APHIDOPHAGOUS SYRPHID PREDATORS AND THEIR PARASITOIDS ON MAIZE PLANTS | ||||
| Zagazig Journal of Agricultural Research | ||||
| Volume 51, Issue 5, September and October 2024, Page 971-989 PDF (599.74 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/zjar.2024.391947 | ||||
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| Authors | ||||
Walaa M. M. Helaly; Sherin M.M.Y. Helaly; M.A.I. Youssif 
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| Plant Prot. Dept., Fac. of Agric., Zagazig Univ., Zagazig, Egypt | ||||
| Abstract | ||||
| Survey and population densities of aphidophagous syrphid predators and their insect hyperparasitoids on maize plants infesting with aphids namely, Rhopalosiphum maidis (Fitch) and Rhopalosiphum padi (Linnaeus) at El-Deeb village, Abou-Kbeer district, Sharkia Governorate, Egypt were studied during 2022 and 2023 seasons. The obtained results were summarized as follow: six species of aphidophagous syrphid belonging to family Syrphidae namely, Xanthogramma aegyptium Wied., Sphaerophoria flavicauda Zett., Paragus aegyptius Macq., Paragus spp., Metasyrphus (=Syrphus) corollae (Fabr.) and Scaeva albomaculata Macq were surveyed on maize plants infesting with aphids. The total relative densities of the syrphid species were 34.17, 23.92, 18.54, 10.36, 7.22 and 5.79 % of the total number of hoverfly, successively. The total numbers of aphidophagous syrphid predators were fluctuated, showing a distinct peaks of 343 and 371 predators/sample in the 2nd and 3rd weeks of August during the first and second seasons, consecutively. The highest total monthly counts of 1016 and 1299 predators recorded in August during two successive seasons 2022 and 2023, consecutively. The means of syrphids : prey ratio were 1 : 28.76 and 1 : 22.59 during two successive seasons. Five species of hyperparasitoids belong to four families were recorded parasitized on syrphid species namely, Telenomus acrobats Giard, Telenomus sp. (Scelionidae), Diplazon laetatorius (Fabricius) (Ichneumonidae), Syrphophagus aphidivorus (Mayr) (Encyrtidae) and Tetrastichus sp. (Eulophidae), represented 25.43, 16.38, 25.43, 19.62 and 13.14% of the total collected hyperparasitoids, successively. The fluctuations of the total parasitoidism percentages recorded one and two peaks of activity during the first and second seasons, respectively. The mean percentages of parasitoidism during the second season was relatively low, 17.65 % in comparison with that in the first one (21.67%). The correlations between the total numbers of aphidophagous syrphid species and percentages of parasitodism were positive significant during two successive seasons. The periodic mean temperature and relative humidity affected syrphid species population by 55.27 and 62.57% during the 1st and 2nd seasons, respectively. Temperature and relative humidity affected percentages of parasitodism by 51.19 and 47.34 during the 1st and 2nd seasons, consecutively. Generally, the pesticides are not the only ones that affect on aphidophagous syrphid predators but the hyperparasitoids decrease the total numbers of the predators and negatively or harmfully affect their role in the biological control of aphid species in open felids and greenhouses | ||||
| Keywords | ||||
| Aphidophagous syrphid predators; parasitoidism; Syrphid hyperparasitoids; biological control; maize plants | ||||
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