Red Poultry Mite

The Red Poultry Mite (Dermanyssus gallinae) is the most economically harmful parasite of laying hens in Europe. "A study by Guy et al. (2004) confirmed the widespread prevalence of D. gallinae in commercial laying hen housing systems in the U.K. with the finding that 87.5% of premises surveyed were infested and population levels were higher in free-range units compared with cage systems."


 * "This blood-feeding pest causes production losses due to irritation and anaemia and may even cause death of its host. The mites stay on the host only to feed, and then move into neighbouring cracks and crevices to lay eggs (Hearle, 1938). Under favourable conditions, the life cycle of the parasite can be completed within 1 week, and a high reproduction rate may occur as the feeding-oviposition cycle repeats about every third day (Kirkwood, 1963; Desch, 1984), and large populations can be rapidly established. The mites occur in both battery cages and floor systems. However, the problem is more common and widespread in the latter (Höglund et al., 1995). This is probably attributed to the presence of numerous suitable hiding places for the mites in most floor systems."

Life Cycle

 * "The red mite resembles the northern fowl mite (Ornithonyssus sylviarum) in both size and appearance, but its life cycle differs in that the red mite spends the most of its life away from the birds. Red mites only parasitize birds in darkness in order to feed. In farms with battery-cage systems mites are hidden under the conveyor belts of eggs and cage supports. In farms with slatted flooring systems, mites are hidden under the rods, in nest boxes, beneath troughs and in small cracks and crevices in the poultry house walls.


 * "Nymphs and females suck blood while males do so very occasionally and larvae do not feed. Dermanyssus stays on the birds for only 0.5-1.5 h to feed.


 * "Adults mate soon after molting. After fertilization the females begin depositing eggs within about 12 h after feeding. They will feed and deposit eggs several times. Each female is able to lay about 30 eggs in its lifetime.


 * "The egg is small... oval, smooth and pearly white. Under warm conditions (28-30C) a larva emerges in 2-3 days. The young larva is white, has 6 legs, and moves about slowly and after 1 day molts to the protonymph stage without feeding. The protonymph has 8 legs; it feeds and molts to a deutonymph which feeds again before becoming an adult... In optimal conditions the life cycle (egg-to-egg) can be completed within 7 days.


 * "Red mites may live up to 8 months away from poultry. They resist desiccation but cannot tolerate high humidity."


 * "Nymphs are the most starvation-resistant stage of D. gallinae (Nordenfors et al., 1999), where they can in fact survive without taking a blood meal for 28 weeks (Harrison, 1960; Kirkwood, 1963)."

Impact of Temperature
A study found that "The most favorable temperatures for the juvenile development seem to lie between 25 and 37C where the developmental rates are highest and the mortalities are relatively low and constant. The mites can develop and reproduce in a wide range of temperatures and it seems that higher temperatures are less restrictive for their development than lower ones; this is reflected by serious outbreaks of D. gallinae during the warm summer months." (25-37C = 77-98.6F) Additionally, adult females laid the most eggs at 28.6C, although they continued to lay eggs at all temperatures, even as low as 5C (41F). At 40C (104F), the eggs were unable to develop. Another study found:


 * "The development, viability, and life cycle parameters of Dermanyssus gallinae at five different temperatures (15, 20, 25, 30 and 35 C), and at relative humidity 70–85% were evaluated. Life cycle duration was 690.75 h (28 days) at 15 C [59F], 263.12 h (11 days) at 20 C [68F], 164.63 h (7 days) at 25 C [77F], 140.69 h (6 days) at 30 C [86F] and 172.04 h (7 days) at 35 C [95F]. The optimal development temperature for D. gallinae was 30 C, with the greatest survival in all stages and the shortest development time. High mortality at 35 C indicated that this temperature had adverse effects on development of D. gallinae, and that in field conditions D. gallinae populations may decrease or even disappear due to the negative impact of high temperature on development."

Behavior
In a study, mites were attracted to aged feathers (feathers found in litter that were not contaminated with fecal matter), CO2 approximating the concentration exhaled by chickens, and other mites of the same species. "Poultry red mites are extremely sensitive to temperature changes and it is very likely that this heat sensitivity plays an important role in the process of detecting and possibly locating new hosts."

Red poultry mites will bite humans, cats, and dogs as well as chickens.

