Mite-spotting - approaches for detection and quantification of Aculops lycopersici on tomato and a few findings along the way

Abstract: In recent years, Aculops lycopersici (Acari: Eriophyoidea) has occurred more frequently in tomato cultivation throughout Germany. Despite its devastating damage potential when infesting tomato greenhouses, usually no regular monitoring is conducted for this mite in practise. There are two main reasons for this. Growers have no convenient monitoring methods at hand, and secondly A. lycopersici does not occur as frequently as other pests as for instance Trialeurodes vaporariorum. In order to be put into practise, monitoring methods must be very efficient and easy to handle. This study aims to provide solutions for early detection suitable for tomato growers as well as detection and quantification methods for monitoring of population dynamics and spatial distribution on plants and within greenhouses for research purposes. Different methods are under investigation and will be presented. In a greenhouse trial it was shown that it was possible to detect A. lycopersici infestations with non-destructive fluorescence and reflectance measurements on plants. Also a sampling method with sticky stamps delivered promising results. Quantification was possible even at low infestation rates. A good correlation between counts on stamps and actual counts on plants was shown. Parallel to these methods plants were scored for A. lycopersici symptoms visible to the bare eye as a reference, a method typically used at first place by growers and advisors. The suitability of each method for detection and monitoring of the pest will be discussed. The effects of drought stress on A. lycopersici quantity and on the development of A. lycopersici induced plant symptoms were investigated in the same experiment.