The owner of a Te Puke orchard has admitted observing "red angular spotting" on leaves, but not identifying it as the PSA disease in 2010.
Kairanga Orchard manager Graeme Crawshaw is expected to spend most of Wednesday on the witness stand in the High Court at Wellington, as part of a class action by 212 kiwifruit growers.
The case alleges the Ministry for Primary Industries was negligent when the vine-killing disease broke out, costing the industry hundreds of millions of dollars.
Mr Crawshaw's orchard is considered "ground zero" for the vine-killing Pseudomonas syringae pv. actinidiae.
He told the court he did not think PSA was a threat to New Zealand when it had been reported overseas.
"I had seen some red angular spotting (on leaves in his orchard) in October 2010, but thought it was wind damage. Spots on leaves comes and go and I wasn't concerned."
When a representative from kiwifruit marketer Zespri visited a month later, PSA was seen in several kiwifruit bays, he said.
Mr Crawshaw was questioned about his operation using Kiwi Pollen, which allegedly received a PSA-infected shipment from China.
He said it was a shock to be told he had PSA present at his orchard, but said questions about the pollen would have to be put to his wife, Jill Hamlyn, who ran the pollen importing business.
MPI denies all the claims, including that it has a duty of care.
The trial is expected to run for another 10 weeks.