Disclosed and claimed herein is a device and method for generating carbon dioxide as an attractant for biting arthropods in combination with a trap, comprising: a reaction chamber charged with an aqueous acid solution when in use a gas outlet from the reaction chamber connecting between the reaction chamber and the trap a feeder reservoir containing a powder when in use, said powder comprising a bicarbonate salt and means for controllably adding the powder to the reaction chamber whereby carbon dioxide is generated in the reaction chamber, passed through the outlet and into the trap.
