Yeasts play an important role in nutrition physiology and host attraction of many Drosophila species, and associations with various yeast species are documented for several drosophilid flies. The pest Drosophila suzukii (Matsumura) has a predominant association with the yeast Hanseniaspora uvarum. However, research has not been conducted on the nutritional physiology of the yeasts associated with D. suzukii (spotted wing drosophila). Therefore, in this study, we determined whether dietary yeast was nutritionally relevant and whether yeast species closely associated with D. suzukii positively affected life-history traits. Our results confirm a crucial role of dietary yeast in the larval development and survival of D. suzukii. Furthermore, we found specific effects of the closely associated yeast species H. uvarum and Candida sp. on larval survival. Observations of the egg-laying behaviour of D. suzukii on cherry fruits artificially colonised with different yeast species revealed that the number of eggs laid increased on fruits colonised with Candida sp. and Saccharomyces cerevisiae.

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Thrips (Thysanoptera) are small insects that can cause huge problems in agriculture, horticulture, and forestry through feeding and the transmission of plant viruses. They produce a rich chemical diversity of pheromones and allomones and also respond to a broad range of semiochemicals from plants. These semiochemicals offer many opportunities to develop new approaches to pest management. Aggregation pheromones and plant-derived semiochemicals are already available in commercial products. We review these semiochemicals and consider how we can move away from using them mainly for monitoring to using them for control. We still know very little about the behavioral responses of thrips to semiochemicals, and we show that research in this area is needed to improve the use of semiochemicals in pest management. We also propose that thrips should be used as a model system for semiochemically mediated behaviors of small insects that have limited ability to fly upwind.

Yeasts play an important role in the life cycle and biology of the insect pest Drosophila suzukii (Matsumura), commonly known as the spotted wing drosophila (SWD). Adult and larvae of this species are known to feed and benefit from yeast in their diet. In addition, yeasts were found to be attractive to SWD and were repeatedly found to be associated with SWD. Among those, Hanseniaspora uvarum is the most commonly mentioned. The present study explores the chemical composition and the effects of three H. uvarum strains and five yeast species (Saccharomyces cerevisiae, Candida sp., Issatchenkia terricola, Metschnikowia pulcherrima and Saccharomycopsis vini) in the diet of SWD adults. The different yeast species used in this study influenced mortality, fecundity and ingestion by SWD females. Hanseniaspora uvarum and S. vini were preferably ingested and increased fecundity of SWD females. The intra-and extracellular concentrations of compounds, such as amino acids, carbohydrates, sugar alcohols and organic acids, produced or consumed by yeasts differed among the species. Knowledge of the interaction of different yeast species with SWD and specific differences in the profile of compounds of yeast can help to improve the development of control strategies against the insect pest by promoting the ingestion of attractand-kill formulations based on the combinations of yeasts and an appropriate insecticide. Keywords Fecundity • Hanseniaspora uvarum • Ingestion • Spotted wing drosophila • Yeast metabolites Key message • Naturally occurring yeasts play an important role in SWD development. • Mortality, fecundity and ingestion by SWD adults are influenced by the yeast species in their diet. • The concentrations of nutritional compounds in the fermentation broth of different yeasts vary due to differences in the methods they produce or consume compounds. • Chemical analysis of selected yeast cultures helps to understand the interaction between SWD and putative associated yeast species.

This review covers aspects of putting essential oil compounds to use either as allelochemicals that manipulate the host selection process of Thysanopteran pest species or as botanical insecticides that kill these pests. Thysanoptera (thrips) make an especially interesting case study in this field, because their increasing economic impact puts some urgency on the development of novel control strategies, especially strategies that incorporate natural compounds. Known facts about the host selection behaviour of thrips are briefly summarized, and methods for the evaluation of thrips responses to volatile and non-volatile plant compounds are outlined. Recent results on the search for attractive and repellent volatiles and for feeding and/or oviposition deterrent essential oil compounds are listed in detail and their potential for use in control strategies against thrips pests is discussed. An overview of plant essential oils used either for insecticidal spraying treatments of crops or for fumigation of crops in greenhouses or fumigation chambers completes the picture of bioactivities. Finally, an outlook on the perspectives for future control strategies against thrips pests is given, including thoughts on the direction of further research needed to fully evaluate the thrips control potential of plant essential oils.

Two constituents of essential oils, carvacrol and thymol, were tested for their effects on the feeding activity, oviposition preference and oviposition rate of Frankliniella occidentalis and Thrips tabaci. Given a choice between treated and untreated leaf discs, F. occidentalis avoided ovipositing on leaf discs treated with 1 or 0.1% thymol. In no‐choice experiments, 1 and 0.1% thymol and 1% carvacrol resulted in a reduced oviposition rate of F. occidentalis compared with the control. Both constituents caused a slight reduction of the feeding damage of F. occidentalis. 1 and 0.1% carvacrol had a pronounced deterrent effect on the oviposition site selection of T. tabaci. Both constituents served as anti‐ovipositants for both thrips species, albeit F. occidentalis was more affected than T. tabaci.

This study investigates behavioural responses of adult western flower thrips (Frankliniella occidentalis Pergande; Thysan., Thripidae) females to direct contact with repellent phenylpropanoid plant compounds (salicylaldehyde and methyl salicylate) applied on bean and cucumber leaves. The residence time of F. occidentalis females until take off was significantly shorter on bean or cucumber leaf discs treated with salicylaldehyde at 1% concentration compared with control leaf discs. A methyl salicylate (1%) treatment of cucumber resulted in shorter time periods until thrips took off the treated leaf discs compared with the control leaf discs. In a choice experiment thrips avoided to settle on a 1% salicylaldehyde treatment of bean and cucumber leaf discs for a maximum of 3 h, on a 1% methyl salicylate treatment for a 5-h period. Within a 24-h period neither the egg-laying nor the feeding activity of F. occidentalis was affected after salicylaldehyde application (0.1%, 1%) on bean or cucumber. In contrast, methyl salicylate (1%) applied on bean and cucumber significantly prevented thrips females from oviposition and reduced the percentage of damaged area caused by their feeding activity for 24 h. As olfactory repellent plant volatiles applied on crop plants may elicit diverse post-landing responses of F. occidentalis, short-and long-term effects should be considered when evaluating the factual applicability of secondary plant compounds in a successful thrips management strategy.