About Us

Commissioner R. Jack Cagle established Harris County Precinct 4’s Biological Control Initiative in 2012 to find and develop natural mosquito control methods. Biological control expands the arsenal in the fight against mosquito-borne diseases by using nature against nature and using organisms that prey upon the mosquito. Dedicated technicians and scientists, led by Anita Schiller, research and apply biological controls within Precinct 4.

Mission

The mission of Harris County Precinct 4’s Biological Control Initiative (BCI) is to find, evaluate, develop, produce, and release potential biocontrol agents against pest mosquitoes within Harris County Precinct 4.

When incorporated into pest management programs, biological control enhances the effectiveness of pesticides and can reduce the need for their application. Pesticide and insecticide use can result in unintended ecological consequences that can potentially decimate beneficial invertebrates, including bees and other important pollinators, birds, and fish. Mosquitoes may also develop a resistance to insecticides, thus reducing the effectiveness of future insecticide treatments.

The research and development of a biocontrol agent begins with identifying native organisms that show potential to impact the target without harming non-targets. BCI must also find cost-effective ways to produce the biocontrol agent for deployment in the field. The potential agent is then evaluated in the laboratory as well as semi-field and field settings to ascertain its efficacy to reduce pest mosquito populations.

Internships

Summer internship applications are accepted yearly during the spring.

HCP4 Biological Control Initiative is seeking seasonal (i.e., ~3 months) technicians for the summer season. Start date will be flexible, but availability from early May through mid-August is necessary. This is an hourly position and includes insectary as well as field work.

Summer Intern Job Description

Internship Application

The Process

Step One

Identification

Step Two

Laboratory

Step Three

Semi-Field

Step Four

Field

Projects

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.

Meet Our Agents

Culex Killer

Romanomermis culicivorax

Culex Killer

Romanomermis culicivorax

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.

Carnivorous Plants

Utricularia spp.

Carnivorous Plants

Utricularia spp.

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

Toxorhynchites rutilus

Native Mosquito Assassin

Toxorhynchites rutilus

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

Celithemis eponina

Dragonflies and Damselflies

Odonata

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.

 

Predacious Copepods

Macrocyclops albidus

Predacious Copepods

Macrocyclops albidus

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.