“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.

Evaluation of corn-soybean inter-cropping systems in southwestern Japan

To assess the effects of inter-cropping corn and soybean under southwestern Japan’s climatic conditions, 5 different treatments were compared, namely: CW (mono-cropped corn - weeded); CTW (corn + soybean cv. Tachinagaha - weeded); CT (corn + soybean cv. Tachinagaha - unweeded); CSW (corn + soybean cv. Suzukaren - weeded); and CS (corn + soybean cv. Suzukaren - unweeded). Parameters measured were height, yield, nutrient composition of corn and soybean and the numbers of Japanese beetles (Popillia japonica). Plant height of mono-cropped corn was significantly (P<0.05) greater than that of corn in most of the inter-cropped treatments. The number of Japanese beetles had increased dramatically, especially on unweeded inter-cropped treatments, at 55 DAS (days after sowing). Fresh and dry matter yields (FMY and DMY) of corn did not differ among treatments (P>0.05), while CTW treatment produced higher FMY and DMY for soybean (P<0.05) than in CSW and CS. Weeding tended to reduce the number of Japanese beetles on soybean plants, but it did not affect yield of soybean in this study. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) concentrations in corn cobs, whole corn plants and whole soybean plants did not differ among treatments (P>0.05), while crude protein (CP) concentration in whole corn plants in CTW exceeded (P<0.05) those for mono-cropped corn and CSW treatments. These results indicated that soybean can be successfully inter-cropped with corn in southwestern Japan. Soybean plants may be infested with Japanese beetles. It is advisable to control weeds in the stands to reduce the level of beetle infestation and to minimize competition for the planted crops.

Modelling diapause termination and phenology of the Japanese beetle, Popillia japonica

We developed a mechanistic, stage-structured model simulating the phenology of Popillia japonica. The model simulates the influence of soil temperature on the larval diapause termination and on the development rate function of post-overwintering larvae and pupae. Model parameters are estimated based on literature evidence for pupae development and on a parameterisation process that allows estimating parameters for larval diapause termination and for the development rate function (and the related uncertainty) of post-overwintering larvae. Data used for model parameterisation and validation refer to time-series adult trap catches collected during the P. japonica monitoring programme performed by the Phytosanitary Service of Lombardy Region within the infested area in Lombardy (Italy) from 2015 to 2019. A total of 12 randomly selected locations are used to estimate biologically realistic model parameters (parameterisation dataset). We applied a Jackknife nonparametric resampling procedure on the parameterisation dataset to quantify uncertainty associated with parameters’ estimates. Parameterised model is then validated on time-series adult trap catches data referring to a different set of 12 randomly selected locations (validation dataset) surveyed in Lombardy. The model successfully predicted the beginning of adult emergence and the overall curve of adult emergence in the validation dataset. The model presented can support the definition of the best timing for the implementation of monitoring and control activities for the local and the area-wide management of P. japonica.

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.