Seasonal abundance of the prevalent arthropods inhabiting cowpea plantations with reference to the relative susceptibility of certain cowpea cultivars to the main sap sucking pests

Abstract

Species composition, dominance, and seasonal abundance of the prevalent arthropod pests and associated natural enemies inhabiting cowpea plantations during the 2020 and 2021 cowpea growing seasons were evaluated in Assiut Upper Egypt. Except for the two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae), the obtained results revealed the presence of 23 arthropod species belonging to 14 families and 7 insect orders in association with cowpea plantations. The collected species were divided into 5 groups. Group1 contained 12 phytophagous species, group 2 contained 3 predominantly phytophagous (predacious in part) species, group 3 contained 6 predatory species, group 4 contained 1 predominantly predacious (Phytophagous in part) species and group 5 contained 1 parasitoid species. Concerning the dominance percentages of the phytophagous group, Empoasca spp. ( Hemiptera: Cicadellidae) ranked the first in both seasons with an average of 84.63 and 89.84 %, respectively. In the predatory group, the ladybird beetle Coccinella undecimpunctata (L.) (Coleoptera: Coccinellidae) ranked first in the first season with an average of 41.10 %. However, Orius spp.(Hemiptera: Anthocoridae) ranked first in the second season with an average of 44.84 %. It is important to note that the predatory group constituted 5.12 and 9.03 percent of the phytophagous group during both seasons of study, respectively. The examination of cowpea leaves revealed the presence of three sap sucking species viz. Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), Thrips tabaci Linderman (Thysanoptera: Thripidae) and T. urticae. The tested cowpea cultivars showed diverse susceptibility degrees against the leaves sap sucking arthropod pests. In general (Kafr-Elsheikh1 and Kaha1) appeared as low resistant (LR) cultivars against the whitefly B. tabaci, the leafhopper T. tabaci and T. urticae. Resistant cowpea cultivars were hoped for but not found. Therefore, cowpea cultivars that showed some sort of resistance can be included among advanced breeding programs to select new varieties resistant to sap sucking pests infesting cowpea plantations.