The first host plant dataset of Curculionidae Scolytinae of the world: miscellaneous Tribes.

Tribes Coriacephilini, Corthylini, Cryphalini, Ernoporini, Trypophloeini, Xyloctonini, and Xyloterini (Coleoptera: Curculionidae; Scolytinae) include spermophagous, phloeophagous, and xylomycetophagous species. Besides direct damage caused by burrowing into host plant tissues, some species are vectors of aggressive pathogens causing plant dieback and death, with consequent economic and ecological relevance. The international trade in plants and wood products is one of the main pathways for the introduction of non-native species worldwide. In this context, data availability on host plants and their economic uses is essential in pest risk assessment and for planning effective detection and monitoring strategies against invasive species. This paper provides a complete and updated list of host plants, with economic categorization, for 2139 scolytine species.

The first full host plant dataset of Curculionidae Scolytinae of the world: tribe Xyleborini LeConte, 1876.

Xyleborini is the largest tribe of Scolytinae accounting for about 1300 species worldwide; all species are primarily xylomycetophagous, developing on symbiotic fungi farmed in plant woody tissues. Xyleborini wood-boring action, associated with the inoculum of symbiotic fungi, can lead, sometimes, to the emergence of host plant dieback, wood damage and death; for this reason, multiple Xyleborini are major pests on both cultivated, forest and ornamental trees. Many Xyleborini are invasive worldwide and great effort is expended to manage their biological invasions or prevent new arrivals. Imports of host plants often have a primary role as a pathway for introduction and are frequently responsible for the establishment of species in non-native environments. In this context, data availability on Xyleborini host plants is a major limiting factor in the development of effective detection and monitoring strategies as well as a fundamental variable to consider in risk assessment of plant pests and invasive species. This contribution provides updated host records and the hosts economic categorization for the 1293 Xyleborini known worldwide to date.

New species and new records of exotic Scolytinae (Coleoptera, Curculionidae) in Europe.

Background: Bark and ambrosia beetles (Coleoptera, Scolytinae) are amongst the most important wood-boring insects introduced to Europe. During field investigations conducted between 2019 and 2021 in different countries and regions of Europe, many exotic species have been recorded providing new and relevant data. New information: Dryoxylononoharaense (Murayama, 1933) is recorded in Europe for the first time. Xyleborinusattenuatus (Blandford, 1894) is a species new to Italy, while Xylosandrusgermanus (Blandford, 1894), Hypothenemuseruditus (Westwood, 1836) and Amasa sp. near A.truncata are new country records for Portugal. Cnestusmutilatus (Blandford, 1894), Phloeotribusliminaris (Harris, 1852) were collected in Italy and Amasa sp. near A.truncata was collected in France after the first discovery, confirming their establishment and their dispersal into new areas.

Successful Eradication of the Asian Longhorn Beetle, Anoplophora glabripennis, from North-Eastern Italy: Protocol, Techniques and Results.

The Asian Longhorn Beetle (ALB), Anoplophora glabripennis (Coleoptera: Cerambycidae), is an important and extremely polyphagous wood-boring beetle native to Asia. In the 1990s, ALB was accidentally introduced into North America and Europe. In 2009, a large ALB infestation was found in the Veneto Region (north-eastern Italy), in the municipality of Cornuda (Treviso province). Eradication actions were immediately undertaken, based on delimitation of infested and buffer zones, tree visual inspections, felling and chipping of infested trees, trapping protocols, and citizen alerts. A total of 36,361 trees, belonging to 16 genera, were surveyed twice a year over an area of 7594 hectares. In 2020, after 11 years of eradication measures, the ALB population of Cornuda was declared eradicated. Overall, 2361 trees belonging to 8 genera were felled and destroyed, of which 1157 were found to be infested by ALB. This paper describes all the actions carried out and the procedures applied in order to eradicate ALB from north-eastern Italy, providing a useful example for current and future ALB eradication programs.

Improved Light Traps for Early Detection of Insect Pests of Phytosanitary Concern in Shipping Containers.

The number of introductions of alien insect has been increasing in the last decades, primarily transported in shipping containers. The attraction of light of different wavelengths (white, infrared, ultraviolet, and red) applied on sticky traps was tested for the development of new traps for hitchhiker insects. The addition of entomological glue and insecticide on the trap was also tested. Tests were conducted on Cadra cautella Walker (Lepidoptera: Pyralidae), Drosophila melanogaster Meigen (Diptera: Drosophilidae), Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and released inside a shipping container. In the first test, one light color at a time was tested setting eight traps in the container, one for each possible combination of the variables: light on or off, glue added or not, and insecticide sprayed or not. In the second, five traps were used, all of them coated with the entomological glue: one for each light color and one with light off as control. In all the single color tests (except for infrared), light-on traps captured more, except for T. castaneum that was not attracted to white. In the multi-color test, C. cautella showed no preference among white, ultraviolet, or red; Drosophila melanogaster preferred ultraviolet and white over red; and beetles had a much greater attraction to red. Lastly, the stronger entomological glue improved catches of beetles, whereas insecticides did not. In conclusion, results suggest a possible application of sticky light traps against hitchhiker insects and further studies should verify if the simultaneous use of different light colors can improve the trap performance and does not act as a repellent.

Response of native and exotic longhorn beetles to common pheromone components provides partial support for the pheromone-free space hypothesis.

Longhorn beetles are among the most important groups of invasive forest insects worldwide. In parallel, they represent one of the most well-studied insect groups in terms of chemical ecology. Longhorn beetle aggregation-sex pheromones are commonly used as trap lures for specific and generic surveillance programs at points of entry and may play a key role in determining the success or failure of exotic species establishment. An exotic species might be more likely to establish in a novel habitat if it relies on a pheromone channel that is different to that of native species active at the same time of year and day, allowing for unhindered mate location (i.e., pheromone-free space hypothesis). In this study, we first tested the attractiveness of single pheromone components (i.e., racemic 3-hydroxyhexan-2-one, racemic 3-hydroxyoctan-2-one, and syn-2,3-hexanediol), and their binary and tertiary combinations, to native and exotic longhorn beetle species in Canada and Italy. Second, we exploited trap catches to determine their seasonal flight activity. Third, we used pheromone-baited "timer traps" to determine longhorn beetle daily flight activity. The response to single pheromones and their combinations was mostly species specific but the combination of more than one pheromone component allowed catch of multiple species simultaneously in Italy. The response of the exotic species to pheromone components, coupled with results on seasonal and daily flight activity, provided partial support for the pheromone-free space hypothesis. This study aids in the understanding of longhorn beetle chemical ecology and confirms that pheromones can play a key role in longhorn beetle invasions.

Maximizing Bark and Ambrosia Beetle (Coleoptera: Curculionidae) Catches in Trapping Surveys for Longhorn and Jewel Beetles.

Bark and ambrosia beetles are commonly moved among continents within timber and fresh wood-packaging materials. Routine visual inspections of imported commodities are often complemented with baited traps set up in natural areas surrounding entry points. Given that these activities can be expensive, trapping protocols that attract multiple species simultaneously are needed. Here we investigated whether trapping protocols commonly used to detect longhorn beetles (Coleoptera: Cerambycidae) and jewel beetles (Coleoptera: Buprestidae) can be exploited also for detecting bark and ambrosia beetles. In factorial experiments conducted in 2016 both in Italy (seminatural and reforested forests) and Canada (mixed forest) we tested the effect of trap color (green vs purple), trap height (understory vs canopy), and attractive blend (hardwood-blend developed for broadleaf-associated wood-boring beetles vs ethanol in Italy; hardwood-blend vs softwood-blend developed for conifer-associated wood-boring beetles, in Canada) separately on bark beetles and ambrosia beetles, as well as on individual bark and ambrosia beetle species. Trap color affected catch of ambrosia beetles more so than bark beetles, with purple traps generally more attractive than green traps. Trap height affected both beetle groups, with understory traps generally performing better than canopy traps. Hardwood-blend and ethanol performed almost equally in attracting ambrosia beetles in Italy, whereas hardwood-blend and softwood-blend were more attractive to broadleaf-associated species and conifer-associated species, respectively, in Canada. In general, we showed that trapping variables suitable for generic surveillance of longhorn and jewel beetles may also be exploited for survey of bark and ambrosia beetles, but trapping protocols must be adjusted depending on the forest type.

Light Traps in Shipping Containers: A New Tool for the Early Detection of Insect Alien Species.

Insects are one of the most successful groups of invasive species, and the number of new introductions has been increasing in the last decades. Insect invasions are affected mainly by the increase in international trade, as most of them travel across the world inside shipping containers. The effectiveness of sticky light traps was tested for the interception of alien pests inside the containers. The tested hypotheses were that light traps have a valuable broad-spectrum attraction and their trapping performance differs between empty or loaded containers. The optimal trap density in a container was also investigated. Trapping tests were conducted on four model species: Cadra cautella Walker (Lepidoptera: Pyralidae), Drosophila melanogaster Meigen (Diptera: Drosophilidae), Sitophilus zeamais, Motschulsky and Ips typographus L. (Coleoptera: Curculionidae). Insects were released within a standard shipping container, in either empty or loaded conditions, where sticky light traps were deployed for 15 h. Traps were tested with light on (activated) or off (control). Activated traps captured more Lepidoptera and Diptera than control ones, with no differences between empty and loaded container. Instead, Coleoptera were rarely caught, probably because of their ability to escape from traps. Results show that higher trap density in the container (from 1 to 8) increases the probability of insect capture. In conclusion, positive results on C. cautella and D. melanogaster suggest a possible application of sticky light traps against some small Lepidoptera and Diptera species flying in containers and infesting seeds, grains, and fruits, while traps need improvement for application against beetles.