The role of carbon dioxide as an orientation cue for western corn rootworm larvae within the maize root system: implications for an attract‐and‐kill approach

BACKGROUND Western corn rootworm larvae use CO 2 to locate maize roots. However, the importance of CO 2 as a specific orientation cue close to maize roots has not been investigated unequivocally. This study aimed at elucidating the effect of CO 2 ‐emitting capsules in combination with a soil insecticide (Tefluthrin = attract and kill) within the root system. We hypothesized that the capsules would result in aggregation of the larvae at the soil insecticide, thus increasing its efficacy. A nondestructive observation device was used to study larval distribution and behaviour.RESULTS Spatial analysis of distance indices ( SADIE ) revealed aggregation of the larvae around the capsules in an attract‐and‐kill treatment after 4 h, which was not found with the conventional treatment without the capsules. However, larval mortality did not differ between treatments.CONCLUSION CO 2 is a weak attractant for western corn rootworm larvae within the root system. Consequently, an attract‐and‐kill strategy based on a CO 2 product will not contribute to better control compared with conventional Tefluthrin applications. Host‐specific compounds, combined with a CO 2 source, should be used to target more larvae, making attract and kill a feasible management option against this pest. © 2013 Society of Chemical Industry