More than 650 acres of maize at Ngeria Prison farm has been invaded by fall armyworm.
Most of the crops at the farm, which is approximately 20km from Eldoret town, have been eaten up by the pests, leaving them emaciated.
The officer in charge of the prison, Mohammed Siomi, said efforts to curb the menace have been futile.
"We have spent Sh400, 000 on chemicals to contain the pests. We have sprayed the whole farm and are going to the second round but there is still no much impact," said Siomi.
Eldoret Main Prison officer in charge Alfred Musila said few acres of their farm had been infested with the pest. "We have 200 acres of land under maize. Around 10 acres is infested by the deadly worm," he said.