Crop diversity increases predator abundance but not predation on cereal leaf beetles in agricultural landscapes     

Kheirodin  Arash  Cárcamo  Héctor A.  Sharanowski  Barbara J.  Costamagna  Alejandro C. 《Journal of pest science》2022,95(3):1091-1110

The indirect effect of seminatural habitats on pest suppression has been widely studied in agricultural landscapes. By contrast, the role of crop diversity on pest suppression by predators has seldom been explored, particularly using molecular gut-content analysis (MGCA). In addition, differences between early- and late-season effects of landscape complexity on pest control, crucial to ensure season-long control, have received little attention. During 2014 and 2015, we investigated the effect of agricultural landscape complexity and crop diversity on cereal leaf beetle (CLB, Oulema melanoplus) predation early in the season using sentinel egg cards and late in the season by assessing larval predation using MGCA. Early-season CLB egg predation and late-season abundance of Nabis americoferus and coccinellids in wheat fields were positively correlated with amount of woodland habitat in these landscapes. Contrary to our predictions, crop diversity had negative associations with the late-season frequency of larval predation and the abundance of N. americoferus. Predator diversity and the abundance of Hippodamia lady beetles had negative associations with CLB abundance, highlighting the significant contribution of some generalist predators to CLB suppression. Our results suggest that the proportion of woodland and a few major crops (e.g., canola and non-cereal crops), rather than crop diversity, are associated with higher predation at different temporal scales. Overall, our results suggest that a habitat management strategy could be implemented to adjust the crop rotation regime to add the right kind of crop diversity in the landscape to support the natural control of CLB.

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Contrasting effects of host crops and crop diversity on the abundance and parasitism of a specialist herbivore in agricultural landscapes     

Kheirodin  Arash  Cárcamo  Héctor A.  Costamagna  Alejandro C. 《Landscape Ecology》2020,35(5):1073-1087

Landscape Ecology - Landscape complexity affects herbivores in agroecosystems, but consequences on pest control services are variable. Carryover effects of landscape composition in previous years...  相似文献