“What’s This Bug?” Questions from the Public Provide Relevant Information on Species Distribution and Human–Insect Interactions

In general, insects and arthropods polarizing: they either fascinate people, disgust people, or both, and they generate lots of questions. Museums are perceived as reliable sources of information and, as such, a go-to destination for the public to receive answers. Since its opening in 1990, the Montreal Insectarium has offered an entomological information service, allowing the public to send questions, photographs, and specimens for identification. All requests are answered by entomologists. Spatiotemporal variations in taxonomic, geographic, and thematic profiles of the 4163 requests received in 2010–2011 and 2017–2018 were analyzed. Requests came from 35 countries, and most of those requests came from Canada. The majority of requests were identification requests. Representing 25% of identification requests, the five most frequent species were the eastern dobsonfly Corydalus cornutus, the masked hunter Reduvius personatus, the giant water bug Lethocerus americanus, the western conifer-seed bug Leptoglossus occidentalis, and the Japanese beetle Popillia japonica. A comparison with the data from the citizen science platform iNaturalist shows that the EIS can be a valuable tool for invasive species detection. Frequent subjects included school projects, entomophagy (eating insects), and wasp and bee nests. Finally, we discuss the role of entomologists in providing scientific information but also in addressing common concerns regarding cohabitation with arthropods.

Mulches Used in Highbush Blueberry and Entomopathogenic Nematodes Affect Mortality Rates of Third-Instar Popillia japonica

Popillia japonica Newman (Japanese beetle) is an invasive, polyphagous pest in North America, as adults feed on plant foliage and larvae on roots. Management in crops relies on foliar and soil applications of insecticides, but entomopathogenic nematodes (EPN) are effective biocontrol agents. In highbush blueberry, mulches (composts, woodshavings, sawdust, bark) are used for weed control and fertility. Therefore, our objective was to determine the effects of Heterorhabditis bacteriophora and Steinernema scarabaei on third-instar P. japonica in substrates commonly used as mulches in blueberry. In containers in the laboratory, larval mortality was 90–100% with H. bacteriophora for all substrates, but rates with S. scarabaei were lower and variable among substrates. A mixture of municipal compost + woodchips/sawdust resulted in 60% larval mortality without adding EPN, but few nematodes were recovered, indicating other causes of death. In a field microplot experiment in October, larval mortality rates were 50% at most for all EPN and substrate type combinations, likely due to lower than optimal soil and substrate temperatures for EPN survival and infectivity. Overall, a compost and woodchip/sawdust mulch should help suppress P. japonica populations in blueberry, and applying H. bacteriophora when temperatures are optimal to mulches can provide excellent larval control.

Biodiversity in a Cool-Climate Vineyard: A Case Study from Quebec

In Quebec (Canada), viticulture has experienced steady growth in the last 35 years in terms of surfaces cultivated and value, although it is practiced in climatic conditions at the edge of what is considered a cool-climate area. This case study documents biodiversity studies conducted at the l’Orpailleur vineyard (Dunham, QC, Canada) from 1997 to 2021. In a first phase starting in 1997, the biodiversity of insecticide-free and insecticide-treated plots was determined for the taxa Scarabaeidae, Curculionidae, Chrysomelidae, Cicadellidae, Acari and Aranae. This step provided a baseline allowing to identify key arthropods. In a second phase starting in 2004, entomological issues were addressed on an ad hoc basis. In 2014, a third phase began with a perspective of sustainability and management of plant diversity in the vineyard to conserve natural enemies. Because of increased Japanese beetle (Popillia japonica-Scarabaeidae) populations and threats to vineyards, a biocontrol program based on the parasitoid Istocheta aldrichi (Tachinidae) was initiated. The unusually fast development of grapevines during the growing season, selection of flowering species, as well as selected arthropods associated with these flowering species, will be illustrated. Periodic update of protection programs will be required to address future challenges associated with climate change scenarios and world trade.

