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Leatherjackets
Leatherjackets are the larval stage of the
crane fly or daddy-long-legs.
Leatherjacket larvae are about 2.5cm (1"
long), greyish black in colour, legless and with no distinct
head.
In summer leatherjackets pupate. In August
they start to lay eggs re-infesting lawns. Within two weeks eggs
hatch. The young start to feed, continuing throughout winter, ready
to gorge on grass roots in spring. Grass growth slows and yellow
patches appear. Grass is easily pulled up, with little or no root
growth.
In August gardeners may see clouds of
daddy-long-legs emerging from lawns in the early morning and this,
as well as the listed damage, are sure signs of leatherjacket
infestation.
Starlings peck at the grass in an attempt to
eat the grubs.
Wildlife, such as foxes and badgers, can also
create a lot of damage as they dig up your lawn in search of grubs
for food.
There is no chemical control for
leatherjackets.
Leatherjacket Killer
Apply when the young leatherjackets are active
in the soil, this is typically late August through to the end of
October.
When you start to see the adult
daddy-long-legs in your garden (towards the end of August) you will
know that in a few days they will be laying eggs. These will hatch
quickly, therefore, aim to apply about a week to two weeks after
you see the adults.
Apply to moist lawns when the soil temperature
is above 12ºC (54ºF) and water them in well. The nematode needs to
be washed well in so that they reach the roots where the
leatherjackets will be. Make sure the lawn does not dry out after
applying nematodes.
Immediately after applying the nematodes,
water the grass well so the nematodes are washed into the soil to
reach the roots where the leatherjackets will be. Make sure the
lawn does not dry out after applying nematodes. Keep the lawn well
watered for at least two weeks.
The nematodes (Steinernema feltiae),
seek out the leatherjackets and attack the pest by entering natural
body openings. Once inside, they release bacteria that stops the
pest from feeding, quickly killing the pest. They do not stop
there. The nematodes reproduce inside the dead pest and release a
new generation of hungry infective nematodes, which disperse and
search for further prey.
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