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Species Richness and Seasonal Abundance of Billbugs, Sphenophorus spp., from South Carolina Golf Courses 1
Abstract
Species richness and seasonal abundance of billbugs (Coleoptera: Curculionidae) were determined for four golf courses in South Carolina. In 2009 and 2010, 3970 adult billbugs representing six species were collected with unbaited pitfall traps. Sphenophorus inaequalis (Say) and S. venatus vestitus Chittenden represented 95% of the billbugs collected, whereas S. coesifrons Gyllenhal, S. parvulus Gyllenhal, S. cariosus (Olivier), and S. minimus Hart composed the remainder of the billbugs captured. Adult billbugs were collected from March to December, with a sex ratio of roughly 1:1. More individuals of S. venatus vestitus and S. inaequalis were collected from March to July and August to November, suggesting two overlapping generations annually. Given the extended activity period, at least two insecticide applications may be needed to reduce the abundance of larvae and adults.
... However, billbug species composition varies regionally, resulting in a nationwide collage of billbug species assemblages (Johnson-Cicalese 1990, Dupuy and Ramirez 2016). In recent decades, regional variation in adult species composition and seasonal phenology has been documented in Arkansas (Young 2002), Florida (Huang andBuss 2009, Huang andBuss 2013), New Jersey (Johnson-Cicalese et al. 1990), North Carolina (Doskocil and Brandenburg 2012), South Carolina (Chong 2015), Virginia (Kuhn et al. 2013), and Mexico (Ordaz-González et al 2014). However, despite high damage potential, larval populations are more difficult to characterize. ...
... Johnson-Cicalese et al. (1990) observed nearly equal abundances of these four species in cool-season turfgrasses in New Jersey, whereas in the present study, S. venatus dominated warm-season turfgrasses and S. parvulus was most abundant in cool-season Kentucky bluegrass. Such dissimilarities in billbug species composition and abundances between trapping sites within a region has also been documented in South Carolina (Chong 2015), North Carolina (Doskocil and Brandenburg 2012), and Florida (Huang and Buss 2013), and may be related to the host species present, variation in management regimes, or a combination of these factors. ...
... This is the first study investigating hunting billbug S. venatus seasonal biology in the Midwest. As in the present study, malebiased trap captures for S. venatus across the growing season has been reported in New Jersey (Johnson-Cicalese et al. 1990), Florida (Huang and Buss 2013), and South Carolina (Chong 2015). The apparently male-biased sex ratio observed in the present study (67-69% male) was most similar to findings of Johnson-Cicalese et al. (1990) in New Jersey, where 65% of the S. venatus adult population were male. ...
Eleven species of billbugs (Coleoptera: Dryophthoridae: Sphenophorus spp. Schönherr) infest managed turfgrass in North America. However, the regional variation in species composition remains unresolved and the seasonal phenology of several species has not been well documented. The latter gap is largely due to the inability to identify the larval stage to species-a confounding problem with several sympatric insect species. We used field trapping (adults) and soil sampling (larvae and pupae) surveys along with a DNA-based life-stage association to characterize the biology of billbugs associated with turfgrass in the Midwestern United States. Pitfall trapping at four locations in Indiana revealed four billbug species: S. venatus Say, S. parvulus Gyllenhaal, S. minimus Hart, and S. inaequalis Say. Sphenophorus venatus was the most abundant species on warm-season turfgrass while S. parvulus was most abundant on cool-season turfgrass. Investigation of S. venatus seasonal biology revealed two overwintered life stages-larva and adult-which resulted in two overlapping cohorts and two larval generations. Degree-day models describing S. venatus activity were more accurate for first-generation adults and larvae than for overwintering life stages. Maximum-likelihood analyses provided the first molecular species identification of billbug larvae and direct evidence that S. venatus larvae are capable of overwintering above 40°N latitude. Findings clarify the utility of molecular markers (CO1, 18S, and ITS2) for describing billbug larval population dynamics and seasonal phenology in regions where several sympatric billbug species occur. These results support the development of sustainable management strategies based on billbug seasonal phenology in different regions of North America.
