of 1.0 mm achieved a long effective flame length of 92 cm, weeds burning rate, directly after treatments, of 95 % and burning weeds rate 8 hours later, of 100 %. Field capacity was 1407 m²/h and diesel consumed for flaming 5.5 l/1000m² under the same previous conditions respectively. The study recommended that using the developed device in and aside irrigation and drainage filed channels and around fruit trees. Furthermore, it can be used in small holdings with possibility of developing the device to become self-propelled for use in large spaces.