Loke T. Kok

• Virginia Tech

This paper presents an overview of rearing activities for Laricobius nigrinus, a predator of the invasive hemlock woolly adelgid and work on other Laricobius spp. at Virginia Tech.

Laricobius nigrinus, a little known Derodontid beetle, is consistently found associated with hemlock woolly adelgid (HWA) in western hemlock seed orchards in British Columbia (Humble 1994). It turns out that Laricobius spp. are prey-specific predators of Adelgidae (Zilahi-Balogh 2004). In collaboration with Forestry Canada, we began studying the po...

To determine if key attributes for a successful biological control agent are possessed by the predator, Laricobius nigrinus Fender, field studies were conducted in its native range of Seattle, WA. The relationship between adult and immature L. nigrinus abundance to different densities of its prey, Adelges tsugae Annand, were determined. In a second...

Biological control of Adelges tsugae (Hemiptera: Adelgidae; Hemlock Woolly Adelgid [HWA]) is an essential component of a management plan for this non-native pest of Tsuga spp. native to eastern N. America. The predatory beetle Laricobius osakensis Montgomery and Shiyake (Coleoptera: Derodontidae) shows potential as a biological control agent becaus...

The sublethal effects of the entomopathogenic fungi, Beauveria bassiana (Balsamo) Vuillemin (strain GHA) and Metarhizium brunneum Petch (strain F-52), on larval weight gain, adult longevity, oviposition, pupation, and eclosion success were investigated in the southern masked chafer, Cyclocephala lurida Bland. Neither M. brunneum nor B. bassiana had...

In 2003, Laricobius nigrinus Fender was introduced into the eastern United States as a biological control agent of the hemlock woolly adelgid (Adelges tsugae Annand). Following its release, it was discovered that L. nigrinus was hybridising and producing viable progeny with Laricobius rubidus LeConte, a species native to eastern North America. Rece...

Ailanthus altissima (Mill.) Swingle commonly known as tree-of-heaven is an invasive tree species that has spread through much of the USA. Significant mortality of A. altissima by a highly host-specific strain of the fungus, Verticillium nonalfalfae Inderb. (formerly Verticillium albo-atrum Reinke and Bethold), has been recently documented in Pennsy...

Daily distributions of eclosion and mating activities of Pseudopidorus fasciata Walker (Lepidoptera: Zygaenidae) were recorded under natural and various laboratory conditions. Eclosion of this insect exhibited circadian gating in constant darkness (DD) but not in constant light (LL) at 28º C. Under natural conditions, the majority of adults emerged...

Laricobius osakensis (Coleoptera: Derodontidae) was imported from Japan to the United States in 2006 for study in quarantine facilities as a potential biological control of Hemlock Woolly Adelgid. Laricobius osakensis was released from quarantine in 2010, but it was soon discovered that the colony also contained a cryptic species, Laricobius nagano...

Eastern hemlocks (Tsuga canadensis Carrière) at two sites in southwestern Virginia were treated by trunk and soil injections of imidacloprid to determine the insecticide's impact on hemlock woolly adelgid, Adelges tsugae Annand. Treatments were 25, 50, and 100% of the highest labeled dosage rates for both stem and soil injection. Three and 4 yr aft...

Bathyplectes anurus and B. curculionis (Hymenoptera: Ichneumonidae) are specialist parasitoids introduced to the United States for classical biological control of alfalfa weevil, Hypera postica (Coleoptera: Curculionidae). Both species of Bathyplectes are established throughout much of the United States, including in Virginia, and often coexist wit...

The hemlock woolly adelgid (HWA) is a non-native insect introduced into the eastern U.S. from Japan. It severely impacts eastern hemlock (Tsuga canadensis L. Carrière) and Carolina hemlock (Tsuga caroliniana Engelman) by their feeding on young branches and twigs, usually at the base where the needles attach. Establishment of biological control pred...

The introduction of hemlock woolly adelgid, Adelges tsugae, into eastern forests has led to major losses of hemlock species, Tsuga spp., indigenous to the region. The primary tool available for managing hemlock woolly adelgid in forest settings is the use of biological control agents. Laricobius rubidus, a known predator of the pine bark adelgid, P...

The parasitic mite Varroa destructor has been a major pest of the European honey bee, Apis mellifera, in the US since its introduction in 1987. The synthetic acaricides currently used for control of V. destructor have many drawbacks, including the development of resistance in the mite and the accumulation of harmful residues in hive materials. A pr...

The hemlock woolly adelgid (HWA), Adelges tsugae Annand, is a serious, non-native pest of hemlock in the eastern North America. Scymnus (Pullus) coniferarum Crotch (Coleoptera: Coccinellidae) is a small lady beetle that preys on HWA in the western U.S. and is absent from hemlock stands in the eastern U.S. While preliminary studies have shown its re...

Eucryptorrhynchus brandti (Harold) and E. chinensis (Oliver) are herbivores of Ailanthus altissima (Mill.) Swingle (tree of heaven) in China. Eucryptorrhynchus brandti has been recommended as a potential biological control agent of A. altissima in North America. In China, the majority of adults of both species were found on tree trunks 0–5 m above...

Ailanthus altissima (Mill.) Swingle, commonly known as tree-of-heaven, is an invasive tree species that has spread throughout the United States since its introduction in 1784 (2). During a survey in July 2009, approximately 1,100 A. altissima trees were observed at two locations in western Virginia (a roadside in Montgomery Co. and a wooded area ad...

The hemlock woolly adelgid, Adelges tsugae Annand, is a serious, non-native pest of hemlock in eastern North America. Laricobius osakensis Montgomery and Shiyake was identified as a key predator in Japan, where A. tsugae is native. Performance of adult and immature stages of L. osakensis was evaluated in sleeve cages on adelgid infested Tsuga canad...

Laricobius osakensis Montgomery & Shiyake, native to Japan, is being measured as a potential biological control agent of the hemlock woolly adelgid, Adelges tsugae Annand, in the eastern United States. Adelges tsugae, a destructive pest threatening the hemlock ecosystems in the eastern United States, was introduced from Japan. This is the first det...

Tree-of-heaven is an invasive, nonnative species that invades newly disturbed areas and forms large monospecific stands. It was surveyed from a vehicle along 5,175 km of roads in Virginia in 2004, 2005, 2010, and 2011. Fifty-eight percent of every 1.6-km road segment had at least one tree-of-heaven. Mean density of tree-of-heaven throughout the roa...

Varroa destructor is an important pest of Apis mellifera, the European honey bee. The mite feeds on both brood and adult bees reducing their immune system and vectoring several damaging viruses. Current methods of mite sampling and control do not consider the spatiotemporal distribution of the mite, and this has, in part, led to the indiscriminate...

The release of biological control agent Laricobius nigrinus for hemlock woolly adelgid, Adelges tsugae, in the eastern United States has had an unintended consequence on a native congener, Laricobius rubidus. Laricobius nigrinus and L. rubidus have been shown to hybridize and complete development on A. tsugae. Laricobius rubidus is a predator of a...

Post‐release distributions of Laricobius nigrinus , a biological control predator of hemlock woolly adelgid Adelges tsugae Annand, were evaluated at eight hemlock forests in the eastern U.S.A. Vertical dispersal of F 1 and F 2 L. nigrinus were assessed from within three crown strata (<7, 7–15 and >15 m) at four release sites. Horizontal distributio...

Two potential biological control agents for the invasive tree-of-heaven, Ailanthus altissima (Mill.) Swingle, have been extensively studied: a vascular wilt fungus, Verticillium nonalfalfae Inderb. et al. (formerly Verticillium albo-atrum Reinke and Berