| Ditylenchus destructor is an important plant pathogenic nematode and also a well-known important quarantine pest in the world,which belongs to migratory parasitic nematode in plants.This nematode can cause to the rot and deterioration of potato tubers,which is not only causes serious economic losses,but also threatens the healthy development of the potato industry.This research was conducted from four aspects including the identification and detection of D.destructor,the resistance evaluation of potato varieties,biological control and the screening of chemical agents.The main research results were as follows:1.A nematode population caused potato damage was identified as D.destructor by morphology and molecular methods.The results showed the morphological characteristics and measurements of the population and it was belonged to type B group of D.destructor.The results of pathogenicity test showed that the symptoms of the disease were basically the same as those of the natural diseased potatoes after the artificial inoculation of the nematode population,and the newly isolated nematodes were consistent with the inoculated nematodes.The results also showed that the specific primers Dd L1 and Dd L2 could be used to detect D.destructor in potato tuber tissue and soil samples directly.2.The indoor resistance of 23 potato varieties mainly planted in Inner Mongolia was identified.According to tuber disease incidence result,8 varieties showed high resistance,which were Xisen 6,Kexin 1,Qingshu 9,Longshu 3,Zhongshu 2,Yanshu 8,Jinshu 18 and Zaodabai;9 varieties were susceptible like Favorite,Atlantic,Golden,Lishu 6,Spunta,Jizhangshu5,Zhongshu3,Zhongshu13 and Zhongshu15.For nematode fecundity result,Longshu 3,Zaodabai and Xisen 6 showed high resistance;8 varieties were susceptible including Atlantic,Golden,Favorite,Lishu 6,Jizhangshu 5,Zhongshu 3,Zhongshu 13 and Zhongshu 15.The resistance levels of major potato varieties in Inner Mongolia were combined by the two evaluation methods,and Longshu 3,Zaodabai and Xisen 6 showed high resistance level.3.In this study,the strain ZWZ-19 among 156 bacteria strains showed the strongest contact and fumigation activity for D.destructor.The results of indoor pot experiment showed that the incidence rate and disease index were 31.75% and 10.75 respectively,and the control effect was reached to 59.46%.Compared with the chemical control,the difference is not significant.The results of control test in fields showed that ZWZ-19 fermentation liquid treatment can effectively control potato disease caused by D.destructor,and its incidence rate and disease index were significantly lower and the control effect reached to 51.01%～87.51% compared with the control.4.Indoor contact toxicity of five chemical and four microbial agents against D.destructor in different concentration levels,and further explore the complex effect of chemical and microbial agents on the nematode.The results showed 70% Hymexazo WP had the strongest contact toxicity with 87.56% corrected death rate,and 20% Fosthiazate EW and 41.70% Fluopyram SC followed in 72 h for recommended dose from five chemical agents.The two highest corrected death rate of Hymexazo WP and Fosthiazate EW were 84.61% and 81.68% respectively after 100 times dilution in 72 h from aboved three agents.In four microbial agents,500 g / L Anti-root-knot nematode agent DP showed strongest contact toxicity with 76.48% corrected death rate,and 66.6g / L Bacillus subtilis agent WP followed in 72 h for recommended dose.Corrected death rate rose to 85.58% after treated with 125% Anti-root-knot nematode agent DP in 72 h.Contact toxicity became stronger when treated with complex agents in incertain concentration,70% Hymexazo WP combined with Anti-root-knot nematode agent DP showed strongest contact toxicity with 93.30% corrected death rate and 20% Fosthiazate EW combined with Anti-root-knot nematode agent DP followed with 81.68% corrected death rate in 48 h. |
PDF Full Text Request