沉降剂控制热雾机热雾滴扩散范围及防效的研究

Application of sedimentation agent to controlling the droplet spread of thermal fogger and control effect to crop diseases

热雾机一般以柴油为热雾剂承载农药，形成的热雾喷出后随着喷口产生的动力和热雾的自身密度压差向前方自行推进，该施药技术由于效率高而广泛用于林业病虫害的防治。但由于热雾易飘移、难控制，造成农药污染的缺陷，在农作物生产中难以推广应用。本试验通过加入热雾沉降剂的方法，加大了热雾机热雾滴的比重和沉降速度，在此基础上，选择难以进入田间施药的玉米、油菜，进行了中、后期病害的防治试验，结果表明：加入热雾沉降剂后热雾滴的主体分布于田间水平距离（0~25 m）和垂直高度（0~2 m）范围内，分布密度为148.5~265.4粒/cm2，同柴油对照相比，加入热雾沉降剂后,同等直径的热雾滴飘移的距离和高度明显降低。田间防治试验结果也表明，热雾机施药对油菜菌核病和玉米南方锈病的防治效果普遍高于机动弥雾机喷雾的防治效果,加入热雾沉降剂后可提高有效防治范围内的防效。

Thermal fogger formed heat fog by means of diesel oil for dispersing pesticides. The fog moved forward along with the power in the spout and the difference of density pressure, and sprayed around the field. Since the efficiency of the spraying technique was high, it was widely used to control the forest diseases and pests. However, it was difficult to be used in crops because of the drift potential of the fog droplet. In this study, through increasing specific gravity and improving sedimentation rate by adding the sedimentation agents, the control efficiency of the technique for oilseed rape sclerotium blight and maize southern rust were tested. The results showed that the most droplet deposition was well distributed at the level distance from 0 to 25 m, or vertical height from 0 to 2 m after adding the sedimentation agents, and the droplets were about 148.5-265.4 per cm2. Under the same diameter, the drift distance and height of the thermal fog droplets dropped significantly by using sedimentation agent. The control effect of chemicals on crop diseases by thermal fogger was higher than that of electric mist sprayer. At the range of effective distance, sedimentation agents could improve the control efficiency.