The Rural Voice, 2003-06, Page 494
Gardening
Thoughts on larvacide and West Nile Virus
Rhea
Hamilton -
Seeger and
her husband
live near
Auburn. She
is a skilled
cook and
gardener.
By Rhea Hamilton -Seeger
In May a natural mosquito killer
was offered for sale to the public as
another tool to use against the spread
of West Nile virus. There has been
a lot of pressure from both the public
and the media for the provincial
government to do something about the
spread of West Nile virus. Many health
units and boards of health have chosen
to look at education first.
By now you will have heard the
message at least twice: drain the rain,
cover up, and use an insect repellent.
There have been differing statistics on
how many people were actually
infected last year and how many died
from this disease. The provincial
government, in this election year, has
decided to promote the use of
larvacide and even go so far as to
demand it be applied in municipalities
were there are confirmed cases of birds
dead from West Nile virus.
So what has this to do with
gardeners? Gardeners and farmers,
people who work closely with the land,
may have a more intimate appreciation
for nature and how we merge or fit into
the big picture. When you consider the
number of people who die each year
from cigarette smoking or the effects
of second hand smoke, West Nile
virus is small potatoes.
Gardeners are a cautious lot when it
comes to introducing chemicals into
their gardens and if you're not, you
should be. I literally felt sick to my
stomach when the provincial govern-
ment announced plans to demand the
use of larvacide in municipalities. My
concern was with our rural areas and
our major wetlands. History has shown
us you cannot alter the food chain
without repercussions. We knock off
one species and find out later that three
others die off for want of the one we
killed. Our family lives on the southern
edge of one of Ontario's Class One
Wetlands, the Saratoga Swamp. I want
to share with you what 1 have found
out about the larvacide.
First of all money is always the
bottom line. The larvacide product that
is being promoted is fairly expensive
so we know that if there is any
distribution it will be restricted first to
populated areas by licensed operators.
The focus will be on standing water in
catch basins in the urban areas. Spray-
ing standing water in rural areas in a
bit silly when you consider how many
mosquitoes live in moist areas in the
bush, long grass. and in nooks and
crannies all over.
This larvacide is a natural bacteria
called Bacillus thuringiensis israelensis,
or Bti for short. It is the active agent
in Aquabac, the brand name of the first
biological larvacide approved by
Health Canada's Pesticide Manage-
ment Regulatory Agency (PMRA) for
use around the house and garden.
Discovered in a puddle in Israel's
Negev desert in 1976, this bacteria can
kill all eight known types of
mosquitoes that carry West Nile during
a narrow window of several days in
their life cycle but does no harm to
mosquito predators like dragonflies,
other insects, fish, or frogs.
Because it works within minutes of
entering the larvae, the larvae have
no time to mutate and develop a
resistance to Bti. During the 20 years it
has been in use there are no published
accounts of Bti resistance, unlike most
synthetic insecticides. Both the
Province and your local Board of
Health will look at the bottom line.
Chemical insecticides are cheaper and
last longer as opposed to Bti which
you have to reapply if you get repeated
rainfalls resulting in higher labour
costs. But the fact that Bti goes
completely dormant within several
days means there is no environmental
contamination. We have to stress to
our officials that the environment is
worth the cost.
So back to our gardens and our
communities. Education is still the first
line of attack. Mosquitoes will breed in
any standing water, so be critical
around your yard. Pick up the kids'
toys, don't leave your old saucers and
pots standing outside. Drain them and
put them away. That standing basket-
ball hoop you bought for the kids may
collect water at the base.
Mosquitoes need very little water to
lay larva in. If you have a fountain in
your pond this should deter
mosquitoes. If you have fish that is
even better. The still ponds or barrel
ponds that have become popular on
decks and patios will either have to
have a fish popped in or a mini pump
inserted to keep the water moving.
Yes I know wearing long sleeves at
dusk is a pain on a deliciously warm
summer evening, but think about this:
a large number of people who
contracted West Nile virus were
gardeners and people out enjoying the
outdoors. If you hate to cover up then
look to insect repellent with the
required active ingredient of DEET. If
you have any concerns or need more
information, phone your local health
department. There are fact sheets that
you can read and then post on your
fridge as a gentle reminder. If you are
involved with a larger issue like
cleaning up standing water around a
massive condominium block and want
to do something in a larger scale you
should contact the Ontario Ministry of
Environment — Regional Pesticide
Specialists. For The Rural Voice
readers that would be Southwestern
Region and the number is 1-800-265-
7672.
But my final word does not lie with
the mosquitoes and their demise but
with the flowers of spring. The cool
weather we have had has been perfect
for spring flowering bulbs. The
daffodils, narcissus, tulips, and
fritillaria have all lasted longer and put
on a wonderful show.
Bulbs don't need much in the way
of a boost. Fast acting fertilizers
should be avoided, especially those
high in nitrogen. Bonemeal fits the bill
if you want to give your bulbs a little
TLC. Work a little into the ground
beneath the bulbs when planting new
ones and then mark the area with a
circle of bonemeal. For the old bulb
patches lightly add bonemeal to the
surface, about one tablespoon for a
large bulb and a half cup for a dozen.
Smaller bulbs need less. Work it into
the soil a bit without damaging any
shoots. You can use wood ashes but
apply them early in the spring before
the shoots come up. Happy
gardening.0
JUNE 2003 45