Management of Popillia japonica in container-grown nursery stock in Italy

The Japanese beetle Popillia japonica is an invasive alien species recently introduced and established in Northern Italy. Adult beetles are very polyphagous and feed on vines, fruit trees, forest trees, crops, vegetables, ornamental and wild plant species. Eggs are usually laid by females in moist grassland in the summer, singly or in small clusters. Larvae feed on roots and may be transported in soil of plants for planting grown in containers. Restrictions on movement of plants grown in containers from infested to non-infested areas imposed by phytosanitary regulations have a significant economic impact on the nursery industry. An innovative approach was used to exclude beetle oviposition by weed mulching available for container-grown nursery stocks, and by testing larval survival to the application of chemical (cypermethrin) and organic (Heterorhabditis bacteriophora and Metarhizium brunneum) commercial pesticides registered for European nurseries. The high effectiveness of the method makes it a suitable component of a systems approach strategy for pest risk management, in order to achieve a safe production and trade of nursery plant material in areas infested by the Japanese beetle.

Results from Hop Cultivar Trials in Mid-Atlantic United States

‘Hop’ (Humulus lupulus) cultivar trials were conducted at sites in three Virginia counties (Northampton, Chesterfield, and Madison) in response to demand by the craft beer industry for local ingredients. In 2016, a replicated study involving five cultivars (Cascade, Chinook, Newport, Nugget, and Zeus) was established on an 18-ft-tall trellis system at each site. Weather data influencing infectivity of downy mildew (Pseudoperonospora humuli) and powdery mildew (Podosphaera macularis), two economically important hop diseases, was collected, and to the extent possible, similar cultural practices were applied at each site. Climatic conditions favorable to P. humuli and P. macularis were present throughout the experimental period, and P. humuli infection was widespread at all sites starting from 2017. Among common pests, Japanese beetle (Popillia japonica) was the only one observed to cause significant damage. Unseasonably high rainfall in 2018 led to crop failure at all but the Northampton site, and harvesting was done at all sites only in 2017 and 2019. Yields (kilograms per hectare by weight) in 2017 were found to be ≥45% lower than second-year estimates for yards in the north and northwestern United States. Quality attributes (α and β acids; essential oil) for cones harvested from the Chesterfield site were comparable to published ranges for ‘Cascade’ in 2019, but lower for the other cultivars. More work is needed to identify or develop cultivars better suited to conditions in the southeastern United States. The influence of terroir on quality of commercial cultivars produced in the region should also be examined.

Popillia japonica (Japanese beetle).

The Japanese beetle was first discovered in New Jersey, USA in 1916. It probably entered the USA as grubs with iris bulbs before 1912 when plant materials were first examined. Although not a pest in Japan, extensive, well-watered, turf, and a lack of parasites, allowed populations to rapidly build up and spread steadily west to the Mississippi River. The loss of the chlorinated hydrocarbon insecticides, and the end of the Federal quarantine on nursery stock, has allowed beetles to move into western states at a rapid rate. Beetles are pests of quarantine concern in the western USA and Europe. P. japonica was found on Terceira Island, Azores, Portugal in the 1980s. Again, extensive turf allowed establishment of beetles, population explosions, the infestation of that island, and subsequently of three more of the Azorean Islands. Beetles have moved considerably outside of the climatic conditions in their native Japan.

Relative Susceptibility, Preference, and Suitability ofCarpinusTaxa for the Japanese Beetle (Coleoptera: Scarabaeidae) 1

