Evaluation On Harm And Loss Of Cereal Cyst Nematode (H.avenae) In Taian Shandong Province And Preliminary Study On Its Control Measures

Cereal cyst nematode has been widely spreaded in China’s wheat-growing regions andposes a great threat to wheat production. This article investigated the occurrence, distributioncharacteristic, damage and loss of CCN in wheat cultivation sites of Tai’an and surroundingareas in detail, conducted a preliminary study on its control measures combining withscreening of resistant varieties and chemical control means. The main contents and resultswere as follows:1、 In June2011before wheat harvested, we investigated the occurrence of CCN in wheatcultivation sites of Tai’an and surrounding areas by sampling. we collected96effectivesamples,82survey sites were detected with CCN cysts, detection rate was68.75%, thehighest of identification amount was87cysts per200ml. In addition, CCN distributednon-homogeneous and places which were near water, roads or low-lying land were greaterserious than the other places in Hutun, Manzhuang Taian and Yangzhuang Laiwu.Furthermore, CCN was spreaded from the places with CCN cysts to the center places of aland.2、 In the Hutun town which had better water and fertilizer conditions, the grain yield perspike increased with the increase in the cyst number per spike when the cyst number per spikewas lower than3.75, the highest grain yield per spike was1.91g. The grain yield per spikedecreased with the increase in the cyst number per spike when the cyst number per spike wasmore than3.75, and the change was not obvious when the cyst number per spike was morethan6.00. In the Manzhuang town which had worse water and fertilizer conditions, the grainyield per spike decreased with the increase in the cyst number per spike when the cyst numberper spike was more than2.40, and the highest loss rate25.00%. In the Yangzhuang town, thecyst number per spike was lower than2, and there is no obvious relationship between the twonumbers. The results of yield loss test showed that the wheat yield per unit area decreasedwith the increase in CCN infect dose, and the susceptible variety were more obvious thanresistant variety. The main reason is to reduce the effective panicles of wheat, there was nosignificant effect on grain number and thousand-grain weight.3、 CCN was only one generation from wheat planting to harvest in the three experimental plots, and there was no infection phenomenon before winter. CCN larvaes were found in earlyFebruary, and began to increase, the number of nematodes reached a peak in mid-April, thenstarted to decrease. Light brown cysts were found in the soil in mid-May. CCN infectiondynamics is basically the same in the three experimental plots.4、 The results of resistance identification by inoculation showed that there were five highsusceptible varieties, five moderately susceptible varieties, five medium resistance varietiesand no high resistance variety to Heterodera avenae among fifteen tested wheat varieties. Theresults of resistance identification in field showed that there were only two resistance varietiesto Heterodera avenae among the same fifteen tested wheat varieties. There were nine highresistance varieties to Heterodera avenae among sixteen tested wheat varieties from ChengduInstitute of Biology, Chinese Academy of Sciences. In the roots of resistance variety, theenzyme activity of SOD, POD and PAL appeared a higher level of increase in3to9days afterinoculation.5、The result indicated that the toxicity sequence of six nematicides to CCN J2was ranked asfollows: emamectin benzoate> abamectin> ethoprophos> aldicarb> fosthiazate>carbosulfan. The susceptibilities had some difference among different regions. The study alsofound that Some organic solvents had obvious inhibition effects to Heterodera avenae. Thesesolvents if can increased the control efficiency of nematicidal agents, would be very useful foroptimizing nematicide formulations.6、 For the control of CCN in field, the control efficiency of seed coated with a pesticide wasbetter than granular formulation, especially the aqueous capsule suspension, could extend theduration of the efficacy. There was a better control efficiency using emulsifiable concentrateformulations in wheat turning green period than using seed coated with a pesticide in wheatsowing stage, because this time was the fastigium of CCN hatching and infecting.