Harris County Precinct 4 began efficacy studies using the Mosquito Assassin as biological control in the field in 2017, which included monitored releases into specific sites. Monitoring and surveillance were conducted via research-grade BG-Sentinel traps.
In the spring of 2019, Harris County Precinct 4 evaluated the Mosquito Assassin at the Houston Museum of Natural Science Cockrell Butterfly Center (CBC) during a semi-controlled study. The existing infrastructure and conditions of the CBC make it an ideal setting for a semi-field efficacy study of the Mosquito Assassin. The objective is to rid the CBC of pest mosquitos, establish a self-sustaining colony of Mosquito Assassins, promote biological control through educational signage, and evaluate the efficacy of Mosquito Assassins in this semi-field setting.
Telge Road at Spring-Cypress Road was widened to address traffic congestion in the area, which required construction of a stormwater detention basin. Inspired by the opportunity, Commissioner R. Jack Cagle directed the Harris County Flood Control District to include a dragonfly habitat as part of the basin design. Precinct 4’s Biological Control Initiative is tasked with incorporating native mosquito predators, specifically dragonflies and damselflies, as well as natural barriers that could deter mosquito breeding in the stormwater detention basin. This unique project features a wetland environment ideal for dragonfly habitat, a wet prairie meadow for pollinators, a wood buffer with trail access to Little Cypress Creek Preserve, and stormwater detention.
Many mosquito breeding grounds occur in water sources, such as swamps, ponds, rainwater-filled containers, and underground storm drains.
Harris County Precinct 4’s Biological Control Initiative and the Houston Arboretum & Nature Center teamed up to use native organisms for natural mosquito control and reduce the need for pesticides.
Meet Our Agents
Belonging to the Mermithidae family, this small roundworm is entomopathogenic—exclusively infecting and killing mosquito larvae before they become biting adults. Although locally isolated and restricted to a handful of semi-permanent bodies of water, they are native to the southern United States. The southern house mosquito (Culex quinquefasciatus), a vector of the West Nile virus, is highly susceptible to the Culex Killer. In addition, Anopheles mosquitoes which can harbor and transmit Malaria are vulnerable to R. culicivorax.
Rootless, aquatic carnivorous plants that grow along the shallow perimeters of still, inland waters prey upon aquatic organisms, such as mosquito larvae, using tiny “bladders” with suction. Bladderworts capture and digest prey when their delicate, hair-like follicles are triggered. This adaptation facilitates its survival in nutrient-scarce environments. Once added to permanent waters, they can assist with mosquito suppression.
Native Mosquito Assassin
Native Mosquito Assassin
The Mosquito Assassin preys upon container-breeding species, including the pugnacious Asian Tiger mosquito (Aedes albopictus) and the Yellow Fever Mosquito (Aedes aegypti), which are both day-biting pest species and vectors for emerging arthropod-borne diseases such as Zika, yellow fever, Chikungunya, and dengue. A locally occurring Mosquito Assassin phenotype was domesticated in 2013 and is used as production stock for laboratory, field studies, and releases. Some of this work is published in the Journal of Insect Science.
Halloween Pennant Dragonfly
Dragonflies and Damselflies
Dragonfly and damselfly larvae feed on mosquito larvae, and adult dragonflies feed on adult mosquitoes, making these insects leading natural predators of disease-spreading mosquitoes. Precinct 4 Biocontrol Initiative’s efforts are directed towards the conservation of healthy fresh-water environments to promote robust dragonfly communities.
This cyclopoid copepod inhabits temperate regions in still, fresh waters such as roadside ditches and ponds. Though considered member of zooplankton, it feeds on mosquito larvae and has proven highly efficient as a biocontrol agent.