"If successful, the technique could be used by malicious actors to help spread diseases to almost any crop species and devastate harvests," said the paper, which was authored by the French and German researchers including geneticist Robert Guy Reeves of the Max Planck Institute for Evolutionary Biology in Germany and evolutionary biologist Christophe Boete of the Institute of Research for Development in France.
The Defense Advanced Research Projects Agency (DARPA) launched the project, called "Insect Allies," in Arlington, Virginia in 2016, with the goal of using insects such as aphids to infect crops with tailor-made viruses that can deliver certain genes to mature plants, the researchers explained.
The objective, DARPA says, is to find a new way to protect plants from emerging threats. But the researchers said the program could easily be perceived as a covert effort to produce a biological weapon.
"In the context of the stated aims of the DARPA program, it is our opinion that the knowledge to be gained from this program appears very limited in its capacity to enhance US agriculture or respond to national emergencies," they wrote. "As a result, the program may be widely perceived as an effort to develop biological agents for hostile purposes and their means of delivery, which — if true — would constitute a breach of the Biological Weapons Convention."
READ MORE: Moscow Suspects US of Testing Bio Weapons on Russian Border, Warns Washington
DARPA Program Manager for Insect Allies Blake Bextine said in a Thursday statement that he disagrees with the scientists’ opinion.
"I appreciate the thought that went into the critique of the program presented in Science, though I disagree with its conclusions. Technologies dealing with food security and gene editing certainly do have a higher bar than most for transparency, research ethics, and regulatory engagement, and I believe Insect Allies meets that raised standard," Bextine said.
The paper's publication comes amid increasing global concerns about the possible covert development of biological weapons.
READ MORE: Pentagon Denies Developing Biological Weapons at Lugar Center in Georgia
Earlier on Thursday, Russian Maj. Gen. Igor Kirillov, the commander of the Russian Armed Forces' Radiological, Chemical and Biological Defense Troops, accused the United States of carrying out large-scale covert biological warfare research using labs located in Georgia, Ukraine, Azerbaijan, Uzbekistan and elsewhere.
Pentagon spokesperson Eric Pahon denied Kirillov's assertion that one such facility in Georgia, the Lugar Center for Public Health and Research, is being used for the development of biological weapons.