Page 10 - aUgUst 4, 2016 - martensville messenger
GARDENING
Pear slug: not a slug, But Just annoying
If you own a cotoneaster
hedge, you know what
pear slugs are. They are
relatively small (5 to 12
mm long) and initially
slimy, green-black slug-like
creatures that, in bad years,
can cover your hedge,
gradually
skeletonizing
the leaves. I say ‘slug-like’
since they are actually the
immature (larval) form
of Caliroa cerasi, a small
sawfly, related to ants,
bees and wasps rather
than to common garden
slugs, snails and their ilk.
They attack other plants
in addition to cotoneaster:
pear (of course), plum,
mountain ash, saskatoon
berry, cherry, pin cherry,
hawthorn and chokecherry.
For effective control, I
always say, know your
enemy. This particular
enemy overwinters in a
cocoon 5 – 8 cm below the
soil surface near the base of
host plants. Adults emerge
in June and early July. After
a brief love affair, females
insert their eggs under the
leaf surface. Larvae hatch
after one to two weeks and
then begin stripping the leaf
surface between the veins.
During their early immature
stages (instars), larvae
appear slimy, dark greygreen, lack distinct legs and
have an obvious larger head
then the rest of their body.
In the final larval stage, they
resemble small, yelloworange caterpillars now
with distinct legs (which
true slugs will never have).
Larvae complete their
Submitted by Erl Svendsen
developmental phase after
two to three weeks and
then drop to the ground
where they pupate in
below-ground
earthen
cells. In favourable years
(that is for pear slugs), a
second adult generation
may emerge in August
to start the cycle again.
This second generation
is naturally larger than
the first and hence more
damaging.
Initially,
damage
may appear as leaf
discolouration, mottling,
or small yellow spots. As
feeding continues, affected
areas expand, forming
distinct white or reddishbrown patches. Because
of
their
contrasting
colour, the larvae are quite
noticeable.
Management should be
focused on the relatively
slow-moving larvae since
trying to control the
short-lived, faster adults
(slightly larger than a
housefly) is not practical.
Start looking for insect
damage in late June/early
July. Continue monitoring
for the rest of the summer.
Control is most effective
when the infestation is
small and in the early
stages.
With small infestations,
handpick affected leaves
(complete with pear slugs)
and drop them into soapy
water. In the fall, remove
all leaves and lightly rake
the soil around plants to
expose cocoons (try not
to cause too much root
damage). With heavier
infestations and when
leaves are out of easy reach
on taller shrubs and trees,
products containing carbaryl
(e.g. Sevin) and insecticidal
soap are registered for
pear slug control. Before
spraying, make sure you
still have something to
control:
mature
larva
may have already exited
the scene to overwinter
underground leaving behind
just the damaged leaves.
Always read pesticide
labels carefully for correct
application, timing and
safety
precautions.
If
spraying on fruit bearing
trees and shrubs, pay
particular attention to preharvest interval (minimum
number of days to wait
between spraying and
harvest).
This
column
is
provided
courtesy
of
the
Saskatchewan
Perennial
Society
( w w w. s a s k p e r e n n i a l .
ca;
hortscene@yahoo.
com; www.facebook.com/
saskperennial).
Check
out our Bulletin Board or
Calendar for upcoming
garden
information
sessions,
workshops,
tours and other events:
August 6, Country Garden
Tour
(306-242-2320;
saskatoonhortsociety@
sasktel.net;
www.
saskatoonhortsociety.ca);
GardenLine is here for the
season to help solve your
gardening glitches. FREE.
Phone (306) 966-5865 or
email [email protected].
JP Massage Therapy
Phone: 306 382-0893
Firefly Counselling Services located inside our clinic
www.fireflycounsellingservices.com - 306-715- 4116
5A - 7 Centennial Drive North - Martensville
Beware of Wild Parsnip
With
summer
here,
many area residents take
to the open road and
travel to one of the many
lakes,
campgrounds,
and communities that
Saskatchewan has to offer.
There are many things to
be aware of when heading
for the great outdoors,
including the wild parsnip
that can now be found
within the province. Many
of us are familiar with
parsnips, however the wild
parsnip is not a vegetable,
but instead a weed that can
cause severe health issues
for those that encounter it.
The wild parsnip, also
known as poison parsnip,
produces a chemical within
its sap that can cause skin’s
sensitivity to ultraviolet
light to increase. For
those that come into slight
contact with the weed, it
can cause a reaction similar
to poison ivy, however,
Shanine Sealey, Martensville Messenger
for more severe contact,
such as trying to pull the
weed, the reaction is far
more severe. If skin comes
into contact with the sap
from broken stems, leaves
or flowers, and is then
exposed to UV light, it
creates a reaction that will
produce second degree
burns, blisters or rashes,
with effects that can last
on the skin for years
following the encounter.
If sap gets into the eyes,
it would feel like pepper
spray and can cause
temporary, or permanent
blindness. Once exposed,
skin can have an extreme
reaction to UV light for up
to three years following, in
which case, every time the
skin experiences UV light,
a reaction would occur.
Wild parsnips have been
found throughout the
province, with one of the
worst locations being
found within the area
between Saskatoon, and
Prince Albert, in the Duck
Lake vicinity.
The plant can also cause
dangers to livestock and
pets, as animals skin reacts
the same and if they ingest
the plant, it can reduce
their ability to gain weight,
as well as reduce their
fertility.
The weed also causes
concerns
within
the
surrounding environment,
as it is extremely aggressive
and can take over areas and
destroy other plants within
the area, causing animals
to avoid the local area.
If you see a wild parsnip,
do not attempt to remove
the plant, instead call your
local weed inspector, or the
Agriculture
Knowledge
Centre for details on how
to control the weed.
LEFT: Wild
Parsnip has
been spotted
growing
within the
area between
Saskatoon
and Prince
Albert, around
Duck Lake.
(PHOTO:
H. Zell,
commons.
wikimedia.org)