Effect of plant essential oils as acaricides against the poultry red mite, Dermanyssus gallinae, with special focus on exposure time

Essential oils from thyme and cade have been shown to be effective acaricides against the poultry red mite, Dermanyssus gallinae (De Geer) when tested over a 24. h period. Data on the actual rate of knock-down achieved with these products is lacking and potentially important as essential oils are likely to display only short-term toxicity. When tested over periods of less than 24. h, thyme essential oil killed D. gallinae relatively quickly and so may make for an effective acaricide even if the residual toxicity of this product is low. However, cade essential oil did not display such a high level of mite knock-down, suggesting it may hold less promise in D. gallinae management. Comparison of the results with those obtained elsewhere using alternative D. gallinae products further confirms the possibility that thyme essential may be useful in control of this pest. This might be especially true if thyme essential oil were employed as part of an integrated pest management approach.