"And with the massive earthquake, travel has completely stopped for now."
The fungal disease is soil borne and it causes the spear to rot in the ground, he said.
It is the main disease of asparagus in New Zealand.
Mr Rainey said the soil can be treated with a fungicide.
"But it's too late now the growing season started. And there's no way we're spraying a fungicide over our fields. We'd rather lose out."
A reduction in the profitable life of asparagus fields in New Zealand would just have to be that way for this season at least, he said.
Last season asparagus farm owner George Turney had to send his 44 Vanuatan seasonal workers 6km down the road to stay at the Kawhatau Valley Outdoor Centre.
This came after his workers' accommodation on the farm didn't pass the Rangitikei District Council's building safety criteria.
Last month the new complex was completed and opened in just in time for the new season.
"I was very relieved, I can tell you," Mr Turney said.
The new building has met all the criteria of the building code, he said.
"But because of all the rain the season got off to slow start but I didn't expect this fungal infection would set in as well. I never thought we'd be facing rationing our crop."
The workers come to the Turney farm under the Recognised Seasonal Employer (RSE) programme.
With Mangaweka Asparagus Farm employing up to 44 Vanuatu workers between October and January, some are doing their eighth season with the Turneys this year.
"And the boys' singing is legendary. They really have the most beautiful voices," Mr Turney said.
As well as singing regularly in the small Kawhatau Valley Anglican Church, the workers will sing at the Taihape Christmas Parade and give a special concert in the town as well.