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Boletín de la AeE

Boletín de la Asociación española de Entomología

 
inglés
Posters | Boln. Asoc. esp. Ent. 21 (Supl.): 127-128 | 1997
Spatial and temporal parasitoid composition in populations of Myzus nicotianae Blackman in Greece
N. Kavallieratos, D. Lykouressis, G. Papadopoulos & A. Vracha
ABSTRACT
Parasitoid composition in populations of Myzus nicotianae Blackman was studied in two different áreas, located at the western (Agrinio) and eastern (Tithorea) part of central Greece, for the tobáceo growing season in 1995 and 1996.

In 1995, samples were taken from several tobáceo fields from the aforementioned áreas at 10 day intervals. In 1996, samples were taken from two tobáceo fíelds, one located in the área of Agrinio and the other in Tithorea, every 10 days. Twenty leaves were collected at each sampling date, 10 from the upper and 10 from the lower half of tobáceo plants except at the first and last sampling when leaves from the lower half were not taken. In Agrinio, sampling commenced on July 4 and lasted till September 5. In Tithorea, the first samples were taken on June 10 and the last ones on September 12.

Leaves were kept separately, live aphids were removed and subsequently identifíed and counted. Aphid mummies were kept individually, with the small leaf peace on which they were stuck, in small plástic boxes for parasidoid emergence and subsequent identifí catión. Also, the rest natural enemies were collected from the samples and stored either in fluid storage or in small boxes depending on the stage and order they were belonged to.

M. nicotianae was only aphid species collected in samples and which developed large populations in both áreas. However, higher aphid populations were found in Agrinio than in Tithorea and peaked at the end of July-beginning of August in 1996

In Agrinio área, the parasitoid spectrum was composed by species in the genus Aphidins, Diaeretielía, Lysiphlebus and Praon. In Tithorea, the parasitoids found belonged to the genus Aphidius and Praon. Generally a higher number of mummies were found on leaves from the lower half than on íeaves from the upper of the plants, in both áreas, through the growing season.

In Agrinio área, the largest proportion of parasitoids emerged were of the genus Aphidius followed by Diaeretielía whilst Praon appeared in even lower proportion. In contrast, in Tithorea almost the whole population of parasitoids during the growing season were of the genus Praon, with the exception of a few individuals which belonged to Aphidius. Since the tobáceo variety in question was the same in the two fíelds, other factors might be responsible for the different parasitoid composition found between the two áreas whích have to be investigated.

Parasitoids were the most significant mortality factor for M. nicoíianae populations in Agrinio because of the high parasitization rates. This was not the case in Tithorea where low rates of parasitization of M. nicoíianae were recorded.
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