using predatory mites to control red mite€¦ · red mites enter the bottles, where the predatory...

NOVEMBER 2016RANGER 97

The problemRed mites are notoriously difficult to controlbut are known to have a significant impact onegg production. Hiding in cracks and crevicesduring the day, these parasites come out atnight to feed on the blood of hens. Thiscauses them significant discomfort and in thecase of large infestations can drive them outof nest boxes. They also irritate the skin ofworkers, whilst working in the house orhandling eggs.

Red mites are present in poultry houses allyear round, however summer is an especiallyproblematic time for red mites as the warmthencourages breeding. During summer themite’s lifecycle is only 7-8 days long, sopopulations can explode very quickly. Twomites can become 16000 in just 60 days. Eggsare laid around the house, from which larvaeemerge in 2-3 days. Following a series oflarval stages, the nymphs start to feed on thehens as they develop into adults. A hen can

Using predatory mitesto control red mite

Red mites can have significant performance, health and welfare effectson laying hens. This month the Ranger investigates the use of biologicalcontrol to address this pest. Three free range egg producers also sharetheir experiences of trialling the strategy on their farms.

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loose up to three per cent of her bloodvolume in one night, the result of up to 50Kmites feeding.

Blood loss can lead to anaemia and poorhealth status but the irritation caused can bejust as serious. Hens may not be able to sleepand become stressed; the incidence of vicesincreases and egg production is affected. Thefeeding mites can also transmit bacterial andviral infections, increasing veterinary costs.

The severity of the infestation depends on thetype of housing, age of buildings and thecontrol methods used. Older woodenbuildings are known to be particularlyproblematic as red mite colonies becomeestablished over time. There can also besignificant issues in muti-tier units as thereare many places for red mites to hide and itcan be difficult to get rid of them.

Current solutionsThere are a number of products to control redmites on the market. The number ofinsecticides available to use is diminishing asthe chemicals are withdrawn from the marketover safety concerns. Resistance is also a huge

problem, particularly if a farm has beentreated regularly for a number of years. Ashuttle programme is recommended, alongwith the use of alternative control measures.Certain products can be used as spottreatments during the cycle and others atturnaround.Diatomeceous earth or silica-based productsare often used – they create a barrier, whichthe mites won’t cross. The razor sharp edgesof the diatom damage the exoskeleton of themites, whereas silica causes death bydehydration. These products need to beapplied with appropriate personal protectionand according to the manufacturer’sguidelines.

Cleaning at turnaround is also important asthe mites can survive in an empty house forup to ten months. It is, however, almostimpossible to entirely rid all cracks andcrevices from all mites and their eggs. Strictbiosecurity during the cycle will help toprevent the spread of the mites or their eggsbetween houses.

Due to their short lifecycle it is impossible tokill all the mites in one treatment. This is

During summer the mite’s lifecycle is only 7-8 days long,so populations can explode very quickly



where regular monitoring and a programmeof different control measures come into theirown. The use of natural products as miterepellents has been studied including; garlic,orange, neem and thyme essential oils; someof which are employed by small scale andorganic producers. Other novel controlmethods being investigated are vaccinationand destabilising the mite’s symbioticbacteria.

Biological controlBiological control can be defined as the use ofa natural enemy in order to control a pestpopulation. Natural enemies of insect pestsinclude, predators, parasitoids andpathogens. There are certain species of mitethat feed on and kill red mites. Thesepredatory mites however, do not feed onhens or cause them any problems. Since theirdevelopment is slower and because they arenot as resilient as red mites, mite predatorswill need to be reintroduced after turnaroundand a few times during the flock.

APPI is a daughter company of TheNetherlands based Koppert BiologicalSystems, which has been offering biologicalcontrol solutions against pests of glasshouses

and soft fruit in the UK since the early 80’s.Working for Koppert, Damien Morel, a Frenchentomologist, started focusing on pestcontrol for the companion and livestockanimal market in 2012. Driven by his passionfor animals and natural pest control, heidentified and started experimenting withvarious candidate mites, that naturallypredate the red mite.

The obvious and widely available Hypoaspisspecies was trialled, but two other specieswith greater effectiveness and resilience inthe poultry house were identified soon after.This led to the commercial rearing of Androlisand Taurrus mites. Both species areindigenous to the UK, being found in wildbird’s nests. Androlis prefers a dampenvironment and can be found in the litter ormanure. It kills both eggs and larvae, runningand hunting the later for up to 1.5 metres.Taurrus doesn’t move very far from therelease site and has a clear preference foradult and nymph stages. These mites like adrier environment and are usually spread inand on top of the nest boxes. Scientists atAPPI have been researching how, where andwhen to release the predatory mites in orderto achieve optimal control of red mites. This

Tarrus mite predating a red mite



has provides them with the knowledge tocreate release protocols for flat-deck andmulti-tier systems.

