Red mite… the battle continues
By BFREPA vice-chairman John Widdowson
It may be less than a millimetre in size but that most persistent of parasites, the red mite, has got to be the only thing that in fourteen years of free ranging has almost reduced me to tears of despair. It’s been little comfort either that my frustration to fully control this blood-sucking beast has probably been shared by nearly every commercial egg producer in the country… and the battle goes on.
When we first started with free range hens in 1990 it was in brand new buildings and with no secondhand equipment. Yet within months, flocks were soon playing host to a healthy population of mite. But controlling them in those days seemed relatively straightforward and we had a few successful years using Barricade, a product mainly aimed at the cattle sector for controlling flies but with a license for use on poultry. The results were stunning; mite dead within hours of contact with the chemical and no need to reapply for around three months or so. In fact one application at the beginning of the summer would often be sufficient to keep a house clear until cooler weather in the autumn played its part in reducing mite activity.
Yet Barricade was based on a pyrethroid compound which is one of the more common groups of insecticide. The active ingredient was cypermethrin, which is still available and, along with alpha-cypermethrin, still forms the basis of many red mite treatments. They may work on other farms but they are treatments that are no longer effective on this farm and I would be hesitant to spend money or time applying them. The fact is that red mite seem able to very quickly build up a resistance to chemical attack. This may be down to continually using one product or the fact that because of the practical difficulties involved with application, there will always be some mite that get a below-strength dose.
When cypermethrin no longer did the job for us we moved on to the next chemical group – for despite the array of trade names, there are in fact only three main groups. We had a couple of successful years using fenitrothion in the shape of Micromite which was an organophosphate. When this was withdrawn, as most of the OPs have been, many producers bemoaned its loss but for us it too had ceased to be effective. A switch to Ficam W which belonged to the carbamate group of chemicals gave us control for another two years before that also lost its punch. And even after a gap of several years, a return to any of these products failed to deliver and never once have we seen anything like the response we had from Barricade on those virgin mite in the early days.
So how do we now cope with our armoury so depleted? Well it has been a three-pronged strategy. Our terminal cleaning is much more thorough and it is essential that this once-a-flock opportunity is used to physically knock back mite numbers. Washing alone will not totally eliminate the problem but it will have a big impact and the mite population will be starting from a much lower base, meaning it should be many months before infestation levels build to a point where hens begin to suffer. I know now that in the past we were putting equipment back that was still carrying mite that were very much alive and kicking. A good example was the chain feeder trough, the lip of which makes an ideal habitat for mite. It’s a difficult area to target with the pressure hose so as we dismantle it now it goes straight into a trailer lined with a plastic sheet to form a ’bath’. The feed trough, complete with coupler-legs, is totally submersed before washing. Although I’ve been told that you cannot drown mite, I’m not so sure and it certainly flushes them out for they can be seen floating on the surface. As an added bonus, the trough and legs will be washed in half the time following their soaking.
Our second line of defence is built around making the equipment less habitable for the mite. Gone are the old wooden slatted floors which would get encrusted with muck offering the mite effective protection from the knapsack sprayer. While we find the new plastic variety still offers a hideaway at the joints, the mites’ living quarters has been vastly reduced. And when we put the feeder back together, a quick dip of the coupler-leg in a bucket of a powdered desiccant such as Mitex or Hemexsan will help keep them out of here for a few months at least. Another dead easy trick, and highly effective, is the very strategic use of Decimite. We have Jansen nests and the Astroturf mat is fixed to a batten that, when in position against the front wall of the nest, makes an ideal home for the mite. Well, spray the batten with Decimite at turnaround and my experience is it will remain a mite-free zone for the life of the flock.
None of these actions on their own will control the mite, but bring them all together and you start to make life very difficult for them. To use a well-worn phrase so often quoted by the Ranger vets, you’ll tip the balance back in favour of the birds.
Having washed the house down and done all we can to ensure the equipment is not mite-friendly, we take a belt-and-braces approach to treatment. That means a thorough application of an approved insecticide – at present we use the last remaining organophosphate licensed for use in this way - Actellic. With the house empty of birds this is the best chance there is for a really thorough application. We then liberally apply a powdered desiccant and what mite have survived the washing process are going to find life pretty tough. We have invested in equipment to apply both sprays and powders with ease but for those who don’t fancy the job there are contractors available who will carry out the service. In fact producers who have had Fossil Shield applied in this way claim that it remains effective for the life of the flock, a sort of one-stop mite treatment.
Once the birds are housed a careful eye is kept on mite numbers which will build if left unchecked. Our mainstay of control is based on the powdered desiccants, which have proved very effective in keeping mite out of nest boxes where they have the potential to cause spotting on eggs with subsequent down-grading. When it comes to the lip on the feed trough, it is not practical to target this with a powdered product nor do you want to be using an insecticide that could contaminate the feed. That means using one of the many non-toxic or naturally based products on the market. Poultry Shield is ideal and is very effective when targeted directly at the mite. With a specially adapted spray-head, treating the trough lip need not be a difficult task, although anyone fitting new equipment would be well advised to purchase trough that has done away with this mite trap.
We have not got the mite problem beaten but we have got the upper hand… for the moment at least!
