Ecological Studies on the Biological Integration Occurred by the Two Predators; Coccinella undecimpunctata L. and Hippodamia convergens Guer. (Coleoptera: Coccinellidae), Following the Primary Parasitism Process of the Aphids on the Wheat Plants in Qalubia Governorate. | ||
| Egyptian Academic Journal of Biological Sciences. A, Entomology | ||
| Article 18, Volume 13, Issue 2, June 2020, Pages 229-255 PDF (439.16 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/eajbsa.2020.91645 | ||
| Authors | ||
| Bahy El-Din, I. A.; El-Khawas, M. A. M. | ||
| Biological Control Research Dept., Plant Protection Research Institute, A.R.C., Dokki, Giza, Egypt | ||
| Abstract | ||
| Many aphidsˈ species are considered as the most serious insectsˈ pests that attack the wheat plants in Egypt, from planting date up to the harvesting time of the crop. Therefore, the present field study was carried out to estimate the population density of the wheat aphidsˈ species, the related parasitoids (either the primary or the secondary ones) and also the common predators of familyCoccinellidae, which occurred on the wheat plants, during the two successive seasons 2017/2018 and 2018/2019, in Qalubia Governorate. The natural positive and negative relationships that were existed between the wheat aphidsˈ species and these common natural enemies were also studied. However, it is necessary for effective successful biological control programs to study the natural enemies’ activity, to evaluate the impact degree on the pests’ populations, and also to detect the need for any additional control measures to be applied. So, the obtained results revealed that the occurrence periods of the aphids’ species on the wheat plants were extended during the whole period of the wheat plantation (i.e., from the period extended from December to April), of the two studied seasons, 2017/2018 and 2018/2019. The total numbers of the wingless individuals were higher than those of the winged adults on the wheat plants. In addition, the total number of the aphids’ population in the second season (2018/2019) was higher as compared with that recorded in the first one (2017/2018) of the study. Theaphidsˈ parasitoids immediately appeared in the wheat fields after the beginning of the aphidsˈ infestation, where the percentages of the aphidsˈ species parasitism were relatively lower in the two growing studied seasons. The primary parasitoid Aphidius colemani Viereck was the predominant parasitoid species recorded attacking the aphidsˈ species in the wheat fields, in comparison with the other recorded primary parasitoids. Where, the recorded primary parasitoids (Hymenoptera: Aphidiidae) were arranged according to the mean percentages of their occurrence to each others for the two seasons of the study as follows: A. colemani (52.03% (0.00-56.66%)) > Ephedrus sp. (mostly E. persicae Froggatt) (33.94% (0.00-54.55%)) > Lysiphlebus sp. (10.41% (0.00-18.18%)) >Diaeretiella rapae Mclntosh (3.62% (0.00-14.28%)). As for the secondary parasitoidsˈ species, their total numbers were higher in the first season (2017/2018) in comparing with the second one (2018/2019) and they were also higher in their total numbers than those of the primary one, in the two investigated seasons. The mean percentages of the occurrence of the secondary parasitoids (the hyperparasitoids) species to each other for the two seasons of the study were; Dendrocerus spp. (Megaspilidae) (65.60%) > pteromalids spp. (Pteromalidae) (34.40%) and the period of their occurrence extended from January to April, in 2017/2018 and 2018/2019 seasons. Moreover, the obtained results revealed that the mean total numbers of adults of the two common recorded predatoryˈ species of family Coccinellidae, of the two seasons, were; Coccinella undecimpunctata L. (162.50(0-103 adults)) > Hippoddamia convergens Geur. (98.00 (0-87 adults)). The period of predatoryˈ species occurrence extended from January to April, in the two seasons (i.e., the period of the occurrence the covered the four months of the wheat plantation). As a result, the natural sequence role of the two biocontrol agents; the primary parasitoidsˈ species and the two major ladybirds’ predators (C. undecimpunctata and H. convergens), must be continuously encouraged and developed) in the wheat fields by maintaining the suitable safe conditions to do such important natural role. Also, in the view of the natural occurrence of the previous biocontrol agents, they can be massed reared in the laboratory and released for controlling the aphidsˈ species on the wheat plants or the other related plants that are subjected to the aphidsˈ attack. They can be applied side by side with the other available safe control methods, in the frame of Integrated Pest Management (I.P.M.) programs, for protecting man heath and the surrounding environment from pollution. | ||
| Keywords | ||
| Wheat; Aphids; Population density; Integration effect; Natural enemies; Parasitism; Primary parasitism; Hyperparasitism; Coccinellidae; Ladybird predators; Coccinella undecimpunctata; Hippodamia convergens | ||
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