... Carolina (Chong 2015), and North Carolina Brandenburg 2012, Reynolds et al. 2015). However, it has also been documented further north into Virginia (Kuhn et al. 2013) and (Vittum et al. 1999) and Japan (Yoshia and Nabeshima 1981). ...
... Chemical intervention is often the only viable option to manage billbug pests in turfgrass and three basic strategies, targeting different life stages, have been most widely adopted (Richmond 2016, Shetlar andAndon 2012): 1) preventative control of adults using contact insecticides when adult activity is initiated in the spring 2) preventive control of early instar larvae inside the stems using systemically active insecticides and 3) curative application of soil insecticides targeting larger larvae in the soil after damage is visible. To reduce reliance on chemical insecticides and improve management, billbug research in recent decades has focused on understanding regional variation in species composition (Chong 2015, Huang and Buss 2009) and seasonal activity Brandenburg 2012, Young 2002), improving insecticide application timing (Reynolds and Brandenburg 2015), and developing effective cultural management strategies (Huang and Buss 2013, Fry and Cloyd 2011, Reinert et al. 2011, Richmond et al. 2000. Billbug chemically-mediated behavior and the potential for incorporating semiochemicals into billbug monitoring and management programs has not been previously studied. ...
... observed nearly equal abundances of these four species in cool-season turfgrasses in New Jersey, while in the present study, S. venatus dominated warm-season turfgrasses and S. parvulus was most abundant in cool-season Kentucky bluegrass. Dissimilarities in billbug species compositions and abundances between trapping sites has also been documented in South Carolina(Chong 2015), North Carolina(Doskocil & Brandenburg 2012), and Florida(Huang & Buss 2009) and may be related to the host species present, variation in management regimes, or a combination of these factors.Three of the four species, S. parvulus, S. minimus, and S. inaequalis, all produced one generation a year, and had significant overlap in peak adult activity from May-June.In contrast, S. venatus adults initiated activity earlier in the spring (March) and displayed multiple peaks of adult activity throughout the growing season. Important differences in the seasonal activity of S. venatus relative to the three additional sympatric billbug species documented during this study could complicate management in regions where these phenologically divergent species are present. ...
... 1a and 1b); while from the roots with lesions caused by insects and from the soil the rhizophagous insects were collected with the aid of entomological pins ( fig. 1c) and of a small metallic shovel, according to the recommendation made by Juang-Horng (2015). ...
A study was conducted in order to determine the main species of rhizophagous insects associated to the turfgrass varieties in the Varadero Golf Club (Matanzas, Cuba). During 2010-2015 root samples from the turf of varieties Bermuda grass 328 and tifdwarf (hybrids obtained from Cynodon dactylon (L.) Pers x Cynodon transvaalensis Burtt-Davy) were evaluated, which were extracted through a hole-cutting device. In them the main associated rhizophagous insects were collected and the lesions were identified and described. Thirteen insect species were found, corresponding to five orders and eight families, which were found in all the game areas (except in the rough); the taxa with higher incidence belonged to the orders Hemiptera and Coleoptera. Due to the affectations they caused on the turf of both hybrids the burrower bugs Dallasiellus varaderensis Marrero and Mayorga, Tominotus inconspicuus Froeschner and the true weevils Sphenophorus sp. (1) and Sphenophorus sp. (2) stood out; proving their potential as pest insects of the turf in Cuba for the grasses of the Cynodon genus, because the root affectations caused chlorosis, burns and localized death of the turfgrass in the Varadero Golf Club. As a result of the inventory conducted the recording, for the first time, of the two species of the Sphenophorus genus stands out. It is recommended to identify the Sphenophorus species and to include them, along with D. varaderensis and T. inconspicuus, in the available list of the insect species associated to turfgrasses in the country.
