The influence of

1
The influence of time since last blood meal on
the toxicity of essential oils shown to be
acaricides for the poultry red mite, Dermanyssus
gallinae
Tegan Jade Smith, School of Agriculture, Food
Rural Development, Newcastle University, UK.
Email T.J.Smith_at_newcastle.ac.uk
Aim ? The aim of the current project was to
investigate the toxicity of essential oils to
poultry red mite (a serious pest of hens),
starved for varying periods, to test the
hypothesis that The toxicity of plant essential
oils to the poultry red mite is affected by mite
physiological condition.
Use of synthetic acaricides is hampered by pest
resistance product withdrawals
More research is needed to assess the potential
of plant essential oils as acaricides
Essential oils contain chemicals toxic to pests.
E.g. linalool from lavender
Lavender
Essential oils have been investigated for control
of the poultry red mite
Essential oil toxicity may be affected by mite
physiological condition
Methods ? 23 mites were placed in Petri dishes
with a filter paper impregnated with 0.21 mg/cm²
of essential oil from thyme, palmarosa, caraway
or juniper leaf. ? Mites used had been collected
3, 6, 10, 13, 17 or 20 days prior to experiments,
and stored for that period without food. Dishes
were left at 22C for 24 hours. ? mite
mortality in treatment dishes was corrected to
account for that in control dishes. Arcsin
square-root transformed data were analyzed by
ANOVA ( Tukey Tests).
Results
Conclusions ? There was a trend for the
acaricidal effect of all essential oils to
increase as mites were starved for long
periods. ? Essential oils may be effective as
acaricides, especially if used to treat between
flocks of hens (if the period between flock
removal and treatment is long enough).
Mortality of mites in tests (means
back-transformed). Within treatment means not
sharing a common letter are sig. different (P lt
0.05).
Poultry red mite
Acknowledgements This work was funded under
Newcastle University's 'Vacation Scholarship
scheme as part of MITEeHEN (a larger, Defra
funded study). Images used were sourced from the
following locations Insecticideamazon.com toy
miteprofesoraloca.vox.com superman
symbolcomicbookcloset.com lavenderalphazero.web
.aplus.net essential oilthebodyshop.com
poultry red mitegeorgiasouthern.edu Charlie
Brown studentwww.saddleback.edu.