PLAGUED by insects? Then slap on some tomato extract: it鈥檚 just as effective as many of the bug repellents used today, and much less of an irritant.
As every hiker knows, modern insect repellents aren鈥檛 exactly user friendly. Chemicals such as DEET work well enough, but in high concentrations the noxious fluid can irritate the skin or even dissolve plastic in clothing, tents and sleeping bags.
This is where Michael Roe, an entomologist from North Carolina State University, reckons tomato plants can help. Roe was studying a protein that kills mosquito larvae when he realised that key features of the protein鈥檚 structure bore a striking resemblance to that of a lipid molecule found in tomato plant stems鈥攐ne that he and colleague George Kennedy had studied earlier. So Roe wondered if the tomato lipid might repel adult mosquitoes.
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It did. In fact, it worked so well that he鈥檚 patenting the idea, and last week Alan Brandt of the company Insect Biotechnology in Durham, North Carolina, last week took out a licence on Roe鈥檚 technology. Brandt says the tomato extract fends off bugs like mosquitoes just as well as DEET.
The new compound works much better than the other non-toxic repellents on the market such as citronella. And unlike citronella, the tomato extract also works against ticks, which carry Lyme disease. But Roe doesn鈥檛 yet know why the compound stops bugs biting.
Bill Bowers, an expert in repellents at the University of Arizona, is impressed with the tomato extract idea. 鈥淚t is timely to replace DEET as it has many toxic effects. Bully for Roe and Kennedy,鈥� he says.