|Schmidt, Nicholas - IOWA STATE UNIVERSITY|
|O'Neal, Matthew - IOWA STATE UNIVERSITY|
Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 10, 2006
Publication Date: October 2, 2006
Citation: Prasifka, J.R., Schmidt, N.P., Kohler, K.A., O'Neal, M.E., Hellmich II, R.L., Singer, J.W. 2006. Effects of living mulches on predator abundance and sentinel prey in a corn-soybean-forage rotation. Environmental Entomology. 35(5):1423-1431. Interpretive Summary: Within a more profitable main crop, other plants may be present to control weeds or erosion. When such plants are not killed, but allowed to grow along with the main crop, they may be referred to as living mulches. Living mulches often appear to increase the number or effectiveness of beneficial insects or other predators, such as spiders. Alfalfa and kura clover were tested as living mulches as part of a rotation with corn and soybean to examine their possible benefits to pest management. When corn and soybean were grown with living mulches, more predators were collected, and more artificially-introduced pests (European corn borer pupae) were fed upon. The increased feeding on corn borer pupae appeared to be linked to the number of predatory ground beetles in plots. This information is relevant to researchers in crop production or growers considering adding living mulches or other cover crops to the production of their main crops. The results suggest that it is important to consider improved control of some pests as one of the possible benefits to growing crops with living mulches. However, the potential benefits of living mulches to pest control are not considered a stand-alone solution to pest control needs. This information is useful for all stakeholders interested in developing methods for sustainable agriculture.
Technical Abstract: Living mulches are cover crops grown concurrently within main crops for their benefits to weed control and soil quality. Because living mulches increase the diversity of vegetation in agricultural systems, they may impact the abundance or effectiveness of natural enemies. To examine the effects of living mulches on epigeal arthropods, predator abundance and feeding were examined in a rotation of corn, soybean, and forage crops in 2004 and 2005. Compared to a no mulch control, the presence of alfalfa and kura clover mulches in corn and soybean increased predator abundance and consumption of European corn borer (Ostrinia nubilalis) pupae used as sentinel prey. A complementary effect of increased predation caused by corn and soybean was found when both annual crops with living mulches were compared to mulches grown alone. Positive correlations between the percentage of O. nubilalis pupae preyed upon and ground beetle (Coleoptera: Carabidae) abundance suggest carabids contributed to the differences in predation. In 2005, the abundance of beetles associated with increased predation [Poecilus chalcites and Scarites quadriceps] declined along with the frequency of benefits produced by living mulches. Both changes could be related to delayed herbicidal suppression of the living mulches in 2005, which appeared to homogenize predator community composition within the corn, soybean, and forage plots. Though living mulches alone may not provide sufficient pest suppression, their potential to enhance biological control should be considered along with their other agronomic benefits.