影响四川凉山地区烟草根结线虫病发生的关键气候因子分析

Exploring the Key Climatic Factors Driving the Outbreak of Tobacco Root-Knot Nematodes in Southwest China

烟草根结线虫病是一种由根结线虫(Meloidogyne spp.)侵染引起的重要土传病害,目前,对于影响烟草根结线虫病发生的关键因子研究相对缺乏,其监测预警和防治难度依然较大,该病的灾变机理有待进一步探索.本研究通过田间调查和室内分析相结合的方法,明确了2020年四川省凉山州主要植烟区烟草根结线虫病发生面积和为害程度,其中,以四川省会理市通安镇发病最为严重,发生面超过52%,发病烟田的烟株感病率超过46%,死棵率超过34%.同时,借助形态学鉴定的方法明确了从越西县、盐源县、德昌县、宁南县、会理市和会东县采集到的烟草根结线虫种类均为南方根结线虫(Meloidogyne incognita).进一步对会理市2010—2020年同期历史旬平均气温和旬降雨量的对比分析结果表明,烟草根结线虫发生严重的会理通安镇,1—4月平均气温均高于同期历史值,温度差为0.7~5.0℃,平均高出2.8℃,2020年1-4月的累计降雨量较历史值高15%以上,5—8月的累计降雨量较历史值低40%以上,研究结果表明,烟苗移栽前较高的温度和较多的降雨以及移栽后较少的降雨是凉山州烟草根结线虫病严重发生的重要诱因.本研究结果也为烟草根结线虫病的监测预警和及时有效防控提供了参考.

Tobacco root-knot nematode is an important soil-borne disease caused by Meloidogyne spp.,which is distributed in major tobacco-growing areas in China,and can cause 30%~50%of yield loss in severe cases.Even more,the severity of root-knot nematode is increasing year by year.At present,there is relatively little research on the key factors affecting the occurrence of tobacco root-knot nematode disease,and the disaster mechanism of the disease needs further exploration.By combining field investigation and laboratory analysis,this study determined the occurrence area and damage degree of tobacco root knot nematode disease in major tobacco-growing areas of Liangshan Prefecture,Sichuan Province in 2020.By morphological identification,Meloidogyne incognita was identified as the root knot nematode of tobacco collected from Liangshan Prefecture.Further comparative analysis of the average temperature and rainfall during 2010—2020 in Huili City showed that the average temperature from January to April in Tongan area,where tobacco root-knot nematodes occurred seriously,was higher than the historical value of the same period,with a temperature difference of 0.7~5.0℃,which was 2.8℃higher on average.The cumulative rainfall from January to April in 2020 was more than 15%higher than the historical value,and the cumulative rainfall from May to August was more than 40%lower than the historical value.The results showed that higher temperature and more rainfall before tobacco transplanting and less rainfall after transplanting were important effectors of the serious occurrence of tobacco root-node nematode disease in Liangshan Prefecture.The results of this study provide a reference for monitoring and warning as well as timely prevention of root knot nematode disease.