摘要
比较种子带菌和土壤带菌作为接种体来源的田间试验,结果证明,土壤带菌是田间接种体的主要来源。不同带病水平的种子,即使100%带病,引起病害的严重度没有多大差别,在发病初期调查,连作地的平均病指为2.98%,而与玉米轮作的地块仅为0.98%,病害降低了67.11%。室内进行的接种条件研究证明,接种体的浓度以每毫升悬浮液中含40000个孢子为宜。接种后,应立即保湿。孢子落到叶片上,没有足够湿度的情况下,6天后便失去侵染活力。孢子在饱和湿度下,2小时亦能侵入,2～8小时侵染率都很低,以保湿24小时的效果较好。
Field tests for comparing seedborne and soilborne inoculum sources of Cercospora sojinademonstrated that the latter was the major source of inoculum in fields.Disease severitycaused by different seedbone inoculum levels,even if 100%seeds were diseased,showed nosignificant difference.The disease was more severe in fields which previously cropped withsoybeans than in those cropped with corn.During primary infection period,the average dis-ease indices were 2.98% in the continuous-soybean fields but only 0.98% in thecorn-soybean rotation fields,i.e.reduced by 67.11%.The tests of inoculation conditions in the greenhouse indicated that the most suitableconcentration of inoculative suspension was 4×10~4 spores per milliliter.The plants should bekept in moist chamber immediately after inoculation.Infectivity of the dry inoculum on leavescould be maintained for only 5 days.Infection of the inoculum occurred in 2 hours if therewas adequate moisture.The infection rate was low in 2～8 rours after inoculation.24hours'm oist period after inoculation was the most favorable for infection of inoculum.
关键词
大豆灰斑病
接种体来源
接种条件
Cercospora sojina
inoculum sources
inoculation conditions
