Environmental Entomology (2009) 38, 944-954
Ramon Albajes, Belén Lumbierres and Xavier Pons (2009)
Responsiveness of arthropod herbivores and their natural enemies to modified weed management in corn
Environmental Entomology 38 (3), 944-954
Abstract: Alteration of weed flora as consequence of the deployment of genetically modified herbicide-tolerant crops may affect higher trophic levels in agrosystems. A 4-yr study is being conducted in Spain to investigate interrelations between weeds and associated arthropods in corn fields. In a first step, the work aimed to detect the most responsive arthropods to weed management changes. To identify the most responsive arthropods, arthropod composition and abundance in herbicide-tolerant corn plots treated twice with glyphosate and untreated plots were compared for 2 yr. Plots were sampled seven times during the season by visual inspection and pitfall and yellow sticky traps to estimate abundance and activity of the main arthropod herbivores, predators, and parasitoids. As intended, the abundance and composition of weed flora was strongly altered by the differential herbicide treatments. Several groups of arthropods responded to the weed changes but in variable directions. Whereas leafhoppers and aphids were more abundant on herbicide-treated plots, the contrary was found for phytophagous thrips. Among predators, Orius sp., spiders, and trombidids were more abundant on treated plots, whereas nabids and carabids were more abundant in untreated plots; the same case was found for carabids and spiders caught in pitfall traps. Among parasitoids, ichneumonids were more abundant in untreated plots and mymarids in treated plots. These results cannot be interpreted in terms of nontarget effects of postemergence treatments with broad-spectrum herbicides; for this, a comparison with conventional weed management practices should be done and this is the current step in the study.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Ramon Albajes, Xavier Pons
Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
surveys/sampling/distribution
Research topic(s) for beneficials or antagonists:
surveys/distribution/isolation
environment/habitat manipulation
