[pic]3.1. UdL Impact of glyphosate use on arthropods in transgenic herbicide-tolerant .http://www.ncbi.nlm.nih.gov/pubmed/19508806
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Responsiveness of arthropod herbivores and their natural enemies to modified weed management in corn.
AlbajesR, Lumbierres B, Pons X.. Centre UdL-IRTA, Universitat de Lleida,. (Abstract)
Alteration of weed flora as consequence of the deployment of genetically modified herbicide-tolerant crops may affect higher trophiclevels 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 themost 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 anduntreated 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 mainarthropod 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 respondedto 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, Oriussp., 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 pitfalltraps. 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...