Role of faba bean planted around and within sugar beet fields on insect infestations \

الملخص EN

Faba bean is a good source of pollen and nectar for attracting natural enemies of insects, also it is a major source of protein for human and animals feeding in Egypt.

Therefore, the present study was conducted at Tayfa village, Kafr El-Sheikh Governorate during 2017/2018 and 2018/2019 for investigating the role of faba bean planted around and within sugar beet fields (not intercropping) on insect infestations, natural enemies and farmer income.

Obtained results demonstrated that mean numbers of infested plants (10 plants each replicate) with beet fly Pegomyia mixta Vill.

(Deptera: Anthomyiidae), beet moth Scrobipalpa ocellatella (Boyd.) (Lepidoptera: Gelechiidae), tortoise beetle Cassida vittata Vill.

(Coleoptera: Chrysomelidae) and aphid ( Aphis spp.) in a sugar beet + faba bean field were recorded 3.00, 2.67, 2.33 and 4.50 in the first season, while, in the second season it recorded 3.67, 2.00, 4.00 and 5.00, respectively, while, in a sole sugar beet field the mean numbers of infested plants were 5.44, 6.56, 6.11 and 6.56 in the first season and 6.33, 6.16, 8.06 and 7.94 in the second season, respectively.

Data also cleared that field mixed beet and faba infestation by beet fly, beet moth and tortoise beetle were beginning about 2 months (on February 25) later than sole beet, while, aphis infestation was beginning in the same time in both treatments.

Statistical analysis proved significant differences between both fields during the both seasons have been detected.

Further, total population of natural enemies, Chrysoperla carnea Steph.

(Neuroptera: Chrysopidae), Syrphus corollae Fabricius (Diptera: Syrphidae), Coccinella undecimpunctata L.

(Coleoptera: Coccinellidae), Scymnus sp.

(Coccinellidae: Coleoptera) as predators and Opius nitidulator Nees (Hymenoptera : Braconidae) , Monorthochaeta nigra Blood (Hymenoptera : Trichogrammatidae) , Agathis sp.

(Hymenoptera:Braconidae) and Diadegma oranginator Aubert (Hymenoptera:Ichneumonidae) as parasitoids in a sugar beet + faba bean plant were recorded 30.22 and 42.33 during 2017/2018 and 2018/2019, respectively.

Whereas, in a sole sugar beet plant were recorded 7.06 and 7.39 in both seasons, respectively.

Meantime, the additional return beside price the main crop was 1690 and 1470 L.E (Egyptian pound) to a sugar beet + faba bean in comparison with a sole sugar beet field.