洋葱根腐病在育苗初期的空间分布型及抽样技术

李平

摘要：采用空间分布型检验、聚集强度指标检验和线形回归方法研究了洋葱生长初期洋葱根腐病在育苗田间的分布规律及其抽样技术。结果表明：洋葱2～3叶1心期洋葱根腐病株的空间分布型呈聚集分布，聚集分布受栽培环境的影响较大。建立了洋葱育苗初期洋葱根腐病株的最适抽样模型。

关键词：洋葱;根腐病;空间分布型;理论抽样模型

中图分类号：S436.33     文献标志码：A      文章编号：1001-1463（2021）05-0026-04

doi：10.3969/j.issn.1001-1463.2021.05.007

Detection of Carrying Rate of Alternaria brassicicola of Orychophragmus violaceus seed and Toxicity

Measurement of Six Fungicides on Bacteria

WANG Chunming 1， YUAN Weiwei 2， GUO Cheng 1， ZHOU Tianwang 1， JIN Shenlin 1

（1. Institute of Plant Protection， Gansu Academy of Agricultural Sciences， Lanzhou Gansu 730070， China; 2. College of Plant Protection， Funjian Agriculture and Forestry University， Fuzhou  Fujian 350002， China）

Abstract：The carrying rate of Alternaria brassicicola of Orychophragmus violaceus seed and toxicity measurement of 6 fungicides on the bacteria were determined. The results showed that separation ratio of Alternaria brassicicola was 31.3%in Orychophragmus violaceus seeds. Meantime toxicity measurement results showed that 98% Fludioxonil good bactericidal effect on Alternaria brassicicola of Orychophragmus violaceus，and the EC50 values was 0.091 2 μg/mL. The higher toxicity were 97% Iprodione， 95%Tebuconazole and 95% Pyraclostrobin， and the EC50 values were 0.197 4 μg/mL， 0.373 3 μg/mL and 0.609 9 μg/mL， respectively. The lowest toxicity were 98% Azoxystrobin and 98% Carbendazim， and the EC50 values were 146.855 1 μg/mL and 134.495 4 μg/mL， respectively. In conclusion， Alternaria brassicicola of Orychophragmus violaceus had the possibility of seed dispersal harm， and 98% Fludioxonil had best virulence to Alternaria brassicicola of Orychophragmus violaceus， then 97% Iprodione， 95% Tebuconazole and 95% Pyraclostrobin.

Key words：Leaf spot of Alternaria.brassicicola; Orychophragmus violaceus; Fungicide; Pathogenic bacteria; Inhibition rate; Toxicity measurement

甘肅河西灌区是北方洋葱主要的育苗和栽培区之一[1 ]，洋葱产业是区域特色产业之一[2 - 3 ]。近年来，在金武地区洋葱生产中调查发现，洋葱根腐病成了甘肃洋葱产业最大的制约因素，是亟待解决的难题之一。目前洋葱根腐病田间预测预报技术鲜有报道，尤其是对洋葱育苗初期田间根腐病分布规律的研究较少[4 - 6 ]。为进一步提高洋葱根腐病的预测预报与控制水平，武威市农业技术推广中心科技人员调查研究了洋葱根腐病在育苗田间的分布规律及其抽样方法，现报道如下。

1   材料与方法

1.1   调查地点和方法

调查地点为甘肃省武威市凉州区吴家井乡四方墩村。当地平均海拔1 669 m，土壤类型薄层荒漠土，年均降水量161 mm，年平均气温7.7 ℃。指示洋葱品种为红诩，密度375 000株/hm2，洋葱育苗日光温室面积420 m2。于2021年2月16 — 17日于洋葱2～3叶1心期进行田间调查。随机调查7座日光温室，每座日光温室为1个样本田块。每个样本田块均按棋盘式横向选择5个点，纵向选择10个点，每点为1个样方，每个样方面积0.25 m2，每块田调查50个样方，统计洋葱根腐病株发生数量，制作χ2频次表。……