Role of Parasitoids, Conventional Insecticides and Ecdysone Agonists in Regulating Population of Cassida vittata Vill in Egyptian Sugar Beet Fields

Abstract

This study was carried out at the experimental farm of Sakha Agricultural Station, Kafr El-Sheikh Governorate for three successive seasons (2017/2018, 2018/2019 and 2019/2020). The study aimed to monitor seasonal abundance of Cassida vittata Vill. (Coleoptera: Chrysomelidae) and its hymenopterous parasitoids, Monorthochaeetaa nigra Blood (Trichogrammatidae) and Dinarmus laticeps (Pteromalidae). Further, role of ecdysone agonists compounds in reducing C. vittata numbers and their adverse effect on these parasitoids in comparison with the conventional insecticides. Results proved that population density of C. vittata and its parasitoids gradually increased towards the end of the season resulting in highly positive significant correlations between this insect and its parasitoids. General egg-parasitoid of M. nigra to host ratio was 1:1.88 and 1:1.96, while it was 1:1.61 and 1:1.44 for larval-pupal parasitoid D. laticeps during 2018/2019 and 2017/2018 seasons, respectively. Lastly, ecdysone agonists were efficient against C. vittata, whereas it were almost safer to parasitoids than conventional insecticides. Thus, C. vittata parasitoids and ecdysone agonists may be used for integrated pest management programs for this serious insect.

Survey, Population Density and Food Preference of Predatory Formicid Species on Scrobipalpa ocellatella Boyd. Life Cycle Stages under Egyptian Sugar Beet Fields

“…In Egypt, the status of insect predators and parasitoids in sugar beet fields was investigated by several authors (Abo-Saied Ahmed, 1987;Youssef, 1994;El-Agamy, et. al., 1996;Awadalla, 1997;Abou-Attia, 1999;Bazazo, 2005 andFatma H. Hegazy andEl-Sheikh, 2021) Formicid species are very effective biocontrol agents for several reasons; colonies contain large numbers of individuals that consume large populations of prey and their predation is not limited to a particular prey species or stage (Paulson and Burts, 1993). As well, in many countries, several studies have demonstrated that ants can be key generalist predators of crop pests (El-Keroumi et al, 2010;Fernandes et al, 2010 andSanders &Van Veem, 2011).…”