Study On The Diversity Of Arthropod Community In The Apricot Orchards Intercropping With Wheat Or Cotton

Apricot is one of the main fruit trees in Xinjiang, and cultivated as an important composition of the horticulture development project in Tarim Basin. However, pest control poses a serious challenge for the apricot culture which is under serious threat from insect pest outbreaks. For this reason, This thesis study was designed to evaluate the apricot-crop intercropping system with a focus on characteristics of the arthropod community in the system. The arthropods were surveyed and analysed in species diversity, structure, and their seasonal dynamic in four apricot orchards. The population fluctuation of the aphid Hyalopterus amygdali and its natural enemies were also investigated.The survey uncovered 280 species,73 families and 14 orders, in which 189 species in 61 families from 13 orders were obtained from young apricot orchards intercropped with wheat, and 175 species in 62 families from 14 orders from young apricot orchards intercropped with cotton,57 and 192 species in families from 13 orders from the old apricot orchards intercropped with wheat, and 120 species in 46 families from12 orders from the old apricot orchards without intercropping. Homoptera insects were the dominant herbivorous groups, in which Hyalopterus amygdali Blan is the dominant species in apricot orchards, Macrosiphum avenae F in the wheat filed, Aphis gossypii Glover in the cotton field. Hymenoptera insects and Araneida spiders were main natural enemies. The species diversity varied with the growth and development of the apricot, environment factors, climate, and intercropped plants. In 2009 the diversity index of the community was greater than that in 2010 due to the climate stability. H. amygdali played a major role in the community stability in apricot sub-systems, where its occurrence was associated with low diversity and evenness indices. The diversity and evenness were greater at the stage of leaf expansion, fruit setting, and harvest time. In the old apricot orchards intercropped with wheat and without intercropping the number of species increased. The aphid H. amygdali population was greater in apricot orchards without intercropping than with. The analysis using Jaccard similarity index and clustering showed that different sub-communities of arthropods were similar inλ(= 0.4858), and arthropod communities in apricot orchards with intercropping were clustered into one group while that in apricot orchards without intercropping another different group. Through investigation and study of the community succession of natural enemies in apricot-crop intercropped system, in the apricot sub-systems and crops sub-systems have same natural enemies, Ladybugs, lacewings and spiders were distributed on the tree and under the tree. Apricot and crops can be used as refuge places for the insect natural enemies to migrate between. But the spiders were influenced by the crops. The study of niche of major natural enemies of H. amygdali showed that Ephedrus sp is the main parasitoid that should be protected.