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Title: Bio-ecology, population dynamics, pest-predator-ant interactions with reference to the aphid, Aphis punicae Passerini in pomegranate ecosystem
Authors: K, Sreedevi
Guide/Chairperson: Abraham Verghese
Keywords: Bio-ecology
Aphis punicae
Issue Date: 2003
Year of Submission: 2003
Abstract: Studies on "Bio-ecology, population dynamics and prey-predator-ant interaction with special reference to pomegranate aphid, Aphis punicae Passerini" were carried out during 2000-2003 at the Division of Entomology and Nematology, Indian Institute of Horticultural Research, Hessaraghatta Lake - PO, Bangalore (12˚58'N; 77˚35'E), India. The major conclusion drawn from the present study were - The aphid, A. punicae has 4 nymphal instars of duration 1 – 1.5 days each. Thus total nymphal duration was found to be 4 – 5 days and adult longevity ranged from 2 – 8 days. Total life cycle was observed to range from 6 to 13 days. The seasonal incidence of A. punicae has shown two peak periods. A major peak during January – February and a minor one during July – June were observed. Predators were found in abundance during both the peaks and showed numerical response to its prey, A. punicae The fungus, E. aphidis was found to occur in epizootic form on aphids. The ants were not associated with aphid during January – March, however, they were found associated during July – September. The crop phenology factors that influenced aphid population the most were tender shoots, which favoured the aphid multiplication while the full matured leaves and medium to large fruits that did not favour the population build up. Predators were also negatively correlated with the full matured leaves. Ants were positively related with full matured leaves and negatively with tender shoots showing just opposite relationship with what aphids showed. Among meteorological factors, the relative humidity and minimum temperature showed negative influence on A. punicae population. However, predators were not influenced by weather parameters, once again confirming that they were prey- dependent. Ants were positively related to the wind speed and temperature. The aphid infestation had negative impact on fruit size and development. Among different predators, C. sexmaculata was found to be the most abundant species followed by Scymnus on A. punicae in pomegranate ecosystem. Prediction models were developed for A. punicae with three independent variables viz., tender shoot, relative humidity and minimum temperature. These findings can serve as a basis to develop further IPM strategy
URI: http://www.erepo.iihr.ernet.in/handle/123456789/502
University in which they received their degree: Kuvempu University, Shimoga
Degree Level: M.Sc

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