Pennsylvania State University University Park, Pennsylvania
Insect pests can cause significant damage to crops worldwide, reducing crop quality and yield. Integrated Pest Management (IPM) was introduced to provide an economic framework for management decisions about insect pests. IPM relies upon predators of insects as a first line of defense against pest populations, however, the most effective predators of key pests are often unknown, making it difficult to accommodate them in agricultural systems. In parts of the United States and Canada, potato leafhopper (Empoasca fabae) is a major pest of alfalfa. E. fabae populations are controlled almost exclusively through pesticide use. Previous studies have identified potential predators of E. fabae, but spiders have been largely overlooked.
To understand their population dynamics and response to management, we tracked leafhopper and spider populations during the growing season. We also conducted a manipulative experiment in an alfalfa-orchardgrass field to determine whether spider populations respond positively to increased structural complexity. Using a factorial design, we assessed the impact of two types of vertical structure on spider abundance: strips of sorghum sudangrass and bamboo stakes. Our results have the potential to reveal the value of spiders in controlling potato leafhopper populations. The response of spiders to increased structural diversity may provide insights for boosting spider abundance and pest control in agricultural fields.
