Population dynamics of aphids (Homoptera: Aphididae) and beneficial organisms on protected strawberry crop
- Autores: E. Valério, A. Cecílio, António Mexia
- Localización: Boletín de sanidad vegetal. Plagas, ISSN 0213-6910, Vol. 33, Nº 2, 2007, págs. 153-162
- Idioma: inglés
- Enlaces
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Resumen
In protected strawberry crops, aphids are one of the most important pests and can cause serious losses on strawberry production. The knowledge of aphid population dynamics and beneficial organisms is very useful to reduce damage. To study the aphid population dynamics and beneficial organisms, assays were carried out, in two greenhouses, during the years 2002/2003 and 2003/2004, in the west region of Portugal. The protected strawberry crops were submitted to an IPM (Integrated Pest Management) programme. Biological control and cultural control were selected to allow the observation of interactions between aphid populations and beneficial organisms. Aphids and natural enemies were quantified and identified weekly during the crop period. Predators (coccinellids) were released in order to control aphid populations. The aphid species that reached the economic threshold were Aphis gossypii Glover and Aphis ruborum (Börner). A. gossypii reached much higher population levels than other species. Aphis craccivora Koch, Aulacorthum solani (Kaltenbach) and Macrosiphum euphorbiae (Thomas) were also identified. Primary parasitism by the families Aphidiidae and Aphelinidae was observed, as well as parasitism by entomopathogenic fungi. Predator activity (anthocorids, cecidomyiids, coccinellids, chrysopids, spiders and syrphids) was the most efficient in controlling aphid populations. Aphid population levels always reached high values in the two years of assays, especially A. gossypii. Beneficial organisms and cultural control by periodically removal of old leaves, contributed to reduce the pest populations. However, were insufficient to prevent harmful levels on fruits and consequently releases of predators were justified.
