You're always supposed to stand far away from food when applying bug¹ spray. That's because many bug repellents contain dangerous chemicals that can make you sick if you eat them by mistake.

Keeping bugs² away from your body, however, is only half the battle of enjoying a relaxing picnic. How are you supposed to keep the bugs away from your food?

 

 

 

Scientists from New Zealand may have a solution. They've made cardboard food cartons coated with a substance called citronella oil, which is extracted from grass.

Perfumes, candles, and some bug repellents already contain the strong-smelling stuff. And past research has shown that bugs avoid the stink⁴ of citronella, along with the smells of other plant extracts, such as garlic and pine needles.

 

 

 

To find the best formula, the researchers first made a bunch of cartons out of cardboard. Then they treated each box with one of five, bug-repelling plant extracts. They also left a few boxes untreated. Finally, they let loose hundreds of red flour beetles.

Over a number of trials, the beetles avoided the citronella-treated boxes more than any of the others. Further tests showed half as many beetles entered the citronella boxes as entered the untreated boxes.

The effect may be promising⁶, but it's not permanent. After about 8 months, the citronella loses its punch. By then, however, the picnic should be long over.

Even though citronella comes from grass, it's not a good idea to coat your food or even your food containers with it just yet. Scientists still have to show that citronella-treated cartons are safe for people.

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