Currently the company has over 250 clients inFrance, Switzerland, The Netherlands andItaly. Jeroen Koppert is the salesrepresentative for the UK, “we introduced theconcept at this years Pig and Poultry fair andare pleased to now be working with anumber farmers in the UK as a result.” Heexplained that the key to success withbiological control was to use it as apreventative strategy.

“Often producers wait until they have a bigproblem before taking action,” Jeroen said.“We would suggest formulating a control planbased on preventive action before the start ofeach flock since strategically appliedbiological control has the potential topermanently keep the red mite numbersdown.” He explained that the financialbenefits of controlling red mite populationsare somewhat underestimated, “an early dropin laying, caused by stress from red mite bites,has a ripple effect on production throughoutthe rest of the flock.”

Predatory mites have a slower life cycle thanred mites so it is important to introduce theminto the flock early. “We recommended thatthey are released into multi-tier units a fewdays following placement,” explained Jeroen.“For flat-deck houses we do the firsttreatment six to eight weeks after the hens goin.” He highlighted the fact that even if youdon’t see red mites at the start, they are there.For a complete control strategy it’s importantnot to use a residual or toxic chemicaltreatment, as it will also kill the predatorymites. “Silica products would also kill thembut the amount of dust in the poultry houserenders it ineffective after about eight weeks,”Jeroen said.

“We approach biological control as part of anIntegrated Pest Management (IPM) strategy,”he went on. This incorporates multiple toolsto achieve optimal control of red mite.“Together with frequent release of predatory

mites, knock-down products such as PoultryShield or APPI’s organic black soap are goodsolutions for spot control of red mite clusters.”

Predatory mitesThe biological control agents ANDROLIS PRO®and TAURRUS PRO® are commerciallyavailable to poultry farmers. These two miteshave different predatory behaviours, acting ina synergistic and complementary way to killthe parasites. “In a flat deck house, we wouldseed the nest boxes with the Taurrus mitesand spread the Androlis mites in the manure,”explained Jeroen. “There are lots of eggs inthe manure for them to feed on as the redmites spread their eggs as they return fromfinishing a blood meal.” Additionally Androlis

Tarrus mite


105NOVEMBER 2016RANGER

is supplied in sustained release bottlesfunctioning as an ‘attract and kill’ system, tobe attached to the aviary structure. Bycreating an attractive habitat with bran, thered mites enter the bottles, where thepredatory mites are living, and are killed.

“This is the way we release Androlis in muti-tier units, as the muck is being removedregularly,” he went on. “We place one bottleper 150 hens evenly distributed over thestructure, targeting particular areas where redmite is found.” They can also be positionednear perches or the egg belt. “Temperatureand humidity have a big effects ondevelopment of the red mite,” stated Jeroen.“We would recommend four to five releasesper flock and some knock down treatmentsmay be needed over the summer.” A Taurrusmite will survive for eight weeks and theAndrolis a little less.

The effects of red mites are oftenunderestimated, as it is difficult to accuratelydetermine how many there are. However,visual monitoring remains an important partof the biological control strategy. Theconcept is particularly attractive to those witha historical red mite issue and is approved fororganic systems.

In order to familiarise the UK market withbiological control, APPI is working withthree BFREPA producers. “Every situation isdifferent so we are learning from each farmwe work on,” Jeroen said. “We make acontrol plan specifically for each producer,working with them throughout the flock.”Performance will be judged compared toother houses on each farm, in terms of redmite populations and the need to useinsecticides.

Trevor SellersTrevor has been producing free range eggs

since 1988 and bought his farm in Rutland in2004. He has two Harlow wooden flat-deckhouses, one holding 12,000 and the other8,000 hens. “One house was built 20 years agoand the other 30,” explained Trevor. “Thismeans that resistance has built up to several

chemicals, whilst others have beenwithdrawn from sale.” For the last three yearshe has sprayed a diatomeceous earth productat turnaround. “I find that this lasts for around20 weeks, depending on the temperature ofthe house,” said Trevor. “After that althoughthe product is still there, the mites walkaround it and we have to start spraying withinsecticide.”

Being previously involved in organic

Androlis is supplied in sustained release bottlesfunctioning as an ‘attract and kill’ system, to be attachedto the aviary structure.



production Trevor had heard of biologicalcontrol. “Other producers had used parasiticwasps to control flies with success,” he stated.“So when I talked to Jeroen at the Pig andPoultry fair I was very interested in theirproduct for red mite.” Trevor started a trialwith predatory mites in June, the firstintroduction was carried out when the henswere 28 weeks old. “It is at this point that wewould start to see signs of red mite in thehouse, meaning there are enough for thepredatory mites to feed on,” he explained.

