【摘要】 防治双季晚稻矮缩病,采用连片种植,改进耕作栽培方法,选用抗(耐)病品种等农业技术措施,再在本田初期及时治虫1—3次,能达到80%以上的防病效果。不用农业防治,单在本田初期及时治虫1—3次防治效果为59.6%。但对小面积晚稻,在本田初期于介体昆虫迁飞高峰期及时治虫2—4次,防病效果也能达到80%以上。欲使晚稻后期的株发病率分别控制在1%、3%和5%以下,其本田初期防病治虫的指标是:当介体昆虫的带毒率为2.5%时,分别为每百株苗虫量4、12和22头;而当介体昆虫的带毒率为5%时,分别为每百株苗虫量2、6和10头。更多还原

【Abstract】 The rice dwarf disease of the second crop of rice transmitted byleaf-hoppers was to be reduced over 80% by the following measures:adopting resistant(or tolerant)rice cultivars,improving cultulral prac-tices,growing the rice cultivars of about the same growth duration inthe adjacent stretches of fields and applying insecticide for 1-3times atthe initial stage of plant growth in transplanted fields.Without adop-ting agricultural measures and merely applying insecticides 1-3 timesfor the second crop of rice,less than 59% of control resulted.In smallareas of rice fields,only 2-4 applications in time of the peak stage ofinsect vectors migration resulted in more than 80% of control.If it isexpected to control the incidence of dwarf disease in the second cropof rice down to 1%,3% and 5% the number of leaf-hoppers per plantused as criterion for insecticide application was 4,12 and 20 respec-tively when the viruliferous rate of vectors was 2.5%.When the viruliferous rate of vectors was 5%,the number of leaf-hoppers per plant used as criterion for insecticide application was 2,6,and 10 respectively.更多还原