Effects of herbicide‐treated host plants on the development of Mamestra brassicae L. caterpillars

• Published in: Environmental toxicology and chemistry 2014-11, Vol.33 (11), p.2633-2638
• Main Authors: Hahn, Melanie, Geisthardt, Martin, Brühl, Carsten A
• Format: Article
• Language: English
• Subjects: Agricultural land; Agrochemicals; Animals; Biological and medical sciences; Brasses; Brassica; Caterpillars; chemistry; Contamination; Ecosystem; edge effects; Farmlands; Flowers & plants; food plants; Foods; Fundamental and applied biological sciences. Psychology; Glycine - analogs & derivatives; Glycine - analysis; Glyphosate; habitats; Herbicide; Herbicides; Herbicides - analysis; Herbivores; Herbivory; Host plants; insect larvae; Insecta; Invertebrates; Landscapes; Larva - drug effects; Larvae; Lepidoptera; Mamestra brassicae; Metabolites; Moths; Nutritive value; Pesticides; Plant defense; Plant species; Plantago lanceolata; Plants - drug effects; pupation; Ranunculus acris; Risk; Risk assessment; Secondary metabolites; Species Specificity; sulfonylurea herbicides
• ISSN: 0730-7268; 1552-8618
• DOI: 10.1002/etc.2726

Herbicides are widely used pesticides that affect plants by changing their chemistry. In doing so, herbicides might also influence the quality of plants as food for herbivores. To study the effects of herbicides on host plant quality, 3 plant species (Plantago lanceolata L., P. major L., and Ranunculus acris L.) were treated with sublethal rates of either a sulfonylurea (Atlantis WG, Bayer CropScience) or a glyphosate (Roundup LB Plus, Monsanto) herbicide, and the development of caterpillars of the cabbage moth Mamestra brassicae L. that fed on these plants was observed. Of the 6 tested plant–herbicide combinations, 1 combination (R. acris + sulfonylurea herbicide) resulted in significantly lower caterpillar weight, increased time to pupation, and increased overall development time compared with larvae that were fed unsprayed plants. These results might be caused by a lower nutritional value of these host plants or increased concentrations of secondary metabolites that are involved in plant defense. The results of the present and other studies suggest potential risks to herbivores that feed on host plants treated with sublethal rates of herbicides. However, as the effects of herbicides on host plant quality appear to be species‐specific and as there are numerous plant–herbicide–herbivore relationships in agricultural landscapes, a general reduction in herbicide contamination of nontarget habitats (e.g., field margins) might mitigate the negative effects of herbicides on host plant quality. Environ Toxicol Chem 2014;33:2633–2638. © 2014 SETAC