元NIEHSに勤務していたアメリカ人の友人のBuck Grissom 博士から、ニューヨーク州におけるVarroa Mite （ミツバチヘギイタダニ）がミツバチコロニーに及ぼす影響が深刻なことを示した以下の情報が届きました。ミツバチコロニーの元気がない現象は、すぐネオニコチノイド剤の影響（種子処理も含めて）に結び付けられがちですが、国によって、場所によって、巣箱（コロニー）によってVarroa Mite の寄生率による影響をきちんと調査して補正してあるかどうかをチェックしないと、間違った考察を導いてしまいます。
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Subject: PRO/AH/EDR> Varroa mite, Apis - USA: (NY) [EXTERNAL]
VARROA MITE, APIS - USA: (NEW YORK)
A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>
Date: Sun 9 Jul 2017
Source: Newsday [edited]
A plague of parasitic mites is exterminating New York bee colonies,
threatening USD 500 million in losses from the state's annual agricultural
production that relies on bee pollination and honey production.
Commercially operated bee colonies in upstate New York have sustained up to
70 percent population loss over the past several years due to pesticides,
loss of habitat and disease, according to state officials.
But the _Varroa_ mite has recently emerged as one of the leading causes of
colony death in New York, and has infested 90 percent of the colonies
surveyed in the past year, said Emma Mullen, a research scientist at Cornell
University. Mullen is the senior lead of the New York State Beekeeper Tech
Team, a group of scientists working with state officials to protect
honeybees and other species of animals that pollinate crops. "A lot of the
operations that we visited - 78 percent of them - had levels that are
critical for honeybee health," Mullen said. "It poses a risk to the colony
_Varroa_ mites weaken honeybee colonies by feeding off the bees in a manner
similar to a mosquito. Deadly viruses are transmitted to the colony in the
process, which can cascade into an extermination of the colony, according to
Her team was formed just over a year ago with USD 150 000 in state funding
and is led by the Department of Agriculture and Markets. The Department of
Environmental Conservation also collaborates in the state initiative to
protect pollinator species.
"The conundrum here is that everyone realizes that it's significant, we all
need pollination," said Richard Ball, commissioner of the Department of
Agriculture and Markets. "But when we gathered to do the Pollinator
Protection Plan, we began to realize there were huge gaps in the actual
understanding, other than it's a big deal."
Ball said state officials were surprised to find out just how much of a
threat the _Varroa_ mite was when Mullen's team published its findings. Only
36 percent of beekeepers were independently monitoring their colonies for
the parasite in 2016, according to Mullen's report.
Beekeepers on Long Island are hobbyists. Some have established relationships
with local farms, providing farmers with pollination for their crops while
allowing the bees to collect forage to produce honey. Donal Peterson is
among those who closely monitor their hives for _Varroa_. He is vice
president of the Long Island Beekeepers Club and manages 100 bee colonies
across Long Island, with about 4 million bees between them all. "Every one
of them have _Varroa_ to some level, but it's manageable," Peterson, of Bay
Shore, said recently as he collected honey from a hive at Restoration Farm
in Old Bethpage.
"Other beekeepers tell me that they don't have _Varroa_ mites in their
colonies. I just don't think that they know how to look for them."
It's difficult to prevent _Varroa_ mites from infesting a colony in the 1st
place, Peterson said, because it requires that other nearby colonies stay
healthy. When one colony gets sick and dies, other nearby colonies will
attack to steal their honey, which causes the mites to spread even further.
"I've tried it myself as a hobbyist, thinking that I could be a very
hands-off beekeeper," said Caroline Fanning, co-founder of the Restoration
Farm that hosts one of Peterson's bee hives. "It didn't work out that way. I
had high incidences of _Varroa_. That's why we have Don coming in to take
care of the hives."
Because the infestation is so common, beekeepers have to focus on keeping
the _Varroa_ manageable, rather than preventing infestations, Peterson said.
A level of _Varroa_ mites greater than 3 for every 100 bees is unsustainable
to the colony, according to Mullen's report.
"By themselves, they may not be such a problem, but when you start adding in
all these other viruses, lack of forage, pesticides,"
Peterson said. "People like to look for the magic bullet that's going to
solve all these issues with bees. I think what we're seeing is a scenario of
'death by a thousand cuts'. "
Ball said that with all those variable threats to bee colonies, it's
difficult to focus the department's resources in combating pollinator
population decline. DEC officials added that there is not enough information
available to know which direction to take in drafting policy.
"I think we need a little more research," Ball said. "[_Varroa_] is a very
significant player, more than we previously understood, so let's dial that
in a little closer and see if there are additional management practices that
we can put in place."
[Byline: Christopher Cameron]
ProMED-mail from HealthMap Alerts
[The _Varroa_ mite can only reproduce in a honey bee colony. It attaches to
the body of the bee and weakens it by sucking fat bodies.
In this process, RNA viruses such as the deformed wing virus (DWV) spread to
bees. Mounting evidence indicates that bee colony collapses are caused by
interacting stress factors that affect the balance between pathogens and
It has been shown that otherwise silent infections with DWV become
uncontrollable and kill the bees when accompanied by infection with the mite
_Varroa destructor_. Other studies implicated pesticides interacting with
cold. It is likely that many factors, mostly anthropogenic stressors,
interacting in synergy disrupt the health of bees and make them less capable
of resisting infections, including _Varroa_ mites.
For a picture of _V. destructor_ go to
A HealthMap/ProMED-mail map can be accessed at:
Deformed wing virus, varroa mite, apis: manmade global spread, RFI
Varroosis, apis - Australia (04): (QL)
Varroosis, apis - Australia (03): 1st report, _V. jacobsoni_ Java/PNG
Varroosis, apis - Australia (02): 1st report, OIE, _V. destructor_ excluded
Varroosis, apis - Australia: 1st report, OIE
Varroa mite, bee - New Zealand
Varroa mite, bees - New Zealand (S. Island): alert
Bronze bee mite - New Zealand