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Red fowl mites and Northern fowl mites look roughly similar without inspection with a microscope. Adult mites have 8 legs and are approximately 1 mm long with a dark red to black appearance. Larvae have 6 legs and may be lighter in colour or pale as they do not contain the hosts blood.
Distribution and host range
Red Fowl Mites and Northern Fowl Mites are more prevalent in chicken coops, but may also become numerous outdoors. Both mite species are wide spread across New Zealand and are usually transported by wild birds.
Signs and symptoms
Signs and symptoms of red fowl mites include:
Life history and habits
Adult red fowl mites and northern fowl mites are about 1 mm long and dark red to black in appearance. There are four stages in the mite life cycle: egg, larva, nymph, and adult. The complete life cycle from egg to egg-laying female can be as little as five to seven days. This can result in rapid increases in mite populations, especially on layers and breeders kept for extended periods.
Female adult mites lay eggs directly on their host. The eggs hatch in one to two days, depending on the temperature and humidity. The larvae do not feed on the bird; however, larvae rapidly develop to the nymph stage in about eight hours. The nymphs do feed on blood from the birds and become adults within four to seven days.
Adult female mites complete the egg-laying process within two days after taking a blood meal from their host. The number of eggs laid per female is relatively low, usually two to five. However, the short life cycle means that mite populations can increase rapidly, with newly infested birds capable of supporting a mite population in excess of 20,000 per bird in 9 to 10 weeks under favourable conditions.
Red fowl mites can survive for as long as 8 months without feeding, northern fowl mites can only survive a few days without a host to feed on.
Red Fowl Mites remain hidden most of the time in protected areas around the cages and support materials. At night red fowl mites return to the birds to resume feeding. It is best to search for mites around cracks and under feed trays or water lines. Birds can also be inspected at night when the mites are feeding.
Northern Fowl Mites remain on the birds as they cannot go for extended periods without feeding. It is best to examine birds carefully to check for mites and eggs amongst the feathers.
A number of practices are recommended to prevent or minimise the establishment of fowl mites in chicken coops. These include:
The predatory mite, Stratiolaelaps spp. is the most commonly used biological control agent for fowl mites. Stratiolaelaps spp. is available from BioForce Ltd, who sells the product Poultry Defender™.
A range of insecticides are claimed to be effective against mites, although few have specific registration claims for use in chicken coops or on poultry.
Exolt is a very effective but resistance will develop if over used. Common Acaricides (pesticides such as spinosads and pyrethrins) have had resistance develop in many areas. Ivermectin is off label and should result in default egg and meat residues with-hold times (63 days meat and 10 days egg).
Care should be taken to consider the effect of insecticides on beneficial insects or mites that may be being used in integrated pest management programmes. Consult with BioForce Ltd before applying any insecticide when beneficial insects or mites are being used.