Fitness and life history parameters of <Emphasis Type="Italic">Leptomastix epona</Emphasis> and <Emphasis Type="Italic">Pseudaphycus flavidulus</Emphasis>, two parasitoids of the obscure mealybug <Emphasis Type="Italic">Pseudococcus viburni</Emphasis> |
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Authors: | Filitsa Karamaouna Michael J Copland |
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Institution: | (1) Pesticides’ Control and Phytopharmacy, Benaki Phytopathological Institute, 8 Stefanou Delta str, Athens, Kifissia, 145 61, Greece |
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Abstract: | Fitness and life table parameters of two endoparasitoids of the obscure mealybug Pseudococcus viburni (Signoret), the solitary Leptomastix epona (Walker) and the gregarious Pseudaphycus flavidulus (Brèthes), were examined in relation to temperature and host size with a view to determine the efficacy of the parasitoids
as biocontrol agents of the pest. Three temperature levels (21°C, 26°C and 31°C) and two host sizes classes (small, which
mostly comprised third instar nymphs and large, which consisted of female adults) were studied. The lower developmental threshold
and thermal constant of the host and the parasitoids were found similar so the coincidence of pest and parasitoids is likely.
The rate of development of the parasitoids increased with a linear trend as the temperature increased from 21°C to 31°C. Temperature
had a significant effect on mummification in both parasitoid species and on successful parasitism by P. flavidulus. Host size had a significant effect on the mummification caused by L. epona and on the proportion of the male offspring which emerged as well as on the successful parasitism by P. flavidulus. Life table parameters of the parasitoids were estimated in small and large hosts at 26°C in the laboratory. Both parasitoids
achieved a greater intrinsic rate of natural increase and gross reproductive rate in addition to a shorter generation and
doubling time in large mealybugs compared with small ones. Consequently, large hosts are expected to have a higher impact
on the rise of the parasitoids population and the potential of the parasitoids to control the mealybug population improves
with the increase of host size.
Handling Editor: Torsen Meiners. |
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Keywords: | Biological control Encyrtidae Fitness parameters Hemiptera Host size Hymenoptera Life tables Parasitoid development Pseudococcidae Temperature effect |
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