With the northern hemisphere harvest well under way estimates are 19 million trays of Zespri fruit will be harvested from European growers, largely in Italy.
But the volumes are under a burgeoning threat from brown marmorated stink bugs, Psa and a recently discovered fungal infection thought to be related to phytophora rot.
Most Zespri fruit comes from Italy with about 2800ha and 150 growers.
Plans are for European production to continue ramping up by about 400ha of new orchards a year taking the total area to 5000ha by 2024.
New Zealand’s total kiwifruit area comprises 14,200ha with 80% of it in Bay of Plenty.
Zespri’s innovation leader and biosecurity expert Dr Elaine Gould said the stink bug is of particular concern given how well it is established in other fruiting crops in northern Italy.
While kiwifruit is not necessarily the bug’s first choice it is often the first fruit available when the bug emerges after winter.
“There have been fruit losses of 20-30% recorded so it is enough to be a big concern to growers.”
The kiwifruit-growing region of Emilia Romagna has been hit particularly hard, with growers now having to use drop netting around their orchards to try to keep the bug out because insecticide sprays are not wholly effective.
The bug has already laid waste to Italy’s €300 million pear crop and is knocking on the door of its vast apple industry in the nearby region of Trento.
Zespri has contributed to research to better understand the bug’s lifecycle and control options that include pheromone traps, working alongside NZ researchers and Bologna University.
Work is also being done in the bug’s native China, where it is known to have had a big impact on kiwifruit.
Kiwi scientists based in Italy for the summer months have been working closely with their Italian counterparts on various traps and technology to try to better control the bugs.
They include pheromones and an emerging science of biotremology that broadcasts the mating call of the bug, drawing others into traps.
Bug detections in NZ have been scattered but authorities have taken a when-not-if approach to an incursion, such is its ability to survive long distances as a hitch hiker, typically on imported machinery.
NZ is entering the bug’s active summer season and last year four Japanese ships were turned away when Primary Industries Ministry officials found bugs on them.
Meantime, European growers and researchers are also pre-occupied with another threat, Moira disease.
“We are still a bit unsure exactly what it is but it seems to be related to a phytophora type fungal infection caused in part by flood irrigation of the heavier soils they have there,” Gould said.
“We were concerned when we first found it and it triggered a potential biosecurity risk but we now suspect it is related to the conditions there.”
Zespri’s European grower network comprises about 750 families growing fruit on contract and the marketer is now sourcing about 10% of its fruit internationally to retain year-round store presence.
European growers also continue to contend with Psa, identified on orchards there only one season before it was found in NZ in late 2010.
“Overall, I think Psa is being well managed but France does continue to seem to have a particular problem with it. In Italy a lot of plastic covering is used to keep it out. Growers in general are living with it and there has been a lot of investment and extension around it.”
Zespri also recently announced the discovery of almost 2500ha of illegally grown SunGold kiwifruit in China and is working closely with Chinese authorities in an effort to identify and prosecute the offenders.