Controlling Red Mites

 * "Current D. gallinae control is primarily based on sanitising empty poultry houses between flocks and the use of acaricides; mainly organophosphates, carbamates and pyrethoids. However, field studies have shown that these methods may have a limited effect as mite popu- lations often rebound after only temporary suppression (Nordenfors and Höglund, 2000). D. gallinae is difficult to eradicate from infested farms due to its short lifecycle, high reproduction rate and increasing resistance to commonly used acaricides that are becoming less efficient in D. gallinae control as a result (Beugnet et al., 1997; Nordenfors et al., 2001; Zeman, 1987). Alternative strategies are being developed to efficiently control this pest, though many of these remain at the experimental stage (Harrington et al., 2009)."

Traps
A 2002 study found that using corrugated cardboard traps (100mm × 70mm × 3mm) treated with pesticide was effective in controlling mite populations. The traps were placed out of reach of the birds around the coop and were replaced every second day. While this can be done with synthetic pesticides, it is also possible to create traps using organic substances that kill mites. One study (see below) used cardboard traps with a 20% neem solution, allowing the traps to dry for 24 hours after treatment before placing them in the chicken coop.

Inert Dusts

 * "The treatment against poultry red mite using inert dust is a relatively new event. As the air humidity levels in poultry production facilities are often high this may hamper the efficacy of the inert dusts. Inert dusts mainly act as dessicants by absorbing the lipids of the cuticle surface (Ebeling 1971) leading to death of the arthropod as a result of water loss, so high humidity in general is less conducive to the action of inert dusts (Subramanyam and Roesli 2000; Nielsen 1998)."

A 2009 study found that synthetic amorphous silica was the most effective at killing mites, followed by mixtures of synthetic amorphous silica and diatomaceous earth, followed by pure diatomaceous earth. Kaolin and talc were also tested and they produced the poorest results. Another study tested three silicas (one synthetic amorphous silica, one diatomaceous earth (DE) and one DE with 2% pyrethrum extract) and found the opposite results - that DE was effective in killing mites but synthetic amorphous silica was not. However, both products did stop mite reproduction.

A 2011 study of ethnobotany also found that farmers dusted the chickens with diatomaceous earth to control mites and used wood ash in addition to diatomaceous earth, placing both where the birds would dust bathe. After cleaning the coop, farmers would put a layer of ash on the floor.

Oils
A 2009 study compared the effects of mineral oil, rapeseed oil, orange oil, and soap. The best results were achieved with mineral oil, followed by orange oil (at a concentration of 50g/l), followed by rapeseed oil. Mites treated with 100% soap did not reproduce but the soap did not kill many mites, particularly compared with other substances tested.

Plant-Based Products
Pyrethrum: A 2009 study found that treatment with 0.2% pyrethrum killed mites effectively and even had some effect at a 0.02% dose.

Neem: A 2010 study using a specific neem product caled Mite-Stop had excellent results:
 * "The in vitro and in vivo experiments show that the neem seed extract diluted at 1:33 with tap water kills all stages of the blood sucking mite D. gallinae. Lower concentrations or in cases when mites do not come into direct contact with the acaricidal plant compound some mites may survive. Such cases make it necessary, that treatment is repeated at least twice at an interval of 5-7 days."

Garlic:A 2009 study found that 100% fresh-pressed garlic juice killed mites even more effectively than pyrethrum, and even a 10 percent solution had a significant impact. However, tansy (Tanacetum vulgare), garlic juice, Mohave yucca (Yucca schidigera) leaves, Soapbark tree bark (Quillaja saponaria), and ethanol solutions made with the leaves of Dryopteris filix-mas and Thuja occidentalis (arborvitae) were not effective.

Tobacco: A study in ethnobotany found that farmers used chopped, dried tobacco stems to control mites. They placed this in the nest boxes of broody hens.

Cedar: "Western red-cedar shavings were used in poultry litter, particularly in nest boxes of broody hens, to protect poultry against red bird mites. Thuja occidentalis was tested and found to have some effectiveness against the poultry red mite Dermanyssus gallinae."

