A schoolgirl scientist has discovered the anti-bacterial properties of mānuka honey can be boosted more than 200 per cent by combining it with an extract from the tōtara tree.
Sophia Fotheringham, 18, was the joint overall winner with Tea Rasclas, 17, of the Far North Science and Technology Fair held at the Turner Centre in Kerikeri.
A record of just under 200 projects made the grade for this year's fair, and girls made a clean sweep of the top prizes.
Sophia, who lives in Taipa but goes to Kerikeri High School, said the antibiotic effect of mānuka was well known, but she was curious whether kānuka and tōtara had similar properties because they were also used in traditional Māori medicine.
By creating kānuka and tōtara infusions and testing them on bacteria in agar dishes, on their own and in combination with mānuka honey, she found the mānuka-tōtara mix was 232 per cent more effective than mānuka alone.
More research was needed, but the finding could have practical applications in an era when superbugs and resistance to standard antibiotics were becoming more common, Sophia said.
Sharing the Year 11-13 and overall prizes was Tea Rasclas, who studied alternative methods for controlling the varroa bee mite.
The Kerikeri High student found that placing a cloth soaked in naturally occurring oxalic acid in the beehive was both effective against the mite and safe for the bees.
Tea is keen to pursue as career as a vet, while Sophia wants to study health sciences.
Two of this year's premier awards went to home-schooled sisters Anika and Zara Riddle of Peria.
Anika, 11, who won the Year 7 prize, was sick of clambering down a steep river bank with a 15kg pump to fill the family farm's stock water troughs.
She wanted to be able to leave the pump at the top of the bank and suck the water up instead, so she carried out a series of experiment to see how high the pump could draw water. She now only has to climb down the bank to within 4m of the river.
Zara, 13, won the Year 9-10 section for establishing that Alicante and Dalmatian oxheart are the most productive varieties of tomato plant, a finding which will be put to use in her family's vegetable plot.
Kerikeri High student Lucy Clent, 12, won the top Year 8 prize for a study of the town's Wairoa Stream, using water clarity and identifying macroinvertebrate species (i.e. bugs) to gauge water quality.
Convenor Jackie Robertson, head of science at Kerikeri High, said as well as a record number of entries overall this year's fair included a record 17 senior entries, well up on the previous maximum of 10.
New sponsors had also come on board, expanding the number of prizes on offer.
Robertson said interest in the fair, and the number of girls excelling in science and technology, was "very encouraging".
"Tall poppy syndrome is not a problem in the North. All the students are very proud of their achievements.''
Other projects examined everything from the alcohol content of kombucha to a study of peripheral vision called "Do parents have eyes in the back of their heads?"
The August 30 prizegiving also featured a talk by the Tradescantia Terminators, a group of Kerikeri High students who successfully used biological control against an invasive weed along Wairoa Stream.
The teens' work started as a science fair project but ended up winning them third place in the World Community Problem Solving Championships in the US earlier this year.