The Asian long-horned beetle (ALB),Anoplophora glabripennis(Motschulsky), is a highly polyphagous invasive pest with a broad range of host species, but showing relevant differences between infestation areas. Host preference and host colonization (female fecundity, egg and larval survival) were assessed in a population in Northern Italy by choice and no-choice experiments conducted in both field and laboratory conditions. During 5 years of field observations, ALB was found to infest seven genera of trees:Acer, Aesculus, Betula, Populus, Prunus, SalixandUlmus. However,Acer, Betula, UlmusandSalixresulted to be the preferred hosts corresponding to 97.5% (1112) of the 1140 infested trees. In both laboratory and field trials carried out on these four host genera, no-choice experiments recorded the highest host colonization ofA. glabripennisonAcertrees, with the highest number of laid eggs and the lowest egg and larval mortality.UlmusandSalixshowed a lower number of laid eggs during laboratory choice test, but egg and larval mortality had mean values similar toAcer. On the contrary, despite the high number ofBetulatrees felled during the eradication plan carried out in the infestation area, this tree species showed the lowest beetle suitability in terms of number of laid eggs and insect survival. An overestimation of the number of infestedBetulaoccurring during the tree survey may explain the discordance between high number of infestedBetulaand low beetle suitability. Instead, the large number of infestedAcerrecorded in the field was probably due to the high abundance of these trees occurring in parks and gardens within the infestation area and to the low adult dispersal ofA. glabripennis. Overall, results from this study confirm that host species affects both beetle colonization and breeding performance. The study shows ALB host preference and host suitability varying between tree species, suggesting an ALB acceptance even of sub-optimal hosts.

In this study, we present the first characterization of herbivore-induced plant volatiles (HIPVs) released from infested olive leaves. The gall midgeDasineura oleaeis a specific pest ofOlea europaeaand endemic of the Mediterranean Basin, an area in which severe outbreaks currently occurred. Little is known about the damage caused by the pest and the relationship with its host. Since gall formation and larval feeding activity may lead to the release of specific plant volatile compounds, we investigated the volatile profiles emitted from infested plants compared with healthy plants under both laboratory and field conditions. Additionally, the volatiles emitted from mechanically damaged plants were considered. A blend of 12 volatiles was emitted from olive trees infested byD. oleae. Of these, β-copaene, β-ocimene, cosmene, unknown 1 and unknown 3 were found to be exclusively emitted in infested plants. The emission of germacrene-D, (E,E)-α-farnesene, and (Z,E)-α-farnesene, α-copaene, (E)-4,8-dimethylnona-1,3,7-triene, (E)-β-guaiene and heptadecane significantly increased in infested trees. Linalool, β-copaen-4-α-ol, β-bourbonene, β-cubebene, β-elemene, β-copaene and δ-amorphene were found only in the field trial and showed differences depending on the level of infestation and the plant stage. (Z)-3-Hexenol, (E)-4-oxohen-2-enal, and 2-(2-butoxyethoxy)-ethanol, were exclusively emitted from the leaves after mechanical damage. In a field trial in Italy, we also demonstrated spring synchronization between adults ofD. oleaeandO. europaeatrees. Analyses of morphoanatomical malformations of gall leaves showed that tissue alterations occur at the spongy parenchyma causing an increase of the leaf blade thickness. We speculate that tissue alterations may lead to HIPV release, in turn potentially attractingD. oleaenatural enemies.

Studies were conducted during the period 2019/2020 to evaluate the effectiveness of four lures for codling moth (Cydia pomonella L.) in pome fruits in Italy and the USA. Multi-component blends of sex pheromone ((E,E)-8,10-dodecadien-1-ol, PH), pear ester ((E,Z)-2,4-ethyl decadienoate, PE), (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT), and pyranoid linalool oxide (6-ethenyl-2,2,6-trimethyloxan-3-ol, LOX) were loaded in either a halobutyl elastomer septum or a PVC matrix and always used in combination with acetic acid (AA) loaded in a closed membrane co-lure. Total moth capture was significantly greater with the PVC than the septum lure loaded with PH/PE + AA in both countries. Female capture in the USA study was significantly greater for 8 weeks in traps baited with the PE/DMNT/LOX blend + AA co-lure than with other lures and adding PH to this blend in a PVC lure significantly reduced female capture. In contrast, female capture in Italy did not differ among lures and counts were similar in both apple and pear crops treated with or without mating disruption. These results suggest that the effectiveness of ‘female removal’ strategies to manage codling moth may be geographically limited and further comparisons are needed in other production regions and in walnut.