Essential Oils:
 * "Work from Korea tested a range of different plant essential oils for their acaricidal effect on D. gallinae (Kim et al., 2004). Of the 56 oils tested those from bay, cade, cinnamon, clove bud, coriander, horseradish, lime dis 5F, mustard, pennyroyal, pimento berry, spearmint and thyme all gave 100% mite mortality in contact toxicity tests at a concentration of 0.07 mg of oil per cm2. Neem oil has also been tested against D. gallinae, with a 92% reduction in mite numbers in poultry houses fitted with traps containing 20% neem oil in water compared to those containing water alone (Lundh et al., 2005). More recently, George et al. (in press) investigated the toxicity of 50 plant essential oils to D. gallinae and found of these, 20 essential oils provided greater than 80% mite mortality over a 24 h period in contact toxicity tests at a level of 0.21 mg/cm2, with one in five oils giving 100% mortality at this dose. This work also showed that most essential oils were stable in their toxic effect to D. gallinae under varying temperature, humidity and dust levels."

A study published in 2009 found that fumes of essential oils of thyme, pennyroyal, and manuka were all toxic to red mites:


 * "That the essential oils used in this study appear to act against D. gallinae primarily by fumigant toxicity could be seen as an advantageous attribute of these products. The behavioural ecology of D. gallinae is such that it seeks refuge in the cracks and crevices of the poultry house when not feeding (with mites only feeding for short periods every few days during the hours of darkness) (Bruneau et al., 2001). This may make it difficult to eradicate D. gallinae by means of a contact-dependent acaricide, especially if such a product relies on rapid knock-down to be most effective. If essential oils are toxic to D. gallinae in their vapour phase, however, acaricides based on these products could be expected to penetrate poultry house sub-structures, killing even those mites present in refugia during application."

In experiments, essential oils from both thyme (Thymus vulgaris L.) and cade (Juniperus oxycedrus L.) were effective over 24 hours, but cade was not so effective over shorter periods (thyme was).

Another study examined the effects of essential oils of manuka, cade, pennyroyal, thyme, garlic, clove bud and cinnamon bark on various life stages of red mites. All were effective against adult mites. "Juvenile mortality was significantly higher (P < 0.05) than adult mortality following exposure to cade, clove bud and garlic essential oils." Pennyroyal, garlic or cinnamon bark oils were all toxic to mite eggs, whereas manuka, cade, thyme or clove bud essential oils were not.


 * "At a level of 0.21 mg/cm2, the essential oil from Eucalyptus citriodora achieved 85% mortality in D. gallinae over a 24 h exposure period in contact toxicity tests. A further two essential oils from different eucalyptus species, namely E. globulus and E. radiata, provided significantly (P < 0.05) lower mite mortality (11 and 19%, respectively)."

Other studies found that gum resin from Commiphora holtziana (Burseraceae), known as gum haggar, and essential oils from catnip could serve as repellants to red mites.

Predatory Mites
A 2009 study seeking predators to red poultry mites identified Hypoaspis aculeifer and Androlaelaps casalis as possibilities.

A different group of scientists tested four species of predatory mites, (Hypoaspis miles, Hypoaspis aculeifer, Amblyseius degenerans, and Phytoseiulus persimilis). Two species had no predatory effect at all, but both Hypoaspis miles and Hypoaspis aculeifer did prey on the red poultry mites. "H. miles was shown to be the most effective predator per se, accounting for nearly 40% of D. gallinae mortality over 48 h, though results were statistically similar for both Hypoaspis species." For H. miles, predation increased as temperatures increased.


 * "Though the results presented herein for H. miles are encouraging, little can be concluded on the commercial feasibility of biological control for D. gallinae from these data alone. Additional studies encompassing all predator/prey life-stages and across multiple generations will be critical to ascertain if H. miles can be released at an economically acceptable rate to provide prolonged and effective management of D. gallinae populations. Encouragingly, observations already suggest that H. miles can complete its entire life-cycle on a diet of D. gallinae (Tuovinen, 2008), with H. aculeifer recorded as consuming both eggs and all mobile stages of this pest (Lesna et al., 2009)."

Another study tested two species of predatory mites (Androlaelaps casalis and Hypoaspis miles) in battery cages housing laying hens. Both preyed on the poultry mites, but A. casalis was more successful than H. miles in all tests. A test conducted at 26C (78.8F) and one in which temperatures were kept at 33C (91.4F) during the day but dropped to 25C (77F) at night were more successful than one with a constant temperature of 33C.

H. miles (also known as Stratiolaelaps scimitus) are already used in organic agriculture to control thrips and fungus gnats, and they are commercially available.

