Adapted from an article by MANABU AOIKE in THE ASAHI SHIMBUN. 10/24/2006
AOMORI--A sense of panic set in after the hidden enemy had advanced further north than expected.
The attackers had already left a trail of physical and financial destruction from Nagasaki in the south, and were closing in on the border between Akita and Aomori prefectures on July 7.
"It's another 250 meters," an Aomori prefectural official was warned.
The enemy was the pinewood nematode, a diminutive worm native to North America that causes "pine wilt."
Pinewood nematodes travel from conifer to conifer via pine sawyer beetles (Monochamus), which feed on the pine bark and lay eggs.
The nematodes infest the host tree through the wounds caused by the beetles' feeding. The worms multiply rapidly inside the resin canals that run along the trunk, causing the tree to wilt and die.
The 2-cm-long sawyer beetle can travel a distance of about 2 kilometers a year, making for a slow, but steady path of destruction of pine forests in Japan.
According to the Forestry Agency, the first incident of pine wilt caused by the worms was in Nagasaki in 1905.
The beetles and worms moved north, causing widespread damage to forests in the Hokuriku, Chubu, Kanto and Tohoku regions in the 1970s and 1980s.
The damage affected a number of famous tourist destinations. Amanohashidate in Kyoto Prefecture, and Matsushima in Miyagi Prefecture, considered two of the country's top three coastal scenic spots, (the third being Miyajima in Hiroshima Prefecture) fell victim to the nematodes.
It was only in 1971 that the pinewood nematode was identified as the cause of pine wilt.
After a century since the Nagasaki incident, the only areas that are infection-free are Hokkaido and Aomori Prefecture.
In the summer, Akita prefectural officials warned their neighboring counterparts in Aomori that diseased pine was found only 250 meters from the border.
Until then, the northern limit of devastation by the pinewood nematodes was 4 kilometers south of the border.
Devastation from pine wilt was confirmed in Akita Prefecture in 1982, meaning it has taken 24 years for the worms to advance so close to Aomori Prefecture. Researchers say the slow movement was caused not only by the cold temperatures, but also because of thorough pesticide spraying.
Aerial and land spraying of pesticides is considered effective in eliminating the beetles that carry the nematodes.
But spraying is discouraged on a nationwide basis because of the potentially harmful effects on farming, fishing and health.
The Aomori prefectural government has had no choice but to refrain from using pesticides because of the proximity to important water sources in the targeted area. For example, the Sea of Japan that spreads right before the area is choice fishing ground for hatahata (Japanese sandfish), an Aomori and Akita specialty.
Matsushima, the legendary beauty spot in Miyagi Prefecture that supposedly left haiku poet Matsuo Basho at a loss for words, has been fighting the pinewood nematode for 30 years.
The estimated 4,000 trees that can be seen from sightseeing vessels that cruise the area now get treated with pesticide. A 5-mm hole is drilled into the bark and injected with medication. The treatment costs 8,000 to 10,000 yen per tree.
Miyagi Prefecture budgets about 400 million yen annually for measures to fight the worms.
But such an allocation might not be financially possible for other local governments.
Aomori authorities decided to go with the idea that if there are no pine trees to attract the sawyer beetles, the progression of the nematodes can be contained.
The prefecture came up with a plan to create a "vacuum zone" by chopping down pine forests for a few kilometers along the border. On Sept. 21, the governor inspected the site where trees were being felled.
However, the fight proved a tougher-than-expected battle. The pine forests were denser than estimated. The logging at one area was supposed to have been completed by the end of September, but only 1,600 cubic meters could be cleared, with about 1,000 cubic meters remaining.
In some parts of privately owned forests, owners refused to cut their trees.
Hajime Uchiyama, an official of the Forestry Administration Division of Aomori Prefecture, said the warning from Akita Prefecture about the nematodes created panic among those concerned.
The sawyer beetles--and the destructive worms--still have a route into Aomori Prefecture. Fears about the invaders can only increase.(IHT/Asahi: October 24,2006)
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