By Stephen Adams
Last Updated: 2:43PM GMT 05 Jan 2009
Jeffrey Lockwood, professor of entomology at Wyoming University and author of Six-legged Soldiers: Using Insects as Weapons of War, said such Rift Valley Fever or other diseases could be transported into a country by a terrorist with a suitcase.
He told BBC Radio 4's Today programme: "I think a small terrorist cell could very easily develop an insect-based weapon."
He said it would "probably be much easier" than developing a nuclear or chemical weapon, arguing: "The raw material is in the back yard."
He continued: "It would be a relatively easy and simple process.
"A few hundred dollars and a plane ticket and you could have a pretty good stab at it."
Governments, he advised, needed to have robust "pest management infrastructure that's able to absorb and respond to an introduction" of infected insects, he said.
Trying to stop everything coming in at the border would not work, he said.
Rift Valley Fever is an east African disease which "can cause severe disease in both animals and humans, leading to high rates of disease and death" according to the World Health Organisation.
However, WHO says that "the vast majority of human infections result from direct or indirect contact with the blood or organs of infected animals."