丙环唑和醚菌酯药液浓度、雾滴密度与其对小麦白粉病防效的关系
Effects of concentration, droplet density of propiconazole and kresoxim-methyl on the efficacy against wheat powdery mildew

采用室内生物测定和田间试验相结合的方法，研究了丙环唑和醚菌酯的药液浓度及雾滴密度与其对小麦白粉病防效的关系，首次提出了杀菌剂雾滴抑制中密度（即达到50%抑制率时所对应的雾滴密度，EN50）这一概念。结果表明：1）室内喷施丙环唑及醚菌酯药液，当丙环唑质量浓度从0.01 g/L提高到1.0 g/L时，对应的EN50值从18.7 cm–2下降至5.1 cm–2，EN90值从755.8 cm–2下降至92.8 cm–2，雾滴杀伤半径（r50）从0.92 mm增大到1.77 mm；当醚菌酯质量浓度从0.01 g/L提高到1.0 g/L时，对应的EN50值从227.1 cm–2下降至1.0 cm–2，EN90值从596.1 cm–2下降至26.9 cm–2，雾滴杀伤半径从0.27 mm增大到4.00 mm。2）田间使用MG-1S植保人机和背负式电动喷雾器喷施丙环唑和醚菌酯防治小麦白粉病，人机施药液量为15.0 L/hm2，药液质量浓度为5.0 g/L时，在小麦旗叶及倒二叶的雾滴密度分别为29.7和9.5 cm–2，喷施丙环唑和醚菌酯3、5、7 d后，对小麦白粉病的防效分别为41.9%、80.7%、90.2%和30.8%、67.9%、84.5%；电动喷雾器施药液量为450.0 L/hm2，药液质量浓度为0.17 g/L时，在小麦旗叶及倒二叶的雾滴密度分别为287.9和204.2 cm–2，喷施丙环唑和醚菌酯3、5、7 d后的防效分别为42.1%、85.3%、94.3%和28.5%、80.1%、90.5%。研究表明，田间施用丙环唑和醚菌酯时，需把叶片全部喷湿，只需达到一定雾滴密度即可；运用植保人机进行高浓度、低容量喷雾时，10~30 cm–2雾滴量即可达到理想的防治效果。
The effects of concentration, droplet density of propiconazole and kresoxim-methyl on the control efficacy against wheat powdery mildew were investigated using a combination of indoor bioassay and field experiments. In this study, a new concept, inhibited medium density (EN50) was defined as the density of droplet that achieve 50% inhibition rate. The results showed that:1) In terms of the indoor propiconazole spraying tests, with the spraying concentration increased from 0.01 g/L to 1.0 g/L,the corresponding EN50 value decreased from 18.7 cm-2 to 5.1 cm-2, the EN90 value decreased from 755.8 cm-2 to 92.8 cm-2, and the biocide radius increased from 0.92 mm to 1.77 mm. With regards to indoor kresoxim-methyl spraying tests, when the spraying concentration increased from 0.01 g/L to 1.0 g/L, the corresponding EN50 value decreased from 227.1 cm-2 to 1.0 cm-2, the EN90 value decreased from 596.1 cm-2 to 26.9 cm-2, and the biocide radius increased from 0.27 mm to 4.00 mm. 2) The field spraying test of propiconazole and kresoxim-methyl against wheat powdery mildew were conducted using MG-1S UAV(unmanned aerial vehicle) and knapsack sprayer. When tested with the spray volume of 15.0 L/hm2 for UAV at the concentration of 5.0 g/L, the droplet density on flag and 2nd top leaf was 29.7 cm-2 and 9.5 cm-2, respectively. After 3 d, 5 d and 7 d, the control efficacy was 41.9%, 80.7%, 90.2% for propiconazole, respectively, and 30.8%, 67.9%, 84.5% for kresoxim-methyl, respectively. When tested with the spray volume of 450.0 L/hm2 for knapsack sprayer at the concentration of 0.17 g/L, the droplet density on flag and 2nd top leaf was 287.9 cm-2 and 204.2 cm-2, respectively. After 3 d, 5 d and 7 d, the control efficacy was 42.1%, 85.3%, 94.3% for propiconazole, respectively, and 28.5%, 80.1%, 90.5% for kresoxim-methyl, respectively.