The scent of flowers draws bees and butterflies. The beautiful scenery of nature has opened a way to eliminate an unwelcome visitor that takes hundreds of thousands of lives every year. Scientists have found a fungus that lures mosquitoes with floral scents and kills them. It is harmless to humans and easy to culture, and is expected to greatly help mosquito control in underdeveloped regions.
A joint team led by Raymond J. St. Leger, a distinguished professor in the Department of Entomology at the University of Maryland, and Weiguo Fang, a professor in the School of Life Sciences at Zhejiang University, said on the 25th that they "developed a Metarhizium fungal strain that mimics the sweet scent of flowers to lure mosquitoes that feed on human blood to their death," in the journal Nature Microbiology. The Health Sciences Research Institute in Burkina Faso also took part in the study.
◇ First discovery that a fungus's floral scent attracts mosquitoes
Mosquitoes also seek flowers like bees and butterflies. St. Leger said, "Mosquitoes are drawn to the scent emitted by flowers, which provide nectar as an important food source," and noted, "We got a hint for mosquito control from the fact that some fungi can trick mosquitoes into mistaking them for flowers."
Metarhizium fungi live on insect corpses and produce longifolene, a volatile compound that emits a sweet, flower-like scent. Other insects flock to this scent. The fungal spores are easily transferred to insects and use them as food.
The team identified olfactory receptors that bind to longifolene in the fruit fly (Drosophila melanogaster) and the Asian tiger mosquito (Aedes albopictus). The Asian tiger mosquito transmits viral diseases such as Zika, dengue, chikungunya, and yellow fever. The researchers said this is the first time it has been shown that longifolene attracts mosquitoes.
The team modified the genes of Metarhizium to produce more longifolene. Then more mosquitoes gathered. Even in rooms with actual flowers that entice mosquitoes and with people present, the fungus's longifolene attracted mosquitoes and killed 90% to 100% of them. Longifolene is harmless to humans. St. Leger said, "Longifolene is already widely used in perfumes."
◇ Mosquito-killing fungus produced from agricultural byproducts
According to the World Health Organization (WHO), more than 700,000 people die each year from diseases spread by mosquitoes. Of these, about 600,000 are malaria victims. Various insecticides have been developed to date, and even gene-editing technologies that eliminate mosquito reproductive functions have emerged, but humans still have not beaten mosquitoes. Mosquito-borne diseases occur mainly in underdeveloped countries in Africa, Asia, and South America, where a lack of medical infrastructure prevents effective control.
The researchers said the fungus developed this time can be produced easily and cheaply, and could become a key tool to reduce mortality from mosquito-borne diseases, especially in poor countries in the Southern Hemisphere. Metarhizium fungi are already cultured worldwide using low-cost materials such as chicken manure, rice bran, and straw, and are used for pest control against termites, weevils, and thrips.
St. Leger explained, "A flower-scented fungus is easy to use as a mosquito control tool and requires little specialized training or expertise." The team said that whether indoors or outdoors, once spores are placed in a container, longifolene is released immediately and remains effective for months. When mosquitoes contact the spores, they become infected and die within a few days.
They also said there is no concern about disrupting ecosystems. St. Leger said, "Longifolene is much safer than chemical insecticides and breaks down easily in nature," adding, "In particular, we developed a fungal strain that produces longifolene targeting only mosquitoes." That means there is no problem for humans or for bees and butterflies that help pollination.
The team said it will track whether mosquitoes evolve to avoid the fungus. St. Leger said, "Mosquitoes need flowers to survive, so it will be hard for them to avoid the floral scent produced by the fungus," and added, "If mosquitoes evolve to avoid longifolene, we can immediately improve the fungus to produce other floral scents."
References
Nature Microbiology (2025), DOI: https://doi.org/10.1038/s41564-025-02155-9