Vine weevil, Otiorhynchus sulcatus F. (Coleoptera: Curculionidae), is an economically 20 important pest species in many soft-fruit and ornamental crops. Economic losses arise from 21 damage to the roots, caused by larvae, and to the leaves, caused by adults. As adults are nocturnal and larvae feed below ground, infestations can initially be missed, and controls 23 may, as a result, be applied too late. In the absence of a vine weevil sex or aggregation 24 pheromone being identified, the development of an effective semiochemical lure for better 25 management of this pest is likely to focus on host-plant volatiles. Here, we investigate the 26 electrophysiological and behavioral responses of adult vine weevils to volatile organic 27 compounds (VOCs) originating from their preferred host plant Euonymus fortunei, and 28 synthetic VOCs associated with this host when presented individually or as blends. 29 Consistent electroantennographic responses were observed to a range of generalist VOCs. 30 Behavioral responses to VOCs, when presented individually, were found to be influenced by 31 the concentration of the compound to which the weevils were exposed. Vine weevil adults 32 showed directional movement towards a mixture of seven plant volatiles (methyl salicylate, 33 1-octen-3-ol, (E)-2-hexenol, (Z)-3-hexenol, 1-hexanol, (E)-2-pentenol, and linalool) even 34 though either no response or negative responses were recorded to each of these compounds 35 when presented individually. Similarly, vine weevils showed directional movement towards a 36 1:1 ratio mixture of (Z)-2-pentenol and methyl eugenol. Results presented here point to the 37 importance of blends of generalist compounds and concentrations of VOCs in the 38 optimization of a lure.

Saddle gall midge, Haplodiplosis marginata (von Roser) (Diptera: Cecidomyiidae), is a sporadic pest of cereals in Northern and Central Europe and is of increasing importance in the UK. Recently, the major component of the sex pheromone produced by adult female H. marginata was reported to be 2‐nonyl butyrate. The importance of absolute configuration on attractiveness, the effects on trap catches of the addition of minor pheromone components, dispenser type, and pheromone loading are described in the development of an optimised pheromone lure with which to trap H. marginata males. In analyses of volatiles collected from virgin female H. marginata by gas chromatography (GC) coupled with electroantennographic recording (EAG) from the antenna of a male H. marginata, two EAG responses were observed. Analyses by coupled GC‐mass spectrometry (MS) indicated these were due to 2‐nonyl butyrate and a trace amount (1%) of 2‐heptyl butyrate. A similar trace amount of 2‐nonanol was detected in GC‐MS analyses but this compound did not elicit an EAG response when the synthetic compound was tested, whereas the other two compounds did. These three compounds were not observed in collections of volatiles made from male H. marginata. The 2‐nonyl butyrate was shown to be the (R)‐enantiomer. In field trapping tests (R)‐2‐nonyl butyrate was at least 10× more attractive to male H. marginata than the racemic compound, and the (S)‐enantiomer was unattractive. Addition of the potential minor components individually or together at the naturally occurring ratios did not increase or reduce the attractiveness of the lure. Polyethylene vials and rubber septa were equally effective as pheromone dispensers, lasting for at least 5 weeks in the field in the UK, although laboratory tests indicated release from the former was more uniform and more likely to last longer in the field. Increasing loading of pheromone in the dispenser increased attractiveness. Traps baited with polyethylene vials containing 0.5 mg of (R)‐2‐nonyl butyrate are recommended for monitoring H. marginata and these are far more sensitive than water or sticky traps currently used for monitoring this pest.

14Saddle gall midge Haplodiplosis marginata (Diptera: Cecidomyiidae) is a pest of cereals

Degree-day based phenological forecasting model of saddle gall midge (Haplodiplosis marginata)

Saddle gall midge (Haplodiplosis marginata) is a cereal pest exhibiting sporadic outbreaks for which chemical control options are limited. Integrated Pest Management programs may offer a means of suppressing H. marginata outbreaks, reducing pesticide input. Many IPM programs benefit from the natural population suppression inflicted through predation and parasitism. The larval stage of H. marginata overwinters in the soil and may be preyed upon by ground-dwelling arthropods, however the natural enemies of H. marginata remain unrecognized. A PCR-based assay for detecting H. marginata in the guts of predators was designed using novel species-specific primers. Feeding trials involving H. marginata larvae showed a detectability half-life of 31.07 hours post-feeding in Nebria brevicollis. The guts of field-caught Carabidae were screened for H. marginata DNA. Four species: Poecilus 2 versicolor, Nebria brevicollis, Harpalus rufipes and Loricera pilicornis were identified as natural enemies of H. marginata for the first time. A higher proportion of positive results were obtained at the end of H. marginata emergence (July) compared to the beginning (May). The importance of understanding trophic interactions in the management of H. marginata is discussed in addition to the potential uses for the newly designed assay and primers.