Chemical control of Drosophila suzukii (Diptera: Drosophilidae) based on the use of insecticides is particularly challenging as the insect attacks ripening fruits shortly before harvest. An alternative strategy may rely on the use of yeasts as phagostimulants and baits, applied on canopy as attract-and-kill formulations. The aim of this research was to identify the most attractive among six yeast species for D. suzukii: Saccharomyces cerevisiae, Hanseniaspora uvarum, Clavispora santaluciae, Saccharomycopsis vini, Issatchenkia terricola, and Metschnikowia pulcherrima. The volatile profile of C. santaluciae was described for the first time. Behavioural experiments identified H. uvarum and S. vini as the most attractive yeasts. The characterization of yeast headspace volatiles using direct headspace (DHS) and solid-phase microextraction (SPME) revealed several strain-specific compounds. With DHS injection, 19 volatiles were characterised, while SPME revealed 71 compounds constituting the yeast headspace. Both analyses revealed terpenoids including β-ocimene, citronellol, (Z)-geraniol (nerol), and geranial as distinct constituents of S. vini. H. uvarum and S. vini were further investigated using closed-loop stripping analysis (CSLA) and electroantennography. Out of 14 compounds quantified by CSLA, ethyl acetate, isoamyl acetate, β-myrcene, benzaldehyde and linalool were detected by D. suzukii antennae and might generate the strong attractiveness of S. vini and H. uvarum. Our results highlight a strong attraction of D. suzukii to various yeasts associated with both the flies and their habitat and demonstrate how different sampling methods can impact the results of volatile compound characterization. It remains to be demonstrated whether the distinct attraction is based on special adaptations to certain yeasts and to what extent the metabolites causing attraction are interchangeable.

Seventeen trials were conducted using traps baited with kairomone‐based lures to evaluate female removal (FR) as an effective management tactic for codling moth, Cydia pomonella, L., in organic pear, Pyrus communis L., production in Italy and USA during 2019–2020. Studies included paired plots (0.4–1.4 ha) treated with or without 60 traps ha⁻¹ in cultivars Bartlett and Abate Fétel. Paired plots were also treated together with or without mating disruption (MD) and with similar spray programmes. Three‐, four‐, and five‐component lures were used with several trap types: green, clear or green/white bucket traps and orange delta traps. The three‐component lure consisted of (E,E)‐8,10‐dodecadien‐1‐ol (sex pheromone, PH), (E,Z)‐2,4‐ethyl decadienoate (pear ester, PE) and acetic acid (AA); the four‐component lure was PE, (E)‐4,8‐dimethyl‐1,3,7‐nonatriene (DMNT), 6‐ethenyl‐2,2,6‐trimethyloxan‐3‐ol (pyranoid linalool oxide, LOX), and AA, and the five‐component lure had PH added. Preliminary studies were also conducted to evaluate the trapping efficacy of non‐saturating bucket traps. A clear bucket trap baited with PE/DMNT/LOX + AA captured 97‐fold more codling moth females than an orange delta trap baited with PH/PE. However, female captures did not differ between traps when both were baited with the four‐component lure. Fruit injury from codling moth was significantly reduced with the implementation of FR in both pear production regions. At harvest, mean fruit protection in the USA studies was 65% and 27% in Italy. This difference was likely associated with the four‐component lure being less effective in Italy than in the USA. Nevertheless, results demonstrate that FR can be a useful approach to remove females immigrating into orchards and as a new tactic to reduce pest pressure in selected areas of orchards allowing both MD and organic insecticide programmes to be more effective. Further studies should investigate the cost‐benefit of matching the intensity of FR to variable pest pressures.

Ips typographus, the European spruce bark beetle, is a destructive forest insect that attacks spruce trees. It poses a significant threat to the forestry industry, causing widespread tree mortality and economic losses, and its management through chemical ecology is a promising approach. Attraction relies on aggregation pheromones while repellency is achieved via antiaggregation pheromones combined with mixtures of nonhost volatiles (NHVs), but an effective push and pull strategy has not been established yet. In this study, we observed the beetle colonization dynamic and density comparing pure Norway spruce stacks and Norway spruce stacks with 20% Scots pine logs. We collected the spruce bark volatiles before the beetle colonization and at the end of the trial, and tested the behavioral effects on the beetles of both spruce and pine essential oils in olfactometer trials. In the stacks with Scots pine, we observed a delayed primary colonization and a 65% reduction of the secondary colonization, confirming the colonization disruption mediated by NHVs. Volatile analysis showed a significant change in the bark emission profiles, and the reaching of the antiaggregation phase was marked by the release of verbenone. Behavioral experiments confirmed the attractivity of spruce essential oil and the strong repellency of the pine essential oil. The study supports the use of complex NHVs blends for the beetle behavioral manipulation in the field. Further studies are needed to assess if the same results can be achieved by deploying essential oils in forest stands.