The objective of this work was to study the interaction between three systemic fungicides belonging to triazole group and three mechanical applicator types of sprayer, i. 9. high volume (HV), low volume (LV) and ultra low volume (ULV) in controlling wheat powdery mildew. This study was carried out at Gemmeiza Research station during two growing seasons (2004-2005). The fungicides eminent (Tetraconazole)and sumi-8(Diniconazole) gave the highest values of efficacy % in controlling the disease with either of L.V. or H.V.(93.75 a 96.25 % and 87.75 & 93.75 %) and (39.53 8: 93.75 % and 85.42 a 93.75 %) sprayers in 2004-2005, respectively. While, the fungicide tilt (Propiconazole) showed the lowest values in this respect with all sprayer types. Good and significant interactions were found between the fungicides and the type of sprayer. The sprayers L.V. and H.V. gave the lowest mean of disease severity (10.55, 6.54 % and 13.33, 10.00 %) respectively in the years 2004-2005. While ULV sprayer showed the highest mean of disease severity (53.33 and 51.66 %) Technical laboratcry tests indicated that the ULV applicator produced very small droplets (196 droplets per cm: of 92 pm in diameter). The LV applicator produced small spray droplets (144 droplets per cm2 of 174 pm in diameter), while the HV applicator produced relatively large spray droplets (59 droplets per cm2 of 213 pm in diameter). Spray using HV applicator depend on the pressure of the handle pump. Also, the LV applicator works using air pressure with air velocity about 43.7 mfsec. The two sprayers produced large droplets compared with the ULV sprayer. Droplets of HV and LV interfuse the heavy growth plants with drag force by pressure and air velocity respectively. Meanwhile, spray using ULV applicator which works with centrifugal force produced very small fine droplets that have low speed. Therefore, it's ability to interfuse the heavy growth plants will not occur. These results put spot light on the importance of choice the type of sprayer to the kind of the crop plant. The plants has heavy growth i.e. wheat (300-350 tillerr'mz) must be sprayed with sprayer has drag force of droplets while the crops has vast leaves i.e. cucurbitaceae must be sprayed with ULV sprayer for controlling plant diseases.