Teens invent insect repellent
A working insect repellent has been developed by two teens who took a closer look at common plants surrounding us.
Palmerston North Girls’ High School 17-year-olds Zoe Glentworth and Katie Liu began experimenting with ways to stop mosquitos biting for an international school science and technology challenge called CREST, Creative and Innovative Science and Technology projects, at the beginning of 2016.
‘‘Originally, we wanted to cure malaria and zika, at the time zika was big news,’’ Katie said. ‘‘So we wanted to find ways to decrease the amount of mosquitos biting people and therefore decrease the potential for zika.’’
The pair researched plants used in rongoa, Maori traditional healing, and chose kawakawa leaf for testing because of its known insect repellent properties. They then picked two other plants used historically in herbal preparations to ward of insects – lemon eucalyptus and yarrow, a common roadside weed.
Instead of using mosquitos for their tests, they chose house flies, because they are closely related and easier to work with.
They mixed up extracts made from the three plants, and tried different combinations and strengths by spraying them onto the arms of volunteers. The volunteers then put their arms into a cage of flies.
All three plant extracts ‘‘were significantly more effective at repelling the common housefly in comparison to controls’’ of a bare arm or salt solution, they said in their findings.
The repellents seemed to work both in single extracts and combinations.
Zoe and Katie presented their project in the Manawatu Science and Technology Fair in August, where they won the best exhibit in the fair prize for science, and category prizes in statistics, the environment and conservation and native diversity.
Zoe said they planned to continue testing how well the plants work as insect repellent by experimenting to find what the lowest effective dose.