关于我国水稻白叶枯病杂草传病研究的进展

 本文报导了云南,浙江,安徽,江苏四省水稻白叶病杂草传病情况,试验结果证明有双穗雀稗Paspalum distichum,稗 Echinochloa crus-galli,茭白Zizania caduci-flora,马唐Digitaria sanguinalis,车前Plantago major,芦苇 Phragmites communis,狗牙根Cynodon dactylon,紫云英Astragalus sinicus,假稻Leersia japonica等十余种杂草不仅带菌,还可在根围 Rhizosphere增殖,存活到次年5—6月,以其浓缩液接种在水稻健苗上,均能产生白叶枯病典型症状。杂草带菌传病可分为两个类型,一类是如日本的秕谷草Leersia sayanuka,和中国的茭白Zizania caduciflora,是属于稻白叶枯病的中间寄主,另一类如双穗、雀稗,马唐是属于非寄主植物的杂草,它并不表现症状也不能接种,但病原细菌均可借其根茎部的根围增殖,存活而传病。用越冬带菌杂草与健苗混栽在花钵或水泥池内,或进行水泥池淹苗接种试验以及大田除草验证,都证实带菌杂草可感染健苗引起发病。根据杂草带菌传病的事实,绘制了新的侵染循环图。

Advance Concerning the Studies on Weed Carriers of Bacterial Leaf Blight of Rice in China

This paper reports the present spread of bacterial leaf blight of rice by weed carriers from four prorinces covering Yunnan,Zhejiang,Anhui and Jiangsu. Experiment confirmed that a variety of weeds,including paspalum,Eehino-ehloa erus-galli,Zizania cadueiflora,Digitaria sanguinalis,Plantago major, Phragmites eommunis,Cynodon daetylon,Astragalus sinicus,Leersia japonica and up to 10 more weed speeies,not only served as bacterial carriers,but also could afford bacterial multiplication their rhizosphere and survived till May to June of the next year.Inoculation by concentrated bacterial liquid culture on healthy rice seedlings showed typical symptoms of bacterial leaf blight.The mode of disease spread by weeds can be divided into two kinds.One is that weeds eadueiflora of China served as alternate hosts such as leersia sayanuka of Japan and Zizania and the other one is that weeds such as paspalum disti-chum,Digitaria sanguinalis is known as nonhost plants which showed no symptoms in nature and also failed to show any symptom by artificial inocu-lations,However,the pathogenic bacteria could survive and multiply the weeds rhizospheres and caused disease spread. Using bacterial carriers weeds grown together with healthy rice seedlings in pods or in cement plots or applying drench-inoculation in cement plot as well as the eradication of weeds in.field all confirmed that the pathogenic bacteria from weed carriers could infect healthy rice seedlings and induce disease. A new disease cycle was drawn based on the fact that pathogenic bacteria were carried by weeds and spread disease.