Plant identity, but not diversity, and agroecosystem characteristics affect the occurrence of M. robertsii in an organic cropping system

Publication date: Available online 5 June 2018 Source:Biological Control Author(s): Puneet K. Randhawa, Christina Mullen, Mary Barbercheck Organic farmers rely largely on cultural practices, such as crop rotation and cover cropping, and on biological control to manage pests. Winter cover crops add diversity to agroecosystems and can benefit soil conservation and health, retention and supply of soil nutrients, regulation of arthropods, and crop yields. Within the framework of a three-year experiment to investigate ecosystem services and disservices associated with 12 winter cover crop treatments during the transition of a small grain - corn - soybean production system to organic management, we examined the effects of cash crop and crop management, cover crop species and diversity, arthropods, and soil properties on Metarhizium spp. in a single field site in central Pennsylvania, USA. We used sentinel insect assays with Galleria mellonella L. to determine the relative occurrence of Metarhizium spp. in soil samples from treatment plots. M. robertsii was the only species detected, and therefore Metarhizium species diversity was not related to cover crop diversity. Detection of M. robertsii was lower in cover crop monocultures and mixtures containing brassicas compared to those with legumes. M. robertsii was detected more frequently in the standing cover crops in the corn phase of the rotation than in the soybean phase, but there was no difference in soil samples in the corn ...

Source: Biological Control - June 6, 2018 Category: Biology Source Type: research