Investigation Of The Insect Pest Species And The Technology For Controlling Of The Main Pests In Zhaoxian County Pear Orchards

Zhaoxian County is an advantageous pear producing area in Hebei Province.In recent years,the occurrence of pests and diseases has seriously affected the safe production of fruit and the development of the pear industry.To clarify the pest species and their hazards in the pear orchards in Zhaoxian County and draft a comprehensive control technology program,we conducted investigations and studies on the main pest species and their occurrence patterns,and clarified that Grapholitha molesta,Psylla chinensis and Aphanoaigma jakuauiense are the main pests in pear orchards in Zhaoxian County.The dynamics and control techniques of the major pests Oriental Fruit Moth were studied,and a comprehensive control technology program was proposed.The results are as follows:1.Investigated the main pest species in pear orchards of Zhaoxian CountyThe main pest species in Zhaoxian pear orchards were investigated in 2016-2017.26pest species were found,which belonging to 4 orders and 20 families;and also 7 natural enemies were found,belonging to 6 orders and 6 families.Among them,the Grapholitha molesta,Psylla chinensis and Aphanoaigma jakuauiense caused serious damage,so they were the main pests.The survey found that the interplanting grass pear orchards had 9 pest species and 4 natural enemy species more than the no grass orchard.2.The population dynamics of major pests in pear orchards in Zhaoxian County have been clarified(1)The population dynamics of Grapholitha molesta in pear orchards was observed for two years in 2016-2017.Four generations occurred in per year,The peak period of the four generations occurred on May 27-29,July 4-6,August 5-8,and September 4-7respectively.As the temperature rises,the emergence time of overwintering adults has an early-stage trend.The population dynamics of Grapholitha molesta were investigated in six different pear varieties orchards which are Xueli,Yali,Xueqing,Huangguan,Qiuyue and Zaosuhong.It was found that the growth curves of the Grapholitha molesta adults were basically similar,and that the peak period of each generation of the adults were basically the same,but the occurred amount was very different between varieties.The Xuehua occurred the most,then come with the Yali,and the Zaosuhong occurred the least.(2)The population dynamics of Psylla chinensis in pear orchards was observed.The Psylla chinensis occurred four generations in Zhaoxian County.The peak period of the overwintering generation was Mar 15,and the peak period of 1-4 generations were May 15,June 8,July 8 and August 15 in 2017,respectively.As the temperature drops,the adults look for places to overwinter.(3)The population dynamics of Aphanoaigma jakuauiense in pear orchard was observed in 2017.Aphanoaigma jakuauiense occurred many generations and it occurr much more amount,the generations overlapped seriously.When the pear sprouted,the adults emerged and damaged the young shoots.When the little fruits expended(the end of May and the beginning of June),the eggs reached to the peak.When the fruits close to maturity(the end of July and the beginning of August),the amount of adults reached to the peak.3.The control efficiency of different measures for contolling Grapholitha molesta(1)Sex pheromone lures trapping to control Grapholitha molesta:Five traps were hung in per 667 m~2 in 2016-2017.8189 males and 13,044 males were trapped each year.The average annual trapping amount was 1637 and 2608 respectively.So the sex pheromone lures trapping could reduce the population density of Grapholitha molesta.(2)The sweet and sour liquid trapping Grapholitha molesta:In 2017,the mating disruption orchard,the total amount of moth trapped by sweet and sour liquid was 320,while the total amount of moth trapped by sweet and sour liquid was 929 in the control area.Of which,589 were female moths,accounting for 63.40%of the total moths investigated.In mating disruption area,the sweet and sour liquid trapped much lower than that in the control area,which indicated that the combination of sweet and sour liquid and the mating disruption could significantly reduce the occurrence numbers of Grapholitha molesta.(3)Mating disruption technology:Before the adults moths of overwintering generation emerged,mating disruption filaments were hung on pear trees.Each tree hung 1filament.In 2016,the average mating disruption rate was 95.71%.In 2017,the average mating disruption rate was 97.84%.In mating disruption area,the occurrence amount was much lower than that in control area,which showed that the sex pheromone mating disruption significantly reduced the population of Grapholitha molesta,and it could control the Grapholitha molesta effect.4.The effects of Interplanting grass on population of Psylla chinensis and Aphanoaigma jakuauiense in pear orchardsThe amount of Psylla chinensis were investigated in no grass pear orchard,man planting grass and wildly growing grass pear orchards in 2017.The results showed that there were no significant differences in generations occurred,but the adults amount in hundred leaves in different orchards were 3393.34,2898.67,and 2740.67 respectively in no grass pear orchard,man planting grass,and wildly growing grass pear orchard.The population of Psylla chinensis in no grass pear orchard was significantly greater than that of the other two grass planting orchards.The amount of Aphanoaigma jakuauiense adults in hundred fruits were 6017 in no grass pear orchard,4771 in man planting grass pear orchard,and 5547 in the wildly growing grass pear orchard.There were 5,563 nymphs in hundred fruits in no grass pear orchard,4869 nymphs in the man planting grass pear orchard,and 5,919 nymphs in the wildly growing grass pear orchard.The number of nymphs and adults in man planting grass pear orchard has significantly decreased.