Investgation To Occurrence Dynamics Of 4 Main Species Pest Of Jujube Orchards In Alaer City And The Influence Of Jujube Black Rot On Quality Of Jujube Fruits

Object: The purpose of this study is a)to clarify the occurrence dynamics of 4 main pests of jujube orchards in Alaer city;b)to find out the early infection period of jujube black spot disease,which is the primary disease;c)to clarify the impact of the black spot disease on the quality of jujube fruits.Based on these study,a theoretical basis to control main diseases and pests of jujube orchards and scientific evaluation of the influence of black spot disease on jujube industry in Alaer city will be provided.Methods: The damage degree and growth and decline regularity of jujube black spot disease,jujube fruit shrink disease,Dasineura datifolia.larva and jujube spiders in different irrigation patterns,fruit setting of branches and pruning patterns were investigated by using field-time and fixed-point survey method.To understand the relevance between orchard conditions and disease occurrence,the effect of different jujube varieties,different ages and different planting density on jujube black spot disease was surveyed.The period of early infection was researched by detecting the amount of fungi with the specific primers of A.alternata.Moreover,the impact of black spot on the quantity and quantify of jujube were investigated by comparing the appearance,internal quality,and Alternaria toxin species.Result:1.Jujube black spot disease emerged from the end of August in the field,then outbreak in large scale in late September and become more severe with the fruit ripening,and there are still lots of disease before harvest.Jujube fruit disease started in early July in the field,the incidence showed a trend of decline after rising first.Subsequently,the incidence reached peak in early August.Finally,it remained stable as as fruit ripening at the end of september.Dasineura datifolia.larva had three high-incidence throughout a year.They were jujube early germination periods with leaf expansion(early May),branching development periods with leaf growing(early June)and full-bloom stage(the end of June),respectively.The first generation of larvae had the largest population and caused most serious injury.The occurrence rate of jujube spiders had two peak stages in the year,which began with leaves damaged in late July,followed with explosion widely in late July,reached peak as the rise of temperature in early August.2.Jujube black spot disease,jujube fruit shrink disease and jujube spiders in furrow irrigation orchard were serious.However,Dasineura datifolia.larva caused severe destroy in drip irrigation orchard.By contrast,jujube black spot disease,jujube fruit shrink disease and jujube spiders were serious in old bone jujube orchard,but Dasineura datifolia.larva was critical in the new branching jujube orchard.We compared excessive pruning jujube orchards with normal pruning jujube orchards,four diseases and insect pests of the former were moreserious than latter.The black spot disease in jujube cv.Juizao orchard was significantly higher than jujube cv.Huizao orchard.The black spot disease was mild in three years jujube orchard,with the age of jujube increasing,incidence increased in 6 to 12 years jujube orchard.The black spot disease was mild in planting density of 1 m×3 m,and the incidence was not significantly different from three other planting density.3.In the jujube flower and different parts of fruit,A.alternata were isolated.And the RT-PCR results showed that it was the highest in pulp,followed by in peel,it was the lowest flower.The amount of fungi was 20.12?g/100 mg in the bottom flesh of the trunk,was11.48?g/100 mg in the bottom peel,was 9.34?g/100 mg in the carpopodium flesh,was3.84?g/100 mg in the carpopodium peel,was 2.11?g/100 mg in the flower.4.The fresh fruit weight of cv.Juizao infected with black spot reduced and fresh fruit weight of cv.Huizao increased comparing with healthy fruit.But,both fruit shape index of two jujube species increased,while hardness and water content decreased.After infected with black spot,peel brightness,color saturation,vitamin C significantly reduced,the color became scarlet.Soluble protein,free amino acids,soluble sugars,reducing sugar content increased,the titratable acid content decreased and even lower(but in the severe jujube fruit is low).Three toxins,namely TeA,AME and AOH were all detected in jujube cv.Juizao and cv.Huizao,respectively.The average content of TeA is 1.17-217.42(mg/kg),AME is0.68-3.81(mg/kg),AOH is 0.04-2.24(mg/kg),ALT was not detected.