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Description
Order: Acarina Mesostigmata/Gamasina

Characteristics:
Usually less than 2 mm long. There is little
evidence of segmentation. The body consists of
the sac-like idiosoma and the gnathosoma, which
carries the mouthparts and sensory organs. The
mouthparts include a pair of 3-segmented
chelicerae, which may be pincer-like or piercing.
The idiosoma is rounded or oval and the dorsal
surface sclerotized with shield-like plates. Adults
have eight legs, which are usually well developed,
the front pair being employed as sensory organs
rather than for walking. There is a single pair of
spiracles opening between the second and third or
third and fourth pair of legs. Metamorphosis is
incomplete with egg, larval and nymphal stages.

Species characteristics:

Poultry Red Mite (Chicken Mite)
(Dermanyssus gallinae)
Adults, 0.7 –1.0 mm long; idiosoma oval, colourless
to bright red or grey-black (if containing
partially digested blood); chelicerae of females
well developed, narrow towards the tip and
approximately half as long as the idiosoma; dorsal
surface with weak sclerotisation and pairs of
setae.

Northern (European) Fowl Mite
(Ornithonyssus sylviarum)
Sometimes confused with the Red Poultry Mite
although it lives on the host and is active during
the day. Chelicerae do not narrow at the tip and
bear shear-like chelae with no teeth or setae;
sternal plate with two pairs of setae


Areas where found
A cosmopolitan species widely distributed
throughout Europe. It is found naturally in wild
bird nests, the small size of the mites making
them ideally suited to a close association with
birds. They feed on blood and are particularly
associated with the nests of pigeons, starlings,
sparrows, swallows and house martins. When the
birds fledge and leave their nests the mites may
disperse and infest nearby buildings including
poultry units. Adult mites are resistant to dessication
and starvation and can survive without food
for several months. Extreme temperatures e.g.
>45° C and -20° C are lethal and survival is best
at higher relative humidities e.g. 70%.
Red poultry mites are important pests in poultry
units and appear in all types of production
systems. Conditions in poultry houses are ideal
for the mites and large populations can rapidly
develop. The mites are nocturnal and spend the
day resting in cracks and crevices where they are
safe from predation by the birds. At night time
they quickly move onto the birds and will feed for
up to two hours. Freshly fed mites are bright red
in colour but, as the blood is digested, they
gradually turn darker and eventually become
colourless.
Mites can be introduced into poultry units from
infestations associated with wild birds, with newly
introduced poultry, on equipment, transport or
clothing.


Importance as a pest
When the mites infest buildings they will attack
people causing painful and irritating bites.
Large infestations in poultry houses may lead to a
number of problems including:
Disturbance and stressing of the birds, which may
be reluctant to use infested nests.
Increased feather pecking.
Anaemia, leading in severe cases to death.

Transmission of diseases.
Red poultry mites are implicated in the
transmission of Salmonella spp., Erysipelothrix
rhusiopathiae (the causative agent of erysipelas),
Newcastle virus etc.

Reduced productivity:
Reduced weight gain.
Reduced egg production.
Reduced quality of eggs:
Smaller eggs.
Inferior shell quality.
Inferior yolk colour.
Contamination with mites and their faeces.


Life-Cycle
Female mites lay as many as 40 eggs in batches
up to seven at a time, 12–24 hours after taking a
blood meal. The eggs are oval, cream-coloured
and approximately 0.4 mm long. They are laid in
nests, cracks and crevices around roost sites and
hatch in 1–3 days to give 6-legged larvae. The
larvae do not feed and remain inactive until they
moult within two days to give 8-legged nymphs.
Like the adults, nymphs take blood meals, usually
during the night, and spend the day sheltering in
cracks and crevices in and around the nests.
There are typically two nymphal stages before
they moult to become adults. Under favourable
conditions the full life-cycle takes about a week.


Control
Assessment of infestations
Populations of Red poultry mites can establish
themselves very quickly and, as infestations
become deep-seated, they are difficult to control.
Regular monitoring is important to ensure
infestations are dealt with at the earliest
opportunity. Mites may be collected from birds or
resting sites, but the fact that they are not active
during the day and hide in cracks and crevices
means it may be difficult to measure populations.
They can be expelled from harbourages e.g.
equipment by tapping them onto sheets of paper.

a) Hygiene/management
Infestations associated with wild bird nests can be
controlled by removing and destroying the nests
with due regard to any statutory protection which
exists for the bird species involved.

In poultry houses, efforts should be made to limit
the harbourages available for the mites. This can
be achieved by limiting the use of wood, employing
impervious materials which are easy to clean,
equipment design and sealing potential refuges.
Care should be taken not to introduce infestations
via newly introduced poultry, on equipment,
transport or clothing. Buildings should be proofed
to prevent the ingress of wild birds, which may be
infested.
Thorough cleaning of the empty poultry house,
including the outside, by power washing, steam
cleaning etc. will control the mites and should
precede the application of acaricides. Equipment
should be dismantled as necessary and be
thoroughly cleaned.

b) Acaricidal control
Where infestations are associated with wild bird
nests, the infested areas should be treated with a
suitable acaricide.

Infested areas of poultry houses should be
treated as soon as they are identified, paying
particular attention to mite harbourages.
Thorough treatments with acaricides should also
be made when houses have been cleared and
cleaned.


Advice
Bayer has an extensive range of products specifically formulated for the control of flying and crawling insect pests.

Further information on all Bayer Environmental Science professional pest control products is available from:

Bayer Environmental Science
230 Cambridge Science Park, Milton Road
Cambridge, CB4 0WB.
Tel: 01223 226680 Fax: 01223 226635

The greatest care has been taken to ensure the accuracy of the information contained in this guide. In no circumstance, however, will Bayer Environmental Science be liable in respect of any error or omission.

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