特谱唑防治小麦锈病毒理与应用技术的初步研究

据室内测定结果,特谱唑具有很强的内吸传导性能,用灌土法施药的效果可与叶面喷雾法相比拟,但基本上是向上传导。此药具有很强的治疗和铲除作用,在病菌潜育期施药,可控制到不发病,最多只显退绿斑;在退绿期施药,可使病菌夏孢子堆变成褐色小点,孢子粉极少,但对夏孢子的萌发影响则弱。此药剂比三唑酮毒力强,其毒力指数(三唑酮为100)都在900以上,即达到 EC_(50)和 EC_(95)所需的剂量,前者只需后者的11%以下,特别是保护作用突出。据田间试验结果,此药剂的用药量比三唑酮少,如控制条锈病为害所需的剂量只要三唑酮的三分之一。防治条锈病的用药量一般以45—47g/ha(有效成分)为合适;用药期以病叶率5%—10%、小麦处于旗叶伸长期为宜;施药次数以上述的合适剂量和适期喷施1次即可控制整个成株期条锈病为害,收到最佳的经济效益。

PRELIMINARY STUDIES ON THE TOXICITY AND APPLICATION OF DINICONAZOLE FOR CONTROLLING WHEAT RUST

Diniconazole has been prover to be an ideal fungicide for control ofwheat rust with following characteristics:low applying dosage,higheffective and longer-term persistence than Triadimefon that widely usedin China at present.The results of experiments in the green house indicated that Dini-conazole possessed good absorbability and upward conductivity in plants,The effect in pouring soil with it was similar to the foliar spraying.At the same time,Diniconazole showed a strong function of cure anderadication in controlling wheat rust.When applying it in latent periodof Puccinia striiformis,on wheat leaves didn't appear uredia,only oc-casionally chlorotic spots.When applying it in the period of chloriticspots,uredia of Puccinia striiformis and P.recondita became very smallbrown spots which consisted of a few urediospores,and their germina-tion ability was obviously suppressed.The toxicity index of Dinicona-zole to wheat rust was over 900 which was 10 times more than Triadi-mefon's.Its dosage for EC_(50) and EC_(95) equaled 11 percent of Triadime-fon's.According to the field trials,the dosage for controlling wheat yellowrust was 45-75g(a.i.)/ha which is equalto one-third of Triadimefon's.The suitable time of application was the period of 5 to 10 percent ofthe leaf-rusted,which occured at the stage of flag leaf extending.Spraying just one time with the dosage and at period above-mentioned,the best economic effect could be obtained.