2.6. Cage design
All cages consisted of 1 m 3 PVC frames with mesh enclosures that varied in the size of the mesh on the sides of the cage.
The predator exclusion cage was made entirely of no-see-um netting (Venture Textiles, Braintree, MA).
The medium- and large-mesh cages had no-see-um netting roofs and cage sides made from either 2 mm mesh (medium-mesh treatment) or 6 mm mesh (large-mesh treatment) (US Netting, Erie, PA).
All cages were lined at their base with Velcro attached to a plastic barrier buried
to secure the cages at the soil surface and prevent entry of ground-dwelling predators.
The cages were arranged in a completely randomized design with three replicates of
each treatment in a soybean field planted in 38.1 cm rows with soybean variety 92B16 (Pioneer Hi-Bred Interna-tional Inc., Johnston, IA) at the Entomology Research
Farm at Michigan State University (East Lansing, MI).
Each cage contained two rows of plants, with an average of 25.3 plants per cage.
When the cages were established aphid density averaged 22.2 per plant. All predators were hand-removed from caged plants prior to beginning the experiment.