Effects Of Intercropping Green Manure In Apple Orchards On Occurrence Dynamics And Time Niche Of Pests And Natural Enemies

The perennial single fruit tree cultivation mode not only cause some problems like soil fertility decline,soil acidification,organic deficiency,etc.but also aggravate the occurrence of diseases and insect pests.The continuous increase of fruit tree planting area in Xinjiang raised the importance of these problems.For this reason,production costs have been increased.The compound cultivation mode of growing grass in orchards can solve the problems well such as the decline of soil fertility and the occurrence of a large number of diseases and insect pests in the orchard.It also significantly improves the fruit quality and reduce the production cost.My thesis has the following objectives: the occurrence dynamics and damage law of pests in intercropping green manure orchard in southern Xinjiang;the effects of intercropping green manure on pest natural enemies;and the population richness and niche of pests and natural enemies in intercropping green manure orchard were analyzed.The relationship between pests and natural enemies,which provided a theoretical basis for the ecological regulation of orchard pests,was clarified.1.The species of pests and natural enemies in orchards were investigated by systematic investigation.The results showed that there were 32 species(including mites)of pests in the orchard,belonging to 9 orders and 20 families,including Cydia pomonella,Lithocolletis ringoniella,Euzophera pyriella,Aphis citricola,Crapholitha molesta,etc.There are 17 species of natural enemies,belonging to 9 orders and 12 families,and the common species are Chrysoperla sinica,Chrysopa phyllochroma,Coccinella undecimpunctata,Hippodamia,etc.Intercropping alfalfa in orchards increased the population of natural enemies by 15%compared to annual green manure crops intercropped with alfalfa,and 55% compared to in clear orchards.2.The results on the time niche of pests and natural enemies in intercropping green manure apple orchard showed that among intercropping alfalfa,annual green manure crop and clear ploughing apple orchard,the species richness of Aphis citricola was the highest,which were 0.5298,0.5546 and 0.5728,respectively,followed by Lithocolletis ringoniella;The highest temporal niche breadth was Lithocolletis ringoniella which was 0.823,0.814 and 0.754 respectively,followed by Chrysopa sinensis;The highest niche overlapwas Aphis citricola,which was 0.882,0.812 and 0.684,the second was Coccinellidae,0.642,0.543 and0.435.After planting alfalfa and annual forage in the orchard,it has a greater impact on the population dynamics and number of pests and natural enemies in the orchard.Compared with the clear cultivation,the abundance and niche breadth of alfalfa and annual forage orchards have increased,and natural enemies The niche overlap index of pests has increased.3.The occurrence dynamics of adults of Cydia pomonella,Crapholitha molesta and Euzophera pyriella were monitored by pheromone technique.in three different apple orchards,the occurrence of Cydia pomonella Euzophera pyriella had 4 peaks in a year,and Crapholitha molesta had 5 peaks in a year.The annual trapping amount of Cydia pomonella was clear tillage area > intercropping alfalfa area >intercropping annual grass area,Euzophera pyriella was clear tillage area > intercropping annual grass area > intercropping alfalfa area,and Crapholitha molesta was intercropping annual grass area >intercropping alfalfa area > clear tillage area.4.The results of systematic investigation on Aphis citricola and its natural enemies showed that the occurrence number of Aphis citricola in clear orchard was much higher than that in apple orchard where intercropping green manure crops were intercropped.The peak number of 866 branches per 30 cm in mid-July was 1.15 times more than that of intercropping annual green manure area and 1.45 times more than that of intercropping alfalfa.The number of natural enemies in clear orchard was lower than that in intercropping green manure orchard.During the peak period,the occurrence amount of lacewings in alfalfa orchard was 1.1 times as much as that in intercropping annual forage orchard and 1.4 times that in clear ploughing orchard.The occurrence of Lygus pratensis was 1.2 times more than that of intercropping annual forage and 1.5 times more than that of clear ploughing orchard,and the occurrence of aphid flies was 1.1times more than that of intercropping annual forage orchard and 1.3 times that of clear ploughing orchard.5.three orchard apple orchards in southern Xinjiang were selected,and the use of pheromone traps and field survey methods was conducted to study the occurrence rules of Lithocolletis ringoniella and the degree of harm caused by different ground management models.Prevention measures were also put forward.The research shows that five generations of Lithocolletis ringoniella occurred in southern Xinjiangin one year.The most frequent period was August,and the average trapping amount reached 1384 heads /board / week in the peak period.The degree of harm in different ground management modes was clear-cultivated orchards orchard > Intercropping 1-year pasture orchard > Intercropping alfalfa orchard.The damage degree and occurrence amount are different in different planting modes.The leaf damage rate,insect index,and trapping amount are all clear-cultivated orchards> Intercropping 1-year pasture orchards> Intercropping alfalfa orchards.Intercropping of alfalfa and annual forages in orchards will reduce the occurrence of Lithocolletis ringoniella.