Essential oils could be a future weapon in the battle
against red mite in layers.
Speaking to delegates at the WPSA meeting in Southport,
Merseyside, earlier this week,
University
of Newcastle researcher David George outlined promising results
in the search for a natural treatment against the parasite.
Red mite is a widespread problem with one recent survey
suggesting that 87% of units are infected and the estimated cost to
the EU industry in terms of treatment and loss of production is
€130m (£121m) every year.
"And there is the problem of resistance to what few products are
left available for use," said Dr George.
One possible solution is the use of plant-derived essential
oils, which is being investigated in a DEFRA-funded project
(MITeHEN). The first stage was to screen many different of
essential oils, such as lavender to narrow down the list.
"Screening identified two promising candidates, thyme and
pennyroyal
essential oils. And testing on hens has just been completed where
birds were sprayed with the oil at 16 weeks of age and then every
six weeks."
Results look promising and both were effective in controlling
the mites, results are to be published shortly.
However, Dr George concentrated on a related study which
addressed the potential concern that the essential oils would taint
the eggs.
Eggs were analysed for certain compounds, as well as a sniff
test by a panel. "We even immersed eggs for 24 hours in the
treatment solution to ensure there was no taint."
Analysis in the laboratory found no traces of compounds in the
eggs. "We were surprised as the equipment used to detect the
compounds is very sensitive."
However, sniff tests did find taint with the pennyroyal with
eggs having a foul smell. "This would have a negative effect on
consumers, therefore, pennyroyal looks unsuitable as a natural
treatment for red mite."
In contrast, there was no problem with the thyme oil. However,
he added that further analysis was needed to look in further
detail, including taste tests of cooked egg.
When questioned about practicalities of using essential oils, he
admitted that their effect is shortlived being volatile compounds,
and they were looking at ways of reapplying it.
"One option could be to incorporate the treatment into the
ventilation system, a bit like a plug-in air freshener.
"This could prove useful in targeting mites in areas that a
contact product could not."
Another benefit of essential oils is that they contain several
active ingredients, so resistance is less likely than with
synthetic products based on one active ingredient.
- The egg taint element of the project was funded by
BEMB with support from a
WPSA scholarship.