Following the first release the predatory miteshad pushed the red mites up above the nestboxes. “We were advised to carry out acorrective action by spraying these colonieswith Poultry Shield,” Trevor stated. “Thisreduced the population, enabling thepredatory mites to control them more easily.”

The next stage involved attaching sachets ofthe predatory mites near the nest boxes,allowing them to crawl out. “We have justcarried out this second release at 40 weeks,”Trevor said. “Depending on how this goes, wewill decide if we need to carry out anothertreatment.” He discussed how he was pleasedto be involved in testing this new method butit would take at least six months to get a truepicture. “For me the advantage is that it is safefor both humans and chickens,” stated Trevor.“ I’ve been happy with the results so far andam looking forward to seeing the outcome atthe end of the flock.”

Charlie Stephenson“Everyone in the industry suffers with redmites,” stated Charlie. “We endeavor to ensurethat the problem does not get out of controlbecause of the detrimental effect that a largemite population can have on bird welfare.” Hestressed the importance of terminal hygieneand pest control at turnaround. After placingCharlie regularly monitors the mite

populations and in order to maintain control,he sprays with insecticide when necessary. Itis well understood that red mite populationscan multiply rapidly in the right conditions.Charlie has five free range units on his farm isWest Yorkshire, two of which are part of thetrial. “The first release was carried out at 22weeks, in one flat deck and one multi-tierhouse,” Charlie said. “They carried out thesecond release a few weeks ago and the planis for us to do three in total.”

“The product has been easy to use and we’vebeen pleased with the backup provided,” heexplained. “However, the results are underreview and we will have wait until the end ofthe flock before the outcome can beascertained.” Charlie hasn’t had to use aninsecticide yet but said that it wasn’t a simpletask to get the right balance between the redand predatory mite populations. “Theprinciple of biological control is good but ifthe predators are too successful, then theydon’t have anything to feed on,” he said. “Thismeans repeat introductions, the cost of whichcould be prohibitive.” Charlie plans to keepworking with this method as long as it iskeeping the red mite populations in check.

Charlie had a problem with flies over thesummer but couldn’t use a chemical solution,as it would have killed the predatory mites.“Instead we released parasitic wasps, suppliedby APPI,” he explained. “This worked verywell!”

Doug WanstallDoug agreed with the other producers thateveryone in the industry has an issue with redmite. “We have red mite on all our sites,” heconfirmed. “However, there are differences inthe severity of infestation. I have seenproduction drop by 10-15% overnight due toan explosion in the red mite population.”Doug explained that they had tried every


109NOVEMBER 2016RANGER

product on the market for red mite. “I wasinterested in testing biological control as it isa good fit with our business model,” he stated.“We want to build resilience into our businessand one thing to avoid, is building upresistance to chemicals. Reducing sprayingalso has benefits for staff.”

“Currently we spray with Ficam W twicebefore the hens are placed in the houses,” heexplained. “Then we use diatomeceous earthin the litter and silica products in red mite hotspots.” Doug believes that a multi-prongedattack is necessary to control this pest. “Beingbased in Kent, there are a lot of glasshouses,”he described. “Several of our neighbours usebiological control products so I was aware ofAPPI.”

Doug is testing biological control in four ofhis flat-deck houses, which are spread overthree sites. The current trial was started mid-way through the flock. “Results were slow tosee and we have had to do spot applicationswith Mite-Max,” he explained. “However, oncethat was done and more predatory mitesintroduced, we seem to have got on top ofthe problem.” Doug found the product wasfairly easy to use, although attaching all thebottles took a while, “after that the predatorymites get on with their work while we doours!”

Doug’s confidence in the product means thathe is about to start using biological control intwo more units from the start of the flock.“This means that we won’t be able to useFicam,” he cautioned. “The birds are going innext week and we’ll do the first introductiontwo weeks later.”

A useful weaponWhilst the concept of biological control mayseem alien to some, it is in fact a widely used

method in other areas of agriculture. As wellas its application in glasshouses and orchards,it is also becoming a more common methodfor the control of flies.

The potential effect of red mites on birdwelfare as well as a producer’s bottom lineshould not be ignored. Breaking the cycle ofre-infection is key to controlling red mitepopulations. Whilst it is impossible toeradicate them entirely, the aim should be toget numbers down to an acceptable level.“We would expect that the red mite pressurewould decrease by using predatory mitesover multiple flock cycles,” enthused Jeroen.“The opposite is true with insecticides, withresistance building up following repeateduse.”

The trials described will run for one or moreflocks with each of the producers. The Rangerwill look forward to catching up on progressat these test farms in the New Year to find outhow biological control fairs in a variety of freerange production systems.

Both Jeroen Koppert and entomologistDamien Morel will be present on the APPIstand at the BFREPA conference to answerany questions producers have about thebiological control of red mites or flies.

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using predatory mites to control red mite€¦ · red mites enter the bottles, where the predatory...

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