Nineteen Carpinus taxa were evaluated in no-choice and multiple-choice laboratory feeding bioassays for susceptibility, preference, and suitability for the adult Japanese beetle (Popillae japonica Newman). No-choice laboratory feeding bioassays revealed that only three Carpinus taxa, Carpinus caucasica Grossh., Carpinus tschonoskii Maxim., and the hybrid Carpinus caroliniana x C. coreana, were significantly less susceptible and less suitable to feeding and for reproduction by Japanese beetles. Leaf tissue removed was related to the amount of frass produced, but was not related to leaf thickness, inner or outer leaf toughness, or fecundity. Frass production did not reflect fecundity. Hybridization may have either a positive or negative effect on host susceptibility, preference, and suitability. When a moderately preferred species such as C. caroliniana Walter or C. betulus L. is crossed with a species of equal or higher susceptibility, (i.e. C. coreana Nakai, Blume, or C. laxiflora (Sieb. and Zucc.) Blume) feeding preference increases. A “C. tschonskii factor” (Maxim.) appears to affect susceptibility and preference. There does not appear to be a large pool of Carpinus taxa suitable for future tree breeding programs in areas where Japanese beetle outbreaks are common. Potential use of Carpinus taxa in urban landscapes and forests is discussed.Index words: Susceptibility, preference, suitability, Japanese beetle, Popillia japonica, Carpinus.Species used in this study: Carpinus betulus L., C. caroliniana Walter, C. caucasica Grossh, C. cordata Blume, C. coreana Nakai, C. fargesii Franch, C. japonica Blume, C. laxiflora, (Sieb. and Zucc.) Blume, C. orientalis Mill, C. tschonoskii Maxim, C. turczaninowii Hance, C. betulus x tschonoskii, C. caroliniana x betulus, C. caroliniana x (C. betulus x tschonoskii), C. caroliniana x cordata, C. caroliniana x coreana, C. caroliniana x orientalis, C. caroliniana x tschonoskii, C. caroliniana x coreana, C. cordata x C. japonica, and, Sassafras albidum (Nutt.) Nees.

Evaluation of Indigenous Entomopathogenic Nematodes as Potential Biocontrol Agents against Popillia japonica (Coleoptera: Scarabaeidae) in Northern Italy

The natural presence of entomopathogenic nematodes (EPNs) has been investigated in the Piedmont region (Northern Italy) in areas infested by the Japanese beetle Popillia japonica. Thirty-nine out of 155 soil samples (25.2%) were positive for EPNs. Most of the samples contained only steinermatids (92.3%), 5.1% contained heterorhabditids, and one sample (2.6%) contained both genera. All the recovered isolates were identified at species level both morphologically and molecularly. Steinernema carpocapsae was the most abundant and it was mainly distributed in open habitats, such as perennial meadows, uncultivated soils, and cropland, characterized by sandy loam soil texture and acidic pH. Steinernema feltiae has been found associated mainly with closed habitats such as coniferous and deciduous woodland, characterized by sandy loam-texture and extremely acidic soil. The three isolates of Heterorhabditis bacteriophora were collected only in open habitats (perennial meadows and uncultivated fields) characterized by strongly acidic soils with sandy loam texture. The virulence of all EPN natural strains was evaluated by laboratory assays against P. japonica third-instar larvae collected during two different periods of the year (spring, autumn). The results showed that larval mortality was higher for pre-wintering larvae than post-wintering ones. The five more promising EPN isolates were tested in the semi-field assay in which H. bacteriophora natural strains have been shown to be more efficient in controlling P. japonica grubs. All of these results are finally discussed considering the use of these natural EPNs as biological control agents against P. japonica, within an eco-friendly perspective of management.

Size and shape assortative mating in Japanese beetles (Popillia japonica)

Assortative mating is hypothesized to be a product of sexual selection, mating constraints, or temporal autocorrelation. I test these hypotheses in the Japanese beetle (Popillia japonica Newman, 1841), a sexually size dimorphic invasive insect pest in North America, by measuring the size and shape of bodies and wings of pair members in a wild population. Because male P. japonica prefer to mate with larger females and larger males outcompete rivals for mating opportunities, sexual selection is expected to produce size-related assortative mating. The current study did not support this hypothesis. The mating constraints hypothesis was also not supported because beetle pairs did not have similar body shapes. I, however, did find support for the temporal autocorrelation hypothesis as the wing size and shape of pair members were significantly correlated. This mating pattern likely arises due to individuals with larger and more slender wings arriving earlier at aggregation sites and pairing according to their arrival sequence. Although I found less support for the sexual selection hypothesis, I argue that mate choice might play an important, but secondary, role to temporal autocorrelation in explaining assortative mating in Japanese beetles.