Effect of intercropping systems of sugar beet and red clover on biological control of Aphis fabae (Hem.: Aphididae), natural enemies, and agronomic traits of sugar beet

Cultivation of diverse crops is a strategy key in sustainable agriculture. Increasing plant diversity in intercropping systems can be suitable for biological control of pests. In order to investigate the effect of mixed cultivation of sugar beet and red clover on the population of Aphis fabae Scopoli, natural enemies including Coccinella septempunctata Linnaeus, Hippodamia variegata Goeze, Orius niger Wolf, O. minutus Linnaeus, and Chrysoperla carnea Stephens, and some agricultural traits of sugar beet, an experiment was conducted in the form of completely randomized block design in four replications. Experimental treatments included monoculture of sugar beet (control) and seven types of strip cultivation systems including: 1) two rows of sugar beet  and four rows of red clover, 2) two rows of sugar beet and three rows of red clover, 3) one row of sugar beet and two rows of red clover, 4) two rows of sugar beet and two rows of red clover 5) three rows of sugar beet and two rows of red clover, 6) two rows of sugar beet and one row of red clover, 7) four rows of sugar beet and two rows of red clover. The results of this research showed that the different treatments of sugar beet and red clover intercropping on the aphid population, natural enemies, and agricultural traits including root yield, leaf yield, and shoot yield are significant at 1% probability level. The results of this research showed that the treatment of two rows of sugar beet and four rows of red clover can be useful in integrated pest management and biological control of A. fabae in sugar beet fields and improve agricultural traits.