Since the beginning of the project in April 2012, our lab has screened a wide array of plant essential oils for baseline toxicity and in combination with various synthetic pyrethroids against Aedes aegypti, the yellow fever mosquito, and Anopheles gambiae, the African malaria mosquito. To date, we have identified essential oil candidates that enhance the toxicity of various synthetic pyrethroids, and some that cause greater enhancement than the most commonly used commercial synergist in synthetic pyrethroid formulations, piperonyl butoxide (PBO).
It is well established that insects and plants have shared a long evolutionary history with one another. Due to this evolutionary “arms race,” plants have developed some truly fascinating ways to deter insects from feeding upon them, such as production of various terpenoid compounds that repel or kill insect pests. Our lab is interested in isolating plant-derived compounds that may act as natural repellents.
Octopamine and tyramine are essential biogenic amines that have been implicated in numerous physiological systems in arthropod species, such as reproduction, the nervous system, and learning-and-memory, to name a few. We have successfully created two stably-transfected Chinese Hamster Ovary cell lines (CHO) with a functional octopamine receptor from Periplaneta americana, the American cockroach, and a functional tyramine receptor from Rhipicephalus microplus, the southern cattle tick.
We perform various bioassay tests for various companies and agencies to quantify the ability of new insecticidal formulations to kill and repel a wide array of arthropod pest species. Some of the species we utilize in our testing includes, but is not limited too: house flies, cockroaches, ticks, bed bugs, mosquitoes, fleas, crickets, corn rootworms, corn borers, cutworms, aphids, and spider mites. The fees for service, as well as the types of testing to be performed, are negotiated via a contract basis.
Environmental Toxicology and Chemistry
It is important to understand the degradation and persistence of pesticides in soil and water in order to maximize pesticide efficacy while minimizing any detrimental effects they may have on the ecosystem.
Understanding mobility of pesticides is an important part of environmental toxicology and chemistry. Pesticides need to be mobile enough to allow them to be transported to the site of action. On the other hand, pesticides that are too mobile will rapidly dissipate once applied to the target area and contaminate water and sediment. Many factors can affect the mobility of pesticides in soil and water including soil characteristics, pesticide properties, and timing of application.
In recent years, transgenic crops have increased significantly in their usage in agriculture. Many of these crops produce insecticidal Bt proteins that target specific insect pests. As with conventional chemicals, it is important to know the fate of these insecticidal Bt proteins in the environment. The fate data is used in the risk assessment process to determine potential exposure of the insecticidal Bt proteins to non-target organisms.
Extensive pesticide use over several decades has resulted in the contamination of soils and water bodies. Pesticides can either these ecosystems either by intentional application, or incidentally by spray drift, surface water runoff, or spills. These pesticides may have a variety of detrimental effects on aquatic and terrestrial organisms, and could lead to disruption of the ecosystem. Cleaning up contaminated sites by conventional methods, such as excavation and storage off-site, can be expensive and not practical for areas with only minor contamination issues.
Veterinary pharmaceuticals have emerged in recent years as a contaminant of concern in the environment. While not applied to soil and water bodies directly, veterinary pharmaceuticals enter the ecosystem after being excreted by grazing livestock or by the spreading of manue on agricultural fields as fertilizer. As with other chemicals, veterinary pharmaceuticals may have detrimental effects on aquatic and terrestrial organisms, particularly on bacteria where they may contribute to the development of antibiotic resistance.