Inner Mongolia Ordos Identification And Control Technique Of Ditylenchus Destructor On Potato

Rot stem nematode（Ditylenchusdestructor Thorne,1945）,also called the potato rot stem nematode,is important plant pathogen nematodes in the world,and is listed as a quarantine pest.In Shandong,Anhui,Henan,Jiangsu and other places,the damage of potato rot stem nematode increased year by year and posed a threat to our potato industry with the frequent transport of seed potato and the spread of agricultural machinery and manure.At present,this nematode is distributed in many provinces and cities in our country.Potato rot stem nematode disease in the potato mature stage,generally will lead to potato yield 20%～50%,serious up to 80%,or even no production.In this thesis,potato stem rot nematode disease in Ordos City was investigated.After sampling and separating nematode,morphological study was carried out under a fluorescence microscope.1.The pathogenicity of nematodes isolated from Ordos samples was verified by Koch’s rule.After 40 days of inoculation,the incidence of potato blocks was similar to that of natural potato blocks.Morphological and molecular biological tests were performed on the isolated nematodes,and the results showed that pathogenic nematodes consistent with the original inoculated nematodes were obtained.2.The indoor resistance of 22 potato varieties to potato rot stem nematode disease was identified.According to the disease degree of potato tuber,resistance evaluation was carried out,and eight varieties were resistant,namely Xiaboti,Houqihong,228,Hucinda,VT2,Xufeng No.2,Agria and Spunta.There were three susceptible varieties,namely Chuanyin No.2,Xingjia No.2 and Sifant.The field selection of 10 main varieties in Inner Mongolia showed that there was one disease-resistant variety,Qingpotato 9.A total of 1infected variety,Netherlands No.15.3.The toxicity test results in the laboratory showed that 10%phosphine thiazole granules（Longduoxi）had the highest toxicity to adult and larva of potato stem rot nematode,with LC₅₀ of 2.201mg/L and 2.182mg/L,respectively,at 100X concentration for72h.The LC₅₀ values of 10%phosphine thiazole granules（Fuqidol）and 41.7%flurimide suspension were 2.441mg/L and 2.388mg/L for adults and 2.999mg/L and 2.952mg/L for larvae,respectively.The three kinds of microecologics showed the worst effects against repeated crop,the broad-spectrum microecologics,the powdery microecologics and the liquid Bacillus TB918,and the corrected mortality rates of adult and larva were 0.Field experiment results showed that the best control effect of Avedrine thiazole aqueous emulsion and 10%phosphine thiazole granules was 89.49%and 85.74%.4.In this study,the indoor contact activity of two chemical agents and three microbial agents against stem rot nematodes was compared under different concentrations.The results showed that 41.7%fluopyramide suspension mixed with two kinds of microecological preparations had certain nematode killing effect.The corrected death rate was 58.33%at 100X concentration for 72h.For larvae,41.7%fluopyriformin suspension+anti-crop microecology preparation and 41.7%fluopyriformin suspension+Defenseworm microecologypreparation showed good toxicity against potato stem rot nematode,and the corrected death rate was more than 90%at 100X concentration for 72h.