Fungi
A 2011 study in Iran tested the ability of the fungi Metarhizium anisopliae to control red mites. All three strains tested were effective (although only at the higher concentrations tested).

Spinosad
Spinosad, "a natural product derived from the fermentation of the micro-organism Saccharopolyspora spinosa," was found effective in controlling mites:


 * "In vitro testing confirmed that, when applied to a galvanised metal plate to the point of run-off, spinosad was toxic to adult female D. gallinae and suggested that at an application rate of 3.88 g/L a significant residual toxicity of spinosad could be achieved for up to 21 days. A subsequent in vivo experiment in a conventional cage housing system for laying hens demonstrated the acaricidal activity and residual toxicity to D. gallinae of a single application of spinosad when applied at either 1.94 or 3.88 g/L. Residual toxicity of spinosad at both of these application rates was maintained throughout the course of the 28 day post-spray study period, with a peak in product efficacy seen 14 days after spraying. The results suggest that the greater the D. gallinae population the greater will be the toxic effect of spinosad."

Related SourceWatch articles

 * Northern Fowl Mite

External articles

 * K. Huber, L. Zenner, D.J. Bicout, "Modelling population dynamics and response to management options in the poultry red mite Dermanyssus gallinae (Acari: Dermanyssidae)," Veterinary Parasitology 176 (2011) 65–73.
 * M. Tavassoli, M. Allymehr, S.H. Pourseyed, A. Ownag, I. Bernousi, K. Mardani, M. Ghorbanzadegan, S. Shokrpoor, "Field bioassay of Metarhizium anisopliae strains to control the poultry red mite Dermanyssus gallinae," Veterinary Parasitology 178 (2011) 374–378.
 * Michael A. Birkett, Ahmed Hassanali, Solveig Hoglund, Jan Pettersson, John A. Pickett, "Repellent activity of catmint, Nepeta cataria, and iridoid nepetalactone isomers against Afro-tropical mosquitoes, ixodid ticks and red poultry mites," Phytochemistry 72 (2011) 109–114.
 * D.R. George, R.S. Shiel, W.G.C. Appleby, A. Knox, J.H. Guy, "In vitro and in vivo acaricidal activity and residual toxicity of spinosad to the poultry red mite, Dermanyssus gallinae," Veterinary Parasitology 173 (2010) 307–316.
 * D.R. George, O.A.E. Sparagano, G. Port, E. Okello, R.S. Shiel, J.H. Guy, "Environmental interactions with the toxicity of plant essential oils to the poultry red mite Dermanyssus gallinae," Medical and Veterinary Entomology (2010) 24, 1–8.
 * C. J. M. Koenraadt and M. Dicke, "The role of volatiles in aggregation and host-seeking of the haematophagous poultry red mite Dermanyssus gallinae (Acari: Dermanyssidae)," Exp Appl Acarol (2010) 50:191–199 DOI 10.1007/s10493-009-9305-8.
 * D.R. George, T.J. Smith, R.S. Shiel, O.A.E. Sparagano, J.H. Guy, "Mode of action and variability in efficacy of plant essential oils showing toxicity against the poultry red mite, Dermanyssus gallinae," Veterinary Parasitology 161 (2009) 276–282.
 * Lesna, I., Wolfs, P., Faraii, F., Roy, L., Komdeur, J., Sabelis, M.W., 2009. "Candidate predators for biological control of the poultry red mite Dermanyssus gallinae." Exp. Appl. Acarol. 48, 63–80.
 * Mul, M., van Niekerk, T., Chirico, J. et al. (2009) Control methods for Dermanyssus gallinae in systems for laying hens: results of an international seminar. World’s Poultry Science Journal, 65, 589–599.
 * Jenny Lundh, Daniel Wiktelius and, Jan Chirico, "Azadirachtin-impregnated traps for the control of Dermanyssus gallinae," Veterinary Parasitology 130 (2005) 337–342.
 * Nordenfors, H., Chirico, J., 2001. Evaluation of a sampling trap for Dermanyssus gallinae (Acari: Dermanyssidae). J. Econ. Entomol. 94, 1617–1621.
 * Claude Chauve, "The poultry red mite Dermanyssus gallinae (De Geer, 1778): current situation and future prospects for control," Veterinary Parasitology 79 (1998) 239-245.