[Relationships between Aphis gossypii and its natural enemies in megranate field]

In this paper, the relevancy of Aphis gossypii with its natural enemies was studied by using grey systematic analysis. The results showed that the major natural enemies of Aphis gossypii were Tetragnathidae (0.8607), Therdion octomaculatum (0.8058), Therdion octomaculatum (0.7989), Haramonia aiyridis (0.7881) and Chrysopa sepetempunctata (0.7758). As for the daily total predation, the natural enemies which highly associated with the ideal dominant natural enemies were Erigonidium graminicola (0.8975), Tromobidiidae (0.8132), Propylacea japonica (0.7806) and Chrysopa sepetempunctata (0.7669); while for the quantity, Erigonidium graminicola (0.8482), Chrysopa sinica (0.7533), Tetragnathidae (0.7532), Therdion octomaculatum (0.7411) and Chrysopa sepetempunctata (0.7716) were the major natural enemies. According to the relational grade of the individuals between various natural enemies and ideal dominant natural enemies, the major natural enemies were Erigonidium graminicola (0.8461), Tromobidiidae (0.7325), Propylacea japonica (0.6983), Chrysopa sepetempunctata (0.6815) and Chrysopa sinica (0.6757). The species having >0.9567 horizontal and vertical niche overlaps with Aphis gossyppii were Erigonidium graminicola, Chrysopa sepetempunctata and Tetragnathidae, while the temporal niche overlaps between Erigonidium graminicola, Chrysopa sepetempunctata, tetragnathidae and Aphis gossyppii were >0.4020. It could be concluded that the main natural enemies of Aphis gossyppii were Erigonidium graminicola, Chrysopa sepetempunctata and Tetragnathidae.