丙硫磷控制稻瘟病的作用方式及应用技术

经１９９３－１９９５年生物测定和田间多点试验示范发现；１．丙硫磷对稻瘟菌孢子萌发和附着胞形成有显著的抑制活性，ＥＣ５０为１０３．３ｍｈ／Ｌ，５００ｍｇ／Ｌ的抑菌率达９６．２％；２．丙硫磷１０００ｍｇ／Ｌ对水稻苗叶瘟和穗瘟的预防效果分别为７９．４％和９０．７％，治疗效果分别为３９．３％和４１．８％；３丙硫磷６００－９００ｇ／ｈｍ＾２防治双季稻和瓜后稻穗瘟病的田间小区效果分别为７０．８％－８０．２％和

ACTIVITY,MODE AND APPLICATION OF PROTHIOFOS AGAINST RICE BLAST

Bioassay,field tests and extension of prothiofos against rice blast were progressively conducted in multi-locations from 1993 to 1995.It was discovered that (1) prothiofos was effective as an inhibitant of Pyricularia oryzae from its appressorial function,with EC₅₀ of 103.3 mg/L and 96.2% inhibition at 500 mg/L;(2) preventive efficacy of prothiofos at 1000 mg/L was 79.4% for control of rice shoot blast and 90.7% for control of panicle blast,while curing efficacy was 39.3% and 41.8%,respectively;(3) efficacy of the pesticide at 600-900 grams (ai) per hectare was 70.8%-80.2% against the panicle blast in paddies of the earlier rice of double crops a year,or 71.1%-77.2% in paddies of the latest rice of triple crops a year;(4) average extension efficacy of prothiofos at 750-900 grams per hectare sprayed at initial emergence of rice panicles was 62.5%-70.2% for control of the panicle blast and 96.9%-97.4% for concurrent control of white-heads damaged by yellow stem borer (YSB) in the same paddies of multi-locations,each of which was significantly higher than that of treatment with both of t.ricyclazole and dimehypo (55.6% for control of the blast and 91.0% for YSB).