Agriculture Reference
In-Depth Information
8
Arthropod Diversity and Pest
Suppression in Agricultural
Landscapes
Douglas A. Landis and Stuart H. Gage
Research at the Kellogg Biological Station Long-Term Ecological Research site
(KBS LTER) is focused on understanding the ecological interactions underlying
the productivity of row-crop ecosystems. Within these systems, insect pests and
weeds represent two major groups of organisms that farmers must consistently and
effectively manage. Since its inception in 1989, entomologists associated with KBS
LTER have sought to develop a better understanding of the ecology of beneficial
insects and the crop pests they control within agricultural landscapes. As a group,
we have specifically focused on key taxa involved in pest suppression, namely,
predators and parasitoids of insect herbivores and predators of weed seeds. The
long-term goal of this work has been to inform agricultural practices that might
enhance natural pest suppression and thus reduce the need for chemical pest con-
trols. Working toward this goal has involved long-term observations coupled with
shorter-term, hypothesis-driven experiments. This combination has proven a fruit-
ful model for advancing science at KBS and the LTER Network in general (Knapp
et al. 2012).
Shifting Systems of Pest Management
For millennia, farmers have battled with weeds and insects to avoid crop losses.
During the first half of the twentieth century, U.S. row-crop farmers primarily relied
on natural enemies (predators and parasitoids of herbivores), cultural practices
(e.g., tillage, rotation, variety selection), and a limited number of inorganic insec-
ticides to help control insect pests. As a result, literature from that time is full of
careful observations on the biology and ecology of both crop pests and their natural
enemies. However, following the discovery of organochlorine insecticides during
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