The survey found that about half of those who responded had brought back restricted products without having the intention to.Defra said Asian longhorn beetle was an example of an imported pest.
Environment secretary Elizabeth Truss said: "People can be tempted to travel back from their holidays with exotic food or plants, but by doing this they could risk bringing back a disease or pest too."
The survey also revealed few understood the consequences of breaking the rules. Over 70 per cent didn't realise they could face travel delays if they were found carrying restricted products, and almost 20 per cent didn't know that they may have the item confiscated.
Staff at the border often inspect luggage so travellers may be subject to checks on return.