High rodent or rat populations in urban areas are a consequence of increasing human population density and climate change. Dense human populations create abundant food sources and shelter while rising temperatures are extending the breeding season for rats. The persistence and further expansion of rodent populations pose a multitude of problems. These include public health risks due to disease transmission and food contamination, damage to private and public properties and other shared urban spaces, and lower quality of urban living.
Rodent control in big cities is an ongoing battle. However, in most cases, several efforts have been futile. Enter SenesTech. This agricultural biotechnology and life sciences company headquartered in Phoenix has built its business around pest control. Its main proposition is to control and reduce the rodent population via contraceptives and infertility. The company has developed specific products based on this central objective. It has also commercialized these products by seeking and landing regulatory approvals from relevant government agencies.
How SenesTech Plans to Curb Rodent Populations in Urban Areas With Rat Infestation Problems
Company and Product Background
SenesTech was founded in 2004. It was based on the innovative idea of two female scientists who developed a technology initially designed to induce menopause in mice while pursuing research on the reproductive health of women. The commercial application of this discovery was apparent since it could be used to address rodent populations by controlling fertility.
The company has since introduced two products. The main one is ContraPest. It is a sugary liquid formulated to attract rats and render them infertile when consumed. The active ingredients are 4-vinylcyclohexene diepoxide or VPD, which reduces immature ovum in immature ovarian follicles, and triptolide, which reduces the reproductive capacity of male and female mice.
SenesTech promotes its product as a humane solution for controlling rodent populations. It does not kill nor harm rodents since it is focused on addressing rapid reproduction. The formulation also does not induce permanent infertility in both male and female rats. Their studies have also indicated that it does not impact non-target species or travel up the food chain.
The company introduced a newer product called Evolve in 2023. It is specifically a sub-brand of soft-bait fertility control products with a different formulation. The active ingredient is cottonseed oil. Studies have shown that it can interfere with rodent reproduction. Further tastings also showed it has little to no risk to humans and other non-target animals like dogs and cats.
Applications and Known Limitation
The U.S. Environmental Protection Agency approved ContraPest in August 2016 for commercial use. The regulatory agency also permitted SenesTech to remove the “Restricted Use Only” labeling in October 2018. Evolve has also earned a FRIFRA Section 25(B) exemption status. This means that it is a minimum-risk pesticide that does not require FIFRA registration.
A 2017 study in Norway showed that VPD and triptolide were effective in rendering female rats infertile in the first two breeding cycles but variance in the rate of fertility recovery occurred in the fourth breeding cycle. Another 2020 study revealed that a 58-day feeding period resulted in zero litters in the first two breeding cycles. Fertility recovered in the next breeding cycles.
SenesTech is expanding its global footprint. It signed a distribution agreement with a third-party distributor in India in February 2025 to enter the Indian pest control market. The company has also received regulatory approval in Australia and New Zealand. The New Zealand government has an ongoing multi-billion conservation initiative to eradicate invasive predators like rats.
The company still has to demonstrate the long-term effectiveness of its products and their pivotal selling propositions. The problem with its solution rests on the fact that large urban areas with dense human populations tend to have a large open population of rats with too many food sources to pick from. Fertility-based approaches lack measurable results in urban settings.
FURTHER READINGS AND REFERENCES
- Siers, S., Sugihara, R. T., Leinbach, I., Pyzyna, B. R., and Witmer, G. 2020. “Laboratory Evaluation of the Effectiveness of the Fertility Control Bait ContraPest on Wild-Captured Black Rats.” Proceedings of the Twenty-Ninth Vertebrate Pest Conference. Vertebrate Pest Conference Proceedings. Available via PDF
- Witmer, G. W., Raymond-Whish, S., Moulton, R. S., Pyzyna, B. R., Calloway, E. M., Dyer, C. A., Mayer, L. P., and Hoyer, P. B. 2017. “Compromised Fertility in Free Feeding of Wild-Caught Norway Rats With a Liquid Bait Containing 4- Vinylcyclohexene Diepoxide and Triptolide.” In Journal of Zoo and Wildlife Medicine. 48(1): 80-90. American Association of Zoo Veterinarians. DOI: 1638/2015-0250.1