Occurrence Of Cereal Cyst Nematode On Wheat In Nine Provinces Of China And Its Intergrated Control

Cereal cyst nematode(CCN)is an important group of plant parasitic nematodes in the world,which causes great damage to cereal crops,including wheat,barley,rye,oats and pasture.It has been widely distributed in more than 40 countries and up to now been spread to 16 provinces in China.The systematic survey of CCN occurrence in main wheat growing areas in nine provinces of China was carried out and the intergrated control including seeds-coating chemicals,biocontrol agent and avermectin granular were studied in order to support the effective control of CCN and provide security for food production in China.During May 2014 and May 2015,a systematic field survey was carried out for occurrence of CCN on wheat-growing areas from 68 counties in 27 districts of Jiangsu,Henan,Shandong,Anhui,Hebei,Shanxi,Shaanxi,Gansu and Qinghai Province.Total 233 samples with roots and soils were collected from wheat field.The results revealed that CCN occurred unevenly in wheat fields in different districts of the investigated provinces.The average population densities of CCN in collected samples are completely different.The CCN occurred quiet common in winter wheat field of Yucheng County,Shangqu District of Henan Province,with high population density and causing serious damage to wheat growth.The occurrence of CCN was common in spring wheat field of Qinghai Province,however with low population densities.Except in Qinghai Province,the cultivation of winter wheat in other investigated provinces rotated with maize during one year season and the soil property is sandy clay in most areas.This popular cultivation system can cause rapid accumulation of cysts in soil and result in the damage to wheat increasing steadly through years.The integrated control of CCN on wheat was studied under field conditions.Seven treatments were designed,including the seed-coating chemical No.1 and No.2,BT biocontrol agent with concentrations of 1/30,1/45 and 1/60,and avermectin granular(GR)with dosage of 30 kg/hm2 and 60 kg/hm2,respectively.The result showed that the population densities of CCN were all inhibited after treatment with the seed-coating chemicals No.l and No.2,BT biocontrol agent with concentration of 1/30,as well as the avermectin GR with dosage of 60 kg/hm2,respectively.The treatment of avermectin GR with dosage of 30 kg/hm2 had effects not only on high inhibition to CCN population density but also on promotion of wheat yield.Therefore,the dosage of 30 kg/hm2 of avermectin GR is suggested to be applied in wheat-regreening period,which might decrease the yield loss caused by CCN to some extent.