Billbugs (Sphenophorus spp.) are a complex of grass-feeding weevil species that reduce the aesthetic and functional qualities of turfgrass. Effective billbug monitoring and management programs rely on a clear understanding of their seasonal biology. However, our limited understanding of regional variation in the species compositions and seasonal biology of billbugs, stemming primarily from our inability to identify the damaging larval stage to species level, has hindered efforts to articulate efficient IPM strategies to growers. We used a combination of DNA barcoding methods and morphometric measures to begin filling critical gaps in our understanding of the seasonal biology of the billbug species complex across a broad geographic range. First, we developed a DNA barcoding reference library using cytochrome oxidase subunit 1 (COI) sequences from morphologically identified adult billbugs collected across Indiana, Missouri, Utah and Arizona. Next, we used our reference library for comparison and identification of unknown larval specimens collected across the growing season in Utah and Indiana. Finally, we combined our DNA barcoding approach with larval head capsule diameter, a proxy for developmental instar, to develop larval phenology charts. Adult COI sequences varied among billbug species, but variation was not influenced by geography, indicating that this locus alone was useful for resolving larval species identity. Overlaid with head capsule diameter data from specimens collected across the growing season, a better visualization of billbug species composition and seasonal biology emerged. This approach will provide researchers with the tools necessary to fill critical gaps in our understanding of billbug biology and facilitate the development of turfgrass pest management programs.
The billbug, Sphenophorus spp. (Coleoptera: Curculionidae), is an important pest complex in sod farms in Georgia. Larval feeding within stolons and on roots affects spring recovery of slow-growing zoysiagrass and poses a serious challenge to machine harvesting, as the damaged turfgrass rarely holds together. Little is known about major billbug species and their seasonal occurrence and abundance in Georgia sod farms, as most previous research was conducted in golf courses in the region. In 2018 and 2019, adult billbugs were sampled from five zoysiagrass sod field sites in central Georgia. Four linear pitfall traps were used per site from February to December each year, and the traps were checked at weekly intervals. The data show that >98% of the sampled billbugs were the hunting billbug, Sphenophorus venatus vestitus Chittenden, whereas the nutgrass billbug, Sphenophorus cariosus Olivier; uneven billbug, Sphenophorus inaequalis Say; and vegetable weevil, Listroderes difficilis Germain were the minor species. Seasonal billbug capture was influenced by turfgrass phenology (e.g., early-growth-stage, late-growth-stage or fully grown turfgrass). The numbers of Sphenophorus spp. collected were significantly greater in the fully grown turfgrass than in the early- or late-growth-stage turfgrasses. Significantly greater densities of billbug were found in Zoysia matrella (L.) Merrill ('Zeon') and the Z. matrella × Zoysia pacifica (Goudswaard) M. Hotta & S. Kuroki hybrid ('Emerald') than in the Zoysia japonica (Steudel) cultivars 'El Toro' and 'Zenith'. Similar numbers of male and female billbugs were collected from the sod field sites.
A study was conducted in order to determine the main species of rhizophagous insects associated to the turfgrass varieties in the Varadero Golf Club (Matanzas, Cuba). During 2010-2015 root samples from the turf of varieties Bermuda grass 328 and tifdwarf (hybrids obtained from Cynodon dactylon (L.) Pers x Cynodon transvaalensis Burtt-Davy) were evaluated, which were extracted through a hole-cutting device. In them the main associated rhizophagous insects were collected and the lesions were identified and described. Thirteen insect species were found, corresponding to five orders and eight families, which were found in all the game areas (except in the rough); the taxa with higher incidence belonged to the orders Hemiptera and Coleoptera. Due to the affectations they caused on the turf of both hybrids the burrower bugs Dallasiellus varaderensis Marrero and Mayorga, Tominotus inconspicuus Froeschner and the true weevils Sphenophorus sp. (1) and Sphenophorus sp. (2) stood out; proving their potential as pest insects of the turf in Cuba for the grasses of the Cynodon genus, because the root affectations caused chlorosis, burns and localized death of the turfgrass in the Varadero Golf Club. As a result of the inventory conducted the recording, for the first time, of the two species of the Sphenophorus genus stands out. It is recommended to identify the Sphenophorus species and to include them, along with D. varaderensis and T. inconspicuus, in the available list of the insect species associated to turfgrasses in the country.
Billbugs (Coleoptera: Curculionidae: Sphenophorus spp.) are a complex of weevil pests affecting turfgrass throughout the United States. Billbug larvae cause damage by feeding in stems, on roots, and on the crowns of turf, causing severe discoloration and eventual plant death. Monitoring efforts have focused on nondestructive pitfall sampling of ground-active billbug adults and on destructive sampling using soil cores for larval stages in the soil. Given the cryptic nature of the susceptible larval stages, billbugs are typically managed by preventive applications of long-residual, systemic insecticides, including neonicotinoids and anthranilic diamides. Despite knowledge of effective management practices including pest-resistant turf varieties, irrigation management, and microbial controls that contribute to an IPM approach, billbug management continues to rely heavily on prophylactic synthetic insecticides. This review will summarize the identification and biology of billbugs and strategies for their management.
In the southeastern United States, hunting billbug, Sphenophorus venatus vestitus Chittenden, adults are often observed in turfgrass, but our knowledge of their biology and ecology is limited. Field surveys and experiments were conducted to determine the species composition, life cycle, damaging life stage, and distribution of billbugs within the soil profile in turfgrass in North Carolina. Linear pitfall trapping revealed six species of billbug, with the hunting billbug making up 99.7% of all beetles collected. Data collected from turf plus soil sampling suggest that hunting billbugs have two overlapping generations per year in North Carolina and that they overwinter as both adults and larvae. Field experiments provided evidence that adult hunting billbugs are capable of damaging warm season turfgrasses.
Billbugs (Coleoptera: Curculionidae: Sphenophorus spp.) are common pests whose damage is often misdiagnosed on turfgrass in the United States. Consequently, Florida turfgrass managers have been struggling to satisfactorily control billbug outbreaks. Thus, we sought to determine the species complex, abundance, seasonality, and fecundity of key Sphenophorus spp. from field collections, and quantify duration of developmental and daily activity periods through greenhouse rearing tests. From January 2006 to December 2007, > 18,000 adults of 10 different Sphenophorus spp. were collected from four linear pitfall traps on each of two golf courses in north central and two courses in southern Florida. Sphenophorus venatus vestitus Chittenden was the most abundant species, making up > 94% of all specimens collected from three of the four golf courses (80.9% of all specimens collected). Adults were active and mature eggs were present in female ovaries nearly every week of the year. Adults were nocturnal. S. v. vestitus development from egg to adult can occur in 8-9 wk on 'Tifway' bermudagrass [Cynodon dactylon (L.) Pers.] or 'Empire' zoysiagrass (Zoysia japonica Steud.), with up to six overlapping generations per year, depending on environmental conditions. Thus, any time of year could be suitable to target either adults or larvae, and a repeated application may be needed to manage subsequently emerged larvae or eclosed adults.
Zoysiagrass, in general, has few insect pest problems but may suffer significant damage from infestations of the bluegrass billbug (Sphenophorus parvulus Gyllenhal). This study evaluated 'Meyer' and DALZ 0102 zoysiagrass (both Zoysia japonica Steud.) and 31 experimental zoysiagrass progeny, including reciprocal crosses between Z. japonica × Z. matrella (L.) Merr. or crosses between 'Emerald' (Z. japonica × Z. pacifica Goudsw.) × Z. japonica. These grasses were evaluated in adjacent experiments with 18 progeny in one and 13 in another. Plots were maintained under golf course fairway conditions and experienced natural infestations of the bluegrass billbug in 2009 and 2010 with larval damage primarily evident in June and continuing throughout the remainder of the growing season. 'Meyer' suffered the highest level of damage on each of six rating dates, ranging from 17% to 38% of the experimental plot area affected. Among the zoysiagrass progeny, damage ranged from 0% to 35% with most showing less than 15% damage. Overall, zoysiagrass progeny associated with reciprocal crosses of Z. japonica × Z. matrella or 'Emerald' x Z. japonica were less susceptible to bluegrass billbug than 'Meyer'.
Abundance and population dynamics of adult Sphenophorus inaequalis were monitored at 4 bermudagrass golf courses in Florida. Sphenophorus inaequalis was present at 3 of the courses, but was the dominant billbug species at one public golf course in Gainesville, FL. Peak activity occurred from Jun to Aug in both 2006 and 2007 in Gainesville. Sphenophorus inaequalis appears to be univoltine and populations are localized within Florida.
Sphenophorus venatus vestitus responses to 4 bermudagrass cultivars and endophytic perennial ryegrass-overseeded bermudagrass were evaluated in greenhouse tests. 'TifEagle' appeared to be least preferred, compared to 'Tifway', 'Celebration' and 'Tifdwarf '. Pots of 'TifEagle' overseeded with endophytic perennial ryegrass had less adult damage and no larvae, compared to that of 'Tifway.' Using less susceptible cultivars and overseeding with endophytic turfgrasses can minimize billbug populations in warm season turfgrasses.
Hunting billbugs (Sphenophorus venatus vestitus Chittenden) cause damage to zoysiagrass (Zoysia spp.) and bermudagrass (Cynodon spp), which is often misdiagnosed as the effects of drought, disease, or another soil insect. Populations have increased over the past several decades and are causing extensive damage on grasses in lawns, golf courses and other land-scapes. Nine cultivars of Zoysia were evaluated for resistance to S. venatus vestitus in a field cage choice test in a paired cage split-plot experiment. Leaf-firing of plant canopy was considered an above ground expression of root feeding damage by billbug larvae. ‘Diamond’ and ‘Zorro’ exhibited significantly less leaf firing damage (a reduction of 6.1 and 9.8%, respectively). In contrast, ‘Palisades’, ‘Meyer’, and ‘Crowne’ showed >40% canopy damage. When root, shoot, and total plant dry weights were compared, ‘Diamond’, 'Zorro’, ‘Cavalier’, and ‘Royal’ [all Z. matrella (L.) Merr.] sustained less dry weight reduction (<53%) than ‘Palisades’, ‘Meyer’, and ‘El Toro’ (all Z. japonica Steud.) with 76, 74, and 70% total dry weight reductions, respectively. Cultivars of Z. matrella appear to be more resistant as a group than the Z. japonica cultivars.
The seasonal distributions and biology of four species of billbug on New Jersey turfs during 1986 and 1987 were examined; Sphenophorus parvulus Gyllenhal, a common pest of turfgrass, and three additional species, S. venatus s.l. (Say), S. minimus Hart, and S. inaequalis (Say), that had previously been overlooked as pests of cool-season turfgrasses in New Jersey. Linear pitfall trap collections of adults indicated: (1) a nearly equal overall abundance of the four species, (2) greater activity of S. inaequalis in the early spring and autumn, and (3) continued activity of S. venatus through the summer. The abundance of S. venatus adults throughout the summer, and continuous egg laying of all four species through August suggested a partial second generation. Larvae of all four species were found damaging cool-season turfgrasses during July. Laboratory-rearing work found little difference in the number of days for egg hatching and pupation, but a longer larval period for S. venatus. To facilitate identification and study by turfgrass specialists, an illustrated key to eight known billbug turf pests is provided and their geographic distributions in the United States are reviewed.