Effectively tackling red mite in layers requires a stringent three-pronged approach at turnaround.
Every poultry producer knows that red mite can severely affect a flock’s health.
The stress levels imposed on layers by the pest may not severely hit egg production, but will reduce feed conversion. More generally, birds will become depressed and unthrifty.
Red mite impact on flocks
A lot of producers do not realise that red mite can be responsible for a host of production issues such as a sudden egg drop or an increase in mortality and yet it is often overlooked as the primary cause.
Red mite causes stress in birds so birds become very noisy and restless, there can be a production drop of up to 25% and then egg downgrades by blood spots, smears on the eggs.
Birds can become depressed, which causes reduced preening activity, dust bathing and loss of feather cover.
The knock-on effect is an increase in feed consumption as the birds feed intakes increase just to sustain body warmth.
Red mite can transmit salmonella, mycoplasma, pasteurella, erysipelas and E coli – those are the most common diseases, but they can also carry coccidiosis, too.
But aside from disease, the consequences of the infestation can be even greater because of the issues they cause to a flock through stress.
Skin irritation, depression, potential dermatitis and cannibalism are all symptoms of birds infected with red mite – ultimately anaemia and death can be the end result.
Why red mites infestations are difficult to control
It is important to fully understand how red mite reproduce in order to apply control measures.
The first, and possibly most important, point is that red mite can survive for a long time without feeding from their host – even when birds have left the shed the level of infestation will continue.
Alison Colville-Hyde, field services manager with St David’s Poultry Team in Devon says red mites have adapted well to infesting wherever poultry is present and has proven impossible to fully eradicate.
“This is a very resilient poultry ectoparasite and that’s what makes it so difficult to get rid of. Red mite can survive for several months without feeding and can continue to exist even though there are no poultry present to provide a food source.
“That’s why a totally effective cleanout of any buildings between batches is absolutely essential,” she says.
But no matter how effective, reinfection is highly likely – either by missing a small colony of red mite or on the body of the pullets that make up the next flock.
They can even migrate on wild birds into poultry sheds.
Multi-age sites are often tricky to manage, but the mite can crawl from shed to shed – and carry disease with them.
So a determined and effective control protocol needs to be put in place if there is any chance to prevent infestation.
How temperature affects infestation
“The speed of the lifecycle will vary – up or down – depending on the environmental temperature, so it’s not simply a case of eggs being laid and adults hatching in due course,” says Allison Colville-Hyde.
Adult red mite lay eggs which turn into larvae; this is followed by two nymph stages before the mites are actually able to reproduce and lay eggs themselves.
Furthermore, red mite have to have a “blood meal” before they are capable of breeding and laying eggs themselves.
In the adult stage the female mite must have a blood meal every time she is going to lay a clutch of eggs.
At 5C (environmental temperature) a female is capable of laying 150 eggs per clutch; if that temperature rises to 25 degrees the clutch size can increase to around 300 eggs and the life cycle length will speed up.
So in the summer months, when the temperature rises by a few degrees in the poultry shed, it will be sufficient to trigger a higher output from the female mites creating a population explosion in a short timeframe.
Red mite facts
- One bird can carry 500,000 mites while they feed, which usually takes about two hours.
- Red mite can suck up to 5% of a hen’s blood in one night.
- They communicate with members of the colony using pheromones that signal when to return to the crevices in the shed.
Once the date is known for flock depletion, it’s important to get back into the shed that night, or very early the next day, to clean with a strong detergent solution and to spray down the entire house with an acaricide.
When the birds have gone the temperature in the house drops and the mites can detect this.
They don’t have eyes but have feelers; they are highly sensitive and, realising their food source has gone they will immediately move away to the deep crevices and infrastructure of the building, and that’s where they will stay.
It is therefore critical to apply detergent to the building as soon as possible to try and have an impact on the red mite population before it disappears.
The mites that avoid any treatment once a house is emptied are capable of living for many months without having to feed again.
Early treatment will hit mites still inhabiting nest boxes and perches with the aim of breaking down the waxy cuticle that covers them.
Even those not killed by the treatment can be maimed, and will be less likely to be able to move back into a place of safety.
Find out more about the latest red mite treatments
Red mite populations should be monitored weekly following the restocking of the shed using mite traps or “check areas” throughout the house.
The results of these checks should be written down as they are undertaken and so become part of the flock’s management plan.
They will provide an indication that red mites could be moving back into the building and so can be tackled with spot chemical and insecticidal treatments or using dry powder products.
Spraying equipment being used on many units is often not delivering the detergent correctly.
Sprays may not be fine enough to achieve maximum coverage and so get into cracks and crevices that harbour red mite populations.
Sprays often do not have a filter attached and so product is being wasted.
Ineffective spraying fails to control the red mite therefore being expensive for the producer because the spray liquid ends up running down into the pit.
Specialised veterinary laboratories should test the efficiency of a product by conducting a resistance test before application.