Farmers and gardeners determined to protect their plants from slugs and snails may not have to look any further than their morning cup of coffee for an environmentally friendly pesticide.

The menacing molluscs hate caffeine.

Even very small concentrations can be deadly for the garden pests, scientists from the US Pacific Basin Agriculture Research Center in Hilo, Hawaii said on Wednesday.

The stimulant that helps million of people wake up and face the day becomes a deadly neurotoxin when it is sprayed on the slimy creatures.

“It has potential as an environmentally acceptable alternative toxicant for the control of slugs and snails on food crops,” Richard Hollingsworth said in a report in the science journal Nature.

The scientists at the US Department of Agriculture’s research center were testing the effects of caffeine on other pests in Hawaii when they discovered that slugs and snails could not tolerate it.

“We found that large slugs placed on loose soil and sprayed with a one or two percent solution of caffeine responded with uncoordinated writhing; the only survivors were the few that were able to burrow into the soil soon after treatment,” Hollingsworth added.

The weak solution of caffeine didn’t damage the foliage of palms or orchids and any yellowing of leaves could be avoided by mixing caffeine with an appropriate agricultural polymer, he added.