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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|
|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|
|University in which they received their degree: ||Kuvempu University, Shimoga|
|Degree Level: ||M.Sc|
|Appears in Collections:||DIVISION OF ENTOMOLOGY & NEMATOLOGY|
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