Evaluating Non-Target Effects of Rootworm Maize (Cry34/35ab1) on Carabid Beetles
Corn Insects and Crop Genetics Research
2013 Annual Report
1a.Objectives (from AD-416):
1) Determine whether Cry34/35Ab1 rootworm Bt corn significantly affects the abundance and diversity of carabid beetle populations;.
2)Determine whether insecticide treated soil significantly affects the abundance and diversity of carabid beetle populations;.
3)Assess the magnitude of the effects of Cry34/35Ab1 Bt corn on carabid beetles relative to the effects of soil insecticides.
1b.Approach (from AD-416):
A two year study will investigate possible effects of rootworm Bt (Cry34/35Ab1) corn on carabid beetles. Corn hybrids will include Roundup Ready Cry34/35Ab1 corn, known as Herculex (R) RW [HR-RW], and a non-Bt near isoline [NBt-Iso]. Insecticides would include seed treatments Poncho 1250, Cruiser 250, and tefluthrin applied once at planting. The following treatments will be arranged in a RCB and replicated four times: .
1)HR-RW (no insecticide);.
2)NBt-Iso (check, no insecticide);.
3)HR-RW with Poncho 1250;.
4)NBt-Iso with Poncho 1250;.
5)HR-RW with Cruiser 250 + tefluthrin; and.
6)NBt-Iso with Cruiser 250 + tefluthrin. Pitfall traps will be used to sample beetles ten times over each growing season.
Two years of field tests have been completed to determine possible non-target effects of maize with resistance to rootworm (Bacillus thuringiensis binary proteins Cry34Ab1/Cry35Ab1) on ground beetles. Processing of the pitfall traps is complete and analysis of the data continues. Univariate and multivariate approaches are being used to examine the effects of the treatments on beetle population dynamics.