The present invention relates to an ovitrap (10) and novel method of controlling mosquito populations comprising the use of light (20) to create a photo stimulus, causing mosquito larvae (102) to move from a location (Va), where gravid mosquitoes have deposited their eggs, in a direction away from the light, to a location (Vb), where they are trapped and killed. The ovitrap utilises this behaviour to more effectively capture and kill larvae. The ovitrap comprises a container (12), a cover (14), and a means (16) for dividing the container (12) into two regions (101； 102), which in use are filled with water, and which communicate via an opening (26) such that a volume (Vb) below the means (16) defines a larvae (102) trapping region, and a volume (Va) above the means (16) defines an egg (101) receiving region. A light source (20) is mounted above the container (12) and is positioned to direct light downwards at a water surface (92), such that when the light is turned on, it creates a photo stimulus, and the larvae (102) respond by moving in a direction away from the light, from the volume above (Va) into the volume below (Vb) via opening (26). A gating mechanism (18) opens and closes the opening (26) when the light is respectively turned on and off, such that the larvae are trapped in the volume below and are starved of oxygen and die.
