A New Zealand honey giant fears a man who raided their hives may have also infected them.
Basil Martin Lawry, 64, stole brood (eggs, larvae and pupae), honey and bees worth more than $2000 from Arataki Honey and Kintail Honey from 2016 through to 2018.
He appeared before Judge Bridget Mackintosh in the Hastings District Court on Tuesday and admitted eight charges of theft.
Arataki Honey's John Walsh said he was relieved Lawry had been brought to account for the theft but was concerned that Arataki hives may have been infected with American foulbrood (AFB) - a highly infectious bee disease - through Lawry.
Arataki Honey describes itself as the number one beekeeping business in the southern hemisphere, with 20,000 hives across New Zealand.
"So while this theft was bad enough, the possibility that he's infected our hives has compounded the problem. We're just really concerned with this kind of behaviour."