ECOLOGICAL STUDIES ON NATURAL ENEMIES ASSOCIATED WITH APHIDS ON ALFALFA CROP AT FAYOUM GOVERNORATE, EGYPT. | ||||
| Fayoum Journal of Agricultural Research and Development | ||||
| Article 1, Volume 31, Issue 1, January 2017, Page 1-14 PDF (1.79 MB) | ||||
| Document Type: Research articles. | ||||
| DOI: 10.21608/fjard.2017.191226 | ||||
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| Author | ||||
| Rabei H. A. Solaiman | ||||
| Department of plant protection, Faculty of Agriculture, Fayoum Univ., Egypt. | ||||
| Abstract | ||||
| The presnt study was carried out during 2012/2013 and 2013/2014 alfalfa seasons. The aphid species, Aphis craccivora Koch, Therioaphis trifolii Mon. and Acyrthosiphon pisum Harris were found in both study seasons, A. craccivora and T. trifolii were prevalent. The dominant predators were Coccinella undecimpunctata L. reaching 32.3% of predators population in the first season, Chrysopa carnea Stephens and Orius sp. which reached 80.1% in the 2nd season. Aphid fungal infection rate (8.4 to 8.7%) was higher than the rate of aphids parasitized (3.6 to 6.1%).The total death occurred by parasitism and fungal infection ranged from 12.3 to 14.5 % of the total collected aphids. C. undecimpunctata had 5 peaks per season with highest peaks in the 1st week. and last week of Dec for both study seasons, respectively.The highest peak of C. carnea was recorded in the 2nd week of April, while the highest population density of Orius sp. was in spring. Aphid parasitism occurred during two periods of activity in both seasons. The highest peaks of fungal infection were 8.67 and 10.0 infected individuals / 10 stems of alfalfa in the 2nd and 4th weeks of Dec. The results obtained from this study showed that fungal infected aphid and C. undecimpunctata population were positively correlated with aphid population and %RH, while they negatively correlated with mean temperature. | ||||
| Keywords | ||||
| Alfalfa; Aphids; fungal infection; parasitoids; predators; population fluctuations | ||||
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