2014. december 21., vasárnap

Howe et al. (2015) Entomologia Experimentalis et Applicata

Pest suppression by natural enemies is an important ecosystem service, which is a valuable resource
to poor smallholders in developing countries. Diverse natural enemy assemblages of arthropod pre- dators and parasitoids are documented in various regions in Africa, but our knowledge of their impact on herbivores in agroecosystems remains limited.We conducted experiments in cotton, Gossypium hirsutum L. (Malvaceae), under typical local agronomic practices in Uganda to assess levels of predation pressure ascribed to natural enemies.We measured predation rates on artificial caterpillars made of plasticine glued to cotton plants. Predation pressure on cotton fields varied between 1.96 and 4.1% per day, but was not significantly influenced by cotton treatments (insecticide/no insecticide, monocropping/intercropping with Phaseolus spp.). Predation pressure in non-crop habitats adjacent to cotton fields was up to 129 higher than in the fields. Marks left on the artificial caterpillars revealed that arthropods and birds were largely accountable for predation in cotton fields, whereas arthropods and smallmammals were dominant in non-cultivated habitats.

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