Document Type : Original Article
Author
Biological Control Research Dept., Plant Protection Research Institute, A.R.C., Dokki, Giza, Egypt.
Abstract
In Egypt, the red cabbage Brassica oleracea var. capitata L. (Cruciferae) is considered as one of the most important vegetable crops. It is liable to attack by many major piercing-sucking insectś pests; such as the whitefly, Bemisia tabaci (Genn.) and the cabbage aphid, Brevicoryne brassicae (L.). However, the present study was conducted to evaluate the effect of utilizing the natural compound Spinosad (Tracer 24%) against the population densities of these two common pests and also on the formation of the mummies of the parasitoid Diaeretiella rapae (McIntosh) parasitizing the cabbage aphid. The occurrence periods of thewhitefly, B. tabaci were extended from November, 2017 to April, 2018. The percentage of reduction in the population density of thewhitefly, B. tabaci per season was 62.53%, in comparing the untreated control with that treated by the natural insecticide Spinosad. As for the cabbage aphid, B. brassicae, the occurrence period was extended during the whole season expect the last week of November, 2017. The percentage of reduction in the population density of the cabbage aphid, B. brassicae per season was 70.14%. The aphid parasitoid D. rapae was the only common recorded parasitoid́ species parasitizing the cabbage aphid, B. brassicae attacking the red cabbage plants. The highest total numbers of the mummies of the parasitoid D. rapae (164 & 56 individuals) were recorded during the first week of March, 2018 and the third week of February, 2018, in case of the untreated control and the treatment, respectively. The mean total numbers of the mummies of the parasitoid D. rapae per season were; 54.00±13.01 and 12.07±4.01 mummies, in case of the untreated control and the treatment, respectively. The highest population densities of the mummies of the parasitoid D. rapae (450 & 177 aphid mummies) were recorded during the months of March and February, in both of the untreated control and the treatment, respectively. The percentage of reduction in the total numbers of the formed mummies of the aphid parasitoid D. rapae parasitizing the cabbage aphid, B. brassicae was 21.24%.The natural compound Spinosad can be used against the whitely, B. tabaci and the cabbage aphid, B. brassicae on the red cabbage plants or other plants that are subjected to these pests attack. Besides, the occurrence of less harmful effect on the formation of the parasitoid D. rapae mummies, in the frame of Integrated Pest Management (I.P.M.), side by side with other safe control methods, for giving less pollution to the surrounding environment.
Keywords
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