| Wheat cyst nematode disease is an important nematode disease on wheat production in the world.The disease causes great losses in the world,causing economic losses of about 78 billion US dollars a year,affecting the safety of food crop production.At present,wheat cyst nematode has been found in 16 provinces and cities in China.The main pathogen is Heterodera avenae and some areas are Heterodera filipjvei.There are many studies on H.avenae,but there are few studies on H.filipjvei with stronger infection ability.In this paper,based on the investigation of the occurrence of wheat cyst nematode,the infection dynamics of H.filipjevi,the evaluation of wheat germplasm resources resistant to H.filipjevi and the demonstration of Heterodera filipjvei chemical control were studied.The results are as follows:1.It was found that wheat cyst nematode occurred in Longdong area of Gansu Province,Guanzhong area of Shaanxi Province,Hebei Province and Henan Province,and there were significant differences in field cyst density in different areas.The incidence of wheat cyst nematode in Kongtong District and Lingtai County was the most serious in Longdong area of Gansu Province,with an average of 13.4 and 11.8 cysts per 100 mL soil samples,while that in Heshui County was the least,with an average of 3.9 cysts per 100 mL soil samples.In Guanzhong area of Shaanxi Province,the average number of cysts per 100 mL soil samples was 19.1 in Xinglin Town,Fufeng County,and 0.2,0.4 and 0.5 per 100 mL soil samples in Yinjiawu Township,Liulin Town and Chencun Town,Fengxiang County,respectively.In Hebei Province,the incidence of wheat cyst nematode was the most serious in Daming County,Handan City.The average number of cysts per 100 mL soil samples was 36.9.The incidence of wheat cyst nematode in Shijiazhuang Mayor'an District was the lightest when the number of individual soil samples was more than 50 / 100 mL;.The average number of cysts per 100 mL was 6.3.The results showed that the incidence of wheat cyst nematode was the lowest in Daming County,Handan City.In Henan Province,the most serious occurrence was in Nanle County,Puyang City,where the average number of cysts per 100 mL soil samples was 51.7,and that of the most serious soil samples was 129 per 100 mL soil samples,while that in Yicheng District of Zhumadian City,where the occurrence degree was the lightest,was only 1.7 per 100 mL soil samples.2.Through fixed-point sampling and continuous observation of wheat field in Xuchang,Henan Province,it was found that the second instar larvae of Heterodera filipjevi invaded the roots of host plants 30 days after sowing(November 9),and reached the first infection peak 40 days after sowing(November 22).No active nematodes were detected in the soil 80 days after wheat sowing(January 3).The infection of the second instar larvae was detected in the roots 140 days after wheat sowing(March 8),and about 160 days(March 28).The second instar larvae reached the second infection peak and a large number of third instar larvae(March 28)and fourth instar larvae(April 8)were observed,and white females formed and began to fall off in the middle and last ten days of April.On May 27,wheat entered the harvest period,and a large number of brown cysts were detected in the soil.3.In this paper,the resistance of wheat germplasm resources to Heterodera filipjevi was evaluated by field nursery method.The resistance evaluation was a synthesis of Andersen's,Nicol's and Soriano's.The results showed that there were 4 wheat resources with disease resistance(R)in the field,which were CA12022,2018J1 Jing 411,2018C5 Iris and 2018B4 EraZ.Among them,the number of white females per plant of 2018J1 Jing411 and 2018C5 Iris were 1.6and 3.6respectively,which showed high resistance(HR)under the evaluation of Andersen.CA12022 and 2018B4 EraZ only moderate resistance(MR)under the evaluation of Andersen.4.A field experiment on the control effect of was Heterodera filipjevi carried out from 2018 to 2019.The results showed that seed coating agents such as Xiangnong(1:35),Gannong 1(1:35)and Gannong 3(1:35)had control effect on Heterodera filipjevi.The control effects were 44.75%,34.92% and 32.49%,respectively.Xiangnong(1:35)had significant difference in control effect,but the effect of increasing wheat yield was not obvious.Avermectin(1:40)seed coating treatment had low control effect,but the wheat yield increased significantly,and the yield increased by 24.34%.The experimental results of adjusting sowing date showed that the control effect of late sowing for one week on wheat was 15.29%,and the yield increase was 14.07%,and the difference was not significant,but the control effect of seed coating treatment for one week of late sowing was-14.18%,and the yield increase was only 6.06%. |
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