In August 2015, the first case of potato ‘white’ cyst nematode Globodera pallida (G. pallida) was detected in the Northeastern parts of Hokkaido, Abashiri.
This region in Japan is famous for its starch potato fields and is a contender for being the area where the most potatoes are grown with the highest yield, as well as the largest volume of potatoes are shipped from within Japan. Potato yellow cyst nematode Globodera rostochiensis (G. rostochiensis) was also detected in this region.
Since September 2015, soil inspection and tuber sampling inspection services were launched and implemented repeatedly in the region. The sampling inspection routine is to obtain samples from a potato variety resistant to G. rostochiensis is sampled, and then visually inspect any cysts clinging to roots.
As a result of these inspections, G. pallida was confirmed in 163 fields on 681ha (more than 10% of the inspected fields). Moreover, it’s been confirmed that approximately 10 years have passed since the first G. pallida nematodes first infested the fields.
In September 2016, an emergency control inspection was conducted based on plant protection law. The aim was to ensure complete eradication of this pest. Any transportation and planting of potatoes in the affected area were prohibited.
Since no potato variety resistant to G. pallida had been introduced to Japan, application of 1,3-Dichloropropene and planting cover crops (tomato wild species; Solanum peruvianum L.) were the solutions chosen to ensure eradication of the pest.
In 2018, 1,3-Dichloropropene was applied to 68 fields on 284ha and cover crops were planted in 79 fields on 265 ha. In 28 fields (131ha), the eradication strategy was in essence “twice application of 1,3-Dichloropropene and one cover crop planted”, or “one application of 1,3-Dichloropropene and two cover crops planted in succession”.
1,3-Dichloropropene is not approved in Europe and other countries. Although 1,3-Dichloropropene is approved in Japan, the application of 1,3-Dichloropropene has its challenges, including a safe method of disposal.
Abashiri is a famous fishery city for among others, salmon fishing. Some of the potato fields where G. pallida was detectedare locatednear an important river in this city. In consideration of this, a new method of eradicationis now under consideration.
Granular nematicides – of which Nemathorin (fostiazete) and Nemakick (imicyafos) are available in Japan – are applied to infected fields that are located within 500 meters from the river, instead of the strategy of 1,3-Dichloropropene application in combination with cover crops. In addition, appropriate crop rotations and the introduction of resistant potato varieties are done continuously.
The successful management of PCN has two crucial challenges in Japan, namely to find abalance between complete and efficient eradication of G. pallida and an environmentally responsible way to this, while being done with the understanding and collaboration of all stakeholders involved.
Sources: Press releases, related government regulations, and minutes of a recent review meeting arranged by the Japanese Ministry for Agriculture, Forestry and Fisheries.
Author: Mariko Kihira, owner of the consulting company maru communicate. She can be reached at email@example.com
This article was first published in the February issue of the Global Potato News magazine.