Phyllobius Oblongus Research Articles

Salix transect of Europe: records of willow-associated weevils (Coleoptera: Curculionoidea) from Greece to Arctic Norway, with insights from DNA barcoding.

BackgroundCurculionid beetles associated with willow (Salix spp.) were surveyed at 42 sites across Europe, from Greece (lat. 38.8 °N) to arctic Norway (lat. 69.7 °N). DNA sequence data provide additional verification of identifications and geographic clustering.New informationIn all, 73 curculionid species were collected from willows, of which seven were particularly abundant. The most widespread species were: Acalyptus carpini Fabricius, 1793 at 15 sites; Tachyerges stigma Germar, 1821 at 13 sites; Phyllobius oblongus (Linnaeus, 1758) at 11 sites; Phyllobius maculicornis Germar, 1824 at 10 sites; and Archarius salicivorus (Paykull, 1792), Melanapion minimum (Herbst, 1797), and Phyllobius cf. pyri (Linnaeus, 1758) all at nine sites. The mean number of curculionid species collected on willow at each site was 5.5 (range 0-14). Compared to chrysomelids, curculionids were richer in species but the species had relatively low average abundance. Widespread curculionid species appear to have scattered and patchy observed distributions with limited geographical structuring in our data. However, deeper sampling (e.g. over multiple seasons and years), would give a better indication of distribution, and may increase apparent geographical structuring. There is some site-to-site variation in colour in a few taxa, but little notable size variation. DNA barcoding, performed on some of the more common species, provides clear species clusters and definitive separation of the taxonomically more challenging species, as well as some interesting geographic insights. Our northernmost sample of Phyllobius oblongus is unique in clustering with Canadian samples of this species. On the other hand, our samples of Acalyptus carpini cluster with European samples and are distinct from a separate Canadian cluster of this species. We provide the first available DNA sequences for Phyllobius thalassinus Gyllenhal, 1834 (Hungary).

Efficacy of agrochemicals against Phyllobius oblongus

The contact, residual, and ingestion efficacy of two conventional insecticides was compared with that of another five environmentally friendly agrochemicals in a laboratory for the control of the European snout beetle. Very good efficacy was observed for the conventional product Reldan 22<sup>®</sup> after all types of exposures. The conventional Mospilan<sup>®</sup> 20 SP showed good efficacy after ingestion. SpinTor<sup>®</sup> was very effective 72 h after ingestion and contact, and Siltac<sup>®</sup> EC showed comparable efficacy with conventional insecticides 72 h after ingestion and residual contact. SpinTor<sup>®</sup> and Siltac<sup>®</sup> conform to the principles of organic farming and integrated pest management (IPM) and are able to replace both the tested conventional products in young fruit plantations and nurseries. Pyrethrum PNC – 17, FerrumOil, and Boundary SW did not sufficiently control the beetle.

Predilection of Chaitophorus populeti and Phyllobius oblongus on four clones of white poplar

The predilection of Poplar shoot aphid (Chaitophorus populeti Panzer) and European Snout Beetle (Phyllobius oblongus L.) in the first and second growing season in two experimental plantations. Four white poplar clones were tested: Villafranca, L-100, L-80, and L-12. The first experimental plot was established at the beginning of 2019 and the second in 2020 near Novi Sad (northern Serbia). Predilection of C. populeti Panzer was performed on three plants per each of three blocks and every of four clones. Predilection of P. oblongus L. was evaluated on all leaves of five shoots on three plants per each of three blocks of every of four clones. According to the results of analysis of variance and Tukey's test for several traits describing intensity of damage and percentage of damaged leaves, there was significant difference between examined clones in prevalence of P. oblongus L. Significantly stronger attack was found for clones L-80 and L-12 than on Villafranca and L-100 in both years on plants in their first growing period. The damage from this pest in second growing period could almost not to be detected. In case of C. populeti Panzer, the prevalence was assessed according to the percentage of colonized shoots. The differences between examined clones were significant only in first growing period in 2019, where the strongest attack was found on clones Villafranca and L-100, and the weakest on clones L-80 and L-12. Results of the study are particularly important in the context of clones L-12 and L-80 performances evaluation, considering that these clones are still in the experimental phase of testing. Likewise, the intensity of attacks of studied pest species suggests that special attention to their presence and spreading should be paid in the first growing season after plantation establishment.

Landscapes, orchards, pesticides–Abundance of beetles (Coleoptera) in apple orchards along pesticide toxicity and landscape complexity gradients

Abstract Landscape composition may influence biodiversity and ecosystem services in agricultural fields. Hitherto, most studies have focused on annual crops and the available information on the impacts of landscape structure in orchards is sparse. In this study, we evaluated the effects of pesticide use as cumulative toxicity on pest and predatory beetle (Coleoptera) assemblages in the canopy of apple orchards surrounded by different proportion of semi-natural vegetation, crop fields and settlements in Hungary. Laboratory data suggest that increasing pesticide toxicity negatively affects predators (coccinellids), but we did not find such a pattern. Supposedly, the effect of pesticides was masked by the continuous recolonisation of orchards from the surrounding landscape. On the contrary, for the less mobile pest species [Anthonomus pomorum, Phyllobius oblongus (Curculionidae)] we did find a decline in abundance along the gradient of increasing pesticide toxicity. Landscape composition around the orchards significantly influenced the abundance of predatory, fungivorous and tourist species, but had no effect on pests. Contrary to expectations, however, semi-natural habitats had a minor effect compared to arable fields, orchards and settlements which habitat types had various effects on the abundance of different coleopteran groups and species. For example, Harmonia axyridis (Coccinellidae) abundance was positively affected by its overwintering sites, i.e. human settlements in spring, semi-natural forests in summer, and arable fields in autumn. The mass immigration of other predatory, fungivorous and tourist species from the surrounding arable fields into the orchards started from July with senescence and harvesting of arable crops. These results suggest that arable fields, other orchards and settlements might be more important sources of colonisation for natural enemies in orchards than certain semi-natural habitats.

Variable host phenology does not pose a barrier to invasive weevils in a northern hardwood forest

1 A suite of invasive weevils has established in hardwood forests of the North American Great Lakes Region. We quantified patterns of host availability and the capacity of adults to succeed in a system with high host variability both within and between seasons in Michigan, U.S.A. 2 We quantified phenological development of foliage on three host species [sugar maple, Acer saccharum Marshall; ironwood, Ostrya virginiana (Mill.) K. Koch; and raspberry, Rubus spp.]. We estimated adult abundance using emergence traps and sweep net sampling over 3 years, and compared field host associations with laboratory choice assays. 3 Host plant phenology varied among species, between years, and in their interactions. The four most common weevils, Phyllobius oblongus (L.), Polydrusus sericeus (Schaller), Barypeithes pellucidus (Boheman) and Sciaphilus asperatus (Bonsdorff), emerged in early to mid-June, in approximately that order. After emergence, each species showed evidence of host preference based on their abundances on foliage. Overall, P. oblongus and B. pellucidus were most prevalent on sugar maple, P. sericeus was most prevalent on ironwood, and S. asperatus was relatively evenly distributed. Laboratory choice tests with P. oblongus and P. sericeus confirmed these preferences. 4 These four invasive species comprised over 99% of all 12 845 weevils obtained, suggesting displacement of native species. The optimal sampling methods varied among weevil species. 5 These invasive weevils contend with the highly variable conditions of their environment, and also potential phenological asynchrony, via relatively late emergence, even at the cost of lower host quality. Annual variation is greater for numbers of adults than larvae, suggesting that mortality of late instars or pupae is particularly important.

Temporal and Species Variation in Cold Hardiness Among Invasive Rhizophagous Weevils (Coleoptera: Curculionidae) in a Northern Hardwood Forest

Abstract A complex of invasive rhizophagous weevils has established in North American northern hardwood forests. Little is known regarding the overwintering biology of these weevils and thus how cold hardiness and weather affect population dynamics. Field data from winter 2006–2007 showed a decline in larval abundance but an increase in larval weight of the surviving individuals. During winter 2008–2009, we examined several aspects of overwintering biology of Phyllobius oblongus (L.), Polydrusus sericeus (Schaller), and Barypeithes pellucidus (Boheman). Larvae were collected in the Upper Peninsula of Michigan and transported in bulk field soil to the University of Notre Dame, South Bend, IN, for laboratory assays. Supercooling points (SCPs) of P. oblongus and B. pellucidus larvae not in contact with ice were highest in October and lowest in March, but SCPs of larvae that were in contact with ice did not differ among sampling dates. Larval cold tolerance increased over the winter, with 11% of P. oblongus and 40% of P. sericeus surviving 24 h at -12°C. Few B. pellucidus or P. oblongus survived 30 d at temperatures of -3.3°C or lower. Body water content increased from January to March in P. sericeus and B. pellucidus. Larval hemolymph from all species showed some thermal hysteresis and hexagonal crystal formation, indicative of low levels of antifreeze proteins or glycolipids. These subterranean-dwelling larvae are buffered from ambient winter temperatures, but our data also suggest low levels of freeze avoidance. We discuss how these overwintering strategies may affect adult population dynamics.

Host Plant Phenology Affects Performance of an Invasive Weevil,Phyllobius oblongus(Coleoptera: Curculionidae), in a Northern Hardwood Forest

We investigated how host plant phenology and plant species affected longevity, reproduction, and feeding behavior of an invasive weevil. Phyllobius oblongus L. (Coleoptera: Curculionidae) is common in northern hardwood forests of the Great Lakes Region. Adults emerge in spring, feed on foliage of woody understory plants, and oviposit in the soil. Preliminary data indicate that adults often feed on sugar maple, Acer saccharum Marshall, foliage early in the season, then feed on other species such as raspberry, Rubus spp. Whether this behavior reflects temporal changes in the quality of A. saccharum tissue or merely subsequent availability of later-season plants is unknown. We tested adult P. oblongus in laboratory assays using young (newly flushed) sugar maple foliage, old (2-3 wk postflush) sugar maple foliage, and raspberry foliage. Raspberry has indeterminate growth, thus always has young foliage available for herbivores. Survival, oviposition, and leaf consumption were recorded. In performance assays under no-choice conditions, mated pairs were provided one type of host foliage for the duration of their lives. In behavioral choice tests, all three host plants were provided simultaneously and leaf area consumption was compared. Adults survived longer on and consumed greater amounts of young maple and raspberry foliage than old maple foliage. P. oblongus preferred young maple foliage to old maple foliage early in the season, however, later in the growing season weevils showed less pronounced feeding preferences. These results suggest how leaf phenology, plant species composition, and feeding plasticity in host utilization may interact to affect P. oblongus population dynamics.

Effects of habitat amount and isolation on biodiversity in fragmented traditional orchards

Summary1. Habitat fragmentation is a major threat to biodiversity and can lead to the loss of both species and ecosystem services, but fragmentation effects vary greatly between studies and studied organisms. Understanding the distinct effects of habitat amount and isolation at the patch and landscape scale may account for some of this variation.2. We studied biodiversity in 30 traditional orchards that were selected for independent variation in habitat amount and habitat isolation at the patch and landscape scale. We analysed species richness and abundance of snails, beetles, true bugs, spiders and breeding birds that avoid open farmland but occur in woody vegetation types. Additionally, the abundances of nine single species were analysed using specific habitat definitions.3. Surprisingly, the effects of habitat isolation were more important than the effects of habitat amount. Effects at the patch scale were more frequent than landscape‐scale effects.4. Spider species richness decreased with increasing patch‐scale habitat amount. Abundance of the weevilPhyllobius oblongusincreased with landscape‐scale habitat amount. Negative effects of patch isolation were greater for predatory birds and spiders, while the predominately herbivorous beetles, true bugs and snails were less affected. Species richness of birds, spiders and beetles, and abundance of birds,Cyanistes caeruleus,Parus majorandFringilla coelebs, decreased with increasing patch‐scale habitat isolation. In contrast, species richness of spiders and beetles increased with increasing landscape‐scale habitat isolation.5. Synthesis and applications. The effects of habitat fragmentation differed between taxonomic groups, with stronger and more consistent responses in birds than invertebrates. Our understanding of fragmentation effects may be biased due to the dominance of bird studies in the literature, and further invertebrate studies are encouraged. Landscape management to improve biodiversity or ecosystem services requires a group‐specific approach and coordinated priority setting. High habitat connectivity benefited wood‐preferring birds, spiders and beetles, lending support to national initiatives for increased habitat connectedness. The negative effects of patch isolation were greater for natural pest regulators, birds and spiders than for herbivorous beetles and bugs.

Laboratory Performance of Two Polyphagous Invasive Weevils on the Predominant Woody Plant Species of a Northern Hardwood Community

A complex of invasive weevils that consume roots as larvae and foliage as adults have become established in northern hardwood forests in North America. We evaluated adults of the two most prominent species, Phyllobius oblongus and Polydrusus sericeus, for longevity, foliage consumption, and egg production on several putative hosts commonly found in this ecosystem. Adult pairs were monitored in no-choice laboratory assays for the duration of their lifespans on basswood, Tilia americana, ironwood, Ostrya virginiana, sugar maple, Acer saccharum, raspberry, Rubus spp., or leatherwood, Dirca palustris. Overall, P. sericeus lived more than twice as long as P. oblongus and lived longer on all hosts. P. sericeus consumed more total leaf area than P. oblongus on basswood, ironwood, and raspberry, but P. oblongus had a higher leaf consumption rate on sugar maple. Basswood was a very good host for P. sericeus. Leatherwood was not a suitable host for either weevil species. The higher longevity and fecundity of P. sericeus than P. oblongus did not agree with that expected from population data, in that the latter species is substantially more abundant. This likely reflects P. oblongus ' superior performance on sugar maple, the dominant flora in the study area. These data provide a basis for estimating the broader impacts of adult weevil feeding.

Kaolin particle films suppress many apple pests, disrupt natural enemies and promote woolly apple aphid

AbstractMultiple applications of hydrophobic kaolin particle film in apple orchards suppressed numbers of blossom weevil (Anthonomus pomorum), brown leaf weevil (Phyllobius oblongus), attelabid weevil (Caenorhinus pauxillus), leafhoppers (Empoasca vitis and Zygina flammigera) and green apple aphid (Aphis pomi) colonies. The kaolin treatments reduced the apple sawfly (Hoplocampa testudinea) fruit infestation on cultivar J. Grieve, and the fruit damage caused by oyster scale (Quadraspidiotus ostreaeformis), mussel scale (Lepidosaphes ulmi), early caterpillars, leaf rolling moths (Tortricidae), fruitlet‐mining tortrix moth (Pammene rhediella) and codling moth (Cydia pomonella). There was no effect on the number of colonies of rosy leaf curling aphid (Dysaphis devecta), nor on the fruit damage caused by common earwig (Forficula auricularia) and apple sawfly on cv. G. Delicious. The level of infestation of rosy apple aphid (Dysaphis plantaginea), leaf miner moths (Phyllonorycter blancardella, Lyonetia clerkella), and agromyzid flies (Phytomyza heringiana) increased in the kaolin‐treated plots. Kaolin treatments promoted woolly apple aphid (Eriosoma lanigerum) infestation, which became severe, while it reduced the abundance of polyphagous predators like F. auricularia, predaceous Heteroptera and Coleoptera, the red velvet mite (Allothrombium fuliginosum), spiders (Araneae) and the abundance of common black ant (Lasius niger). The treatments also reduced parasitism of the apple sawfly by the ichneumonid Lathrolestes ensator. Many weeks after ending the kaolin treatments, the number of predaceous Coleoptera and especially the number of spiders remained low in the kaolin‐treated plots.

Composition and Seasonal Phenology of a Nonindigenous Root-Feeding Weevil (Coleoptera: Curculionidae) Complex in Northern Hardwood Forests in the Great Lakes Region

Phyllobius oblongus (L.), Polydrusus sericeus (Schaller), and Sciaphilus asperatus (Bonsdorff) comprise a complex of nonindigenous root-feeding weevils in northern hardwood forests of the Great Lakes region. Little is known about their detailed biology, seasonality, relative abundance, and distribution patterns. We studied 10 sites over a 2-yr period. Two sites were in northeastern Wisconsin, and eight were in the neighboring southern upper peninsula of Michigan. Larval abundance was estimated by soil sampling, and adult abundance was estimated by sweep netting, emergence trapping, and beating samples. Sweep netting collected the most weevils overall (71.0%), whereas beating and emergence traps collected 22.1 and 6.9%, respectively. P. sericeus were the predominant larvae, representing 34.3% of total Curculionidae, whereas P. oblongus were the predominant adults, representing 66.4% of Curculionidae. Few S. asperatus and Trachyphloeus aristatus (Gyllenhal) larvae and adults were collected, with the latter being a new record for Wisconsin. Two additional species, Barypeithes pellucidus (Boheman) and an undetermined Polydrusus sp., were collected only as larvae. Six species of curculionids were collected overall, with at least five being confirmed as nonindigenous species. P. oblongus and P. sericeus adults were the most abundant. These did not coincide temporally. Over 63% of P. oblongus and P. sericeus were collected during single 4-wk intervals in mid-June and mid-July, respectively. Conversely, S. asperatus adults overlapped with both other species, occurring sparingly from 4 June through 28 August. One species was predominant at each site and generally accounted for ≥80% of the total weevil population. P. oblongus larvae and adults predominated in five and eight sites, respectively, whereas P. sericeus and S. asperatus larvae and adults predominated in one site each. Adult and larval populations were generally clustered. We evaluated vertical stratification of P. sericeus larvae in the soil, and most were located within the top 10 cm.

New Records of Native and Introduced Weevils (Coleoptera: Curculionidae) for Nova Scotia from Cape Breton Island

Abstract Eleven species of weevils native to North America, Acalyptus carpini (Herbst), Tachyerges ephippiatus (Say), Bagous transversus LeConte, Ceutorhynchus omissus Fall, Ceutorhynchus squamatus LeConte, Auleutes nebulosus (LeConte), Perigaster liturata (Dietz), Stethobaris ovata (LeConte), Carphonotus testaceus Casey, Rhyncolus brunneus Mannerheim and Pissodes fiskei Hopkins, and seven species introduced to North America, Sitophilus oryzae (Linnaeus), Sitophilus granarius (Linnaeus), Gymnetron pascuorum (Gyllenhal), Gymnetron tetrum (Fabricius), Tychius meliloti Stephens, Phyllobius oblongus (Linnaeus), and Polydrusus sericeus (Schaller) are reported for the first time in Nova Scotia based on specimens from Cape Breton Island. New records for native species reflect increased collecting and attention to the fauna of Nova Scotia. Historically, many introduced insects first established populations in North America in the Canadian Maritimes and in fact about 40% of the species listed in the most recent ch...

Host Breadth and Ovipositional Behavior of AdultPolydrusus sericeusandPhyllobius oblongus(Coleoptera: Curculionidae), Nonindigenous Inhabitants of Northern Hardwood Forests

Polydrusus sericeus (Schaller) and Phyllobius oblongus (L.) are nonindigenous root-feeding weevils in northern hardwood forests of Wisconsin and Michigan. Detailed studies of adult host range, tree species preferences, and effects of food source on fecundity and longevity have not been conducted in North America. P. sericeus and P. oblongus adults fed on leaves of all 11 deciduous tree species offered in no-choice assays, but amount of consumption varied among species. P. sericeus consumed more yellow birch (Betula alleghaniensis Britton), basswood (Tilia americana L.), and ironwood [Ostrya virginiana (Miller) K. Koch] than maple (Acer spp.). Conversely, P. oblongus consumed more ironwood than poplar (Populus spp.) and yellow birch, with maple being intermediate. Females ate 2.5 times as much as males. Mean frass production by P. sericeus was strongly correlated with foliage consumption among host tree species. In feeding choice assays, P. sericeus preferred yellow birch over ironwood, basswood, and aspen (Populus tremuloides Michaux). P. sericeus produced 29.93 ± 1.43 eggs/d when feeding on yellow birch compared with 2.04 ± 0.36 eggs/d on sugar maple (Acer saccharum Marshall). P. oblongus produced 4.32 ± 1.45 eggs/d when feeding on sugar maple compared with just 0.2 ± 0.1 eggs/d on yellow birch. Overall, total egg production for P. sericeus and P. oblongus averaged 830.1 ± 154.8 and 23.8 ± 11.8 eggs, respectively, when feeding on their optimal host plants. P. sericeus survived approximately five times longer in assays than P. oblongus, and it oviposited a total of 25.8 ± 4.0 d, whereas P. oblongus oviposited 1.9 ± 0.9 d. Egg size among P. sericeus and P. oblongus was 0.53 ± 0.008 by 0.32 ± 0.003 and 0.56 ± 0.005 by 0.29 ± 0.004 mm, respectively. In laboratory rearing of P. sericeus on yellow birch seedlings, 18% of the initial 500 larvae completed development to adults.

Phyllobius oblongus and Sciaphillus asperatus Associated with Sugar Maple Reproduction in Northern Michigan 123

The bionomics of 2 weevils, Phyllobius oblongus (L.) and Sciaphillus asperatus Bonsdorff (Coleoptera: Curculionidae) were studied in Michigan during 1972–74. P. oblongus adults were present from late May to about July 20. Adult abundance peaked during the 3rd week of June. Adults fed on 22 plant species, but primarily defoliated sugar and mountain maple, American elm, yellow birch, and black cherry. They laid eggs a few cm into the soil. The mean hatch was 24.2 days. The larvae fed on young rootlets of sugar maple and other host trees. Five larval instars occurred from late June until late fall. The insect overwintered as a mature larva and pupation occurred in early spring. The mean duration of the pupal stage was 17.7 days. Most twig scarring, resulting in terminal die-back and forking on small sugar maple trees, was caused by S. asperatus adults. Sugar maple was the primary host of S. asperatus . Dense adult populations were found in all study areas from late April until late September. Surveys of 6600 sugar maple terminal buds showed an average of 0.28 terminal buds per 100 stems per year damaged by weevil-like bud feeding. No conclusive causal agent was determined, but S. asperatus was the most probable suspect.

DEFORMITY OF SUGAR MAPLE CAUSED BY BUD FEEDING INSECTS

AbstractInjury to sugar maple buds, shoots, twigs, and stems resulted in forked trees in Upper Michigan. Six species of insects were observed to feed on buds: The lepidopterans Proteoteras moffatiana Fernald (Olethreutidae), Obrussa ochrefasciella (Chambers) (Nepticulidae), Choristoneura rosaceana (Harris) and Cenopis pettitana (Robinson) (Tortricidae), and the coleopterans Phyllobius oblongus (L.) (Curculionidae) and Platycerus virescens (F.) (Lucanidae). Twig and shoot damage resulted from severed shoots, twig cankers, and scarring resembling weevil feeding injury. Stem damage was caused by breakage and browsing animals. Bud injury averaged 5.80% per year, twig damage 3.18% per year, and stem breakage 0.36% per year. Injuries to terminals resulted in 85% forked stems, 8% single stems, 3% stunting, and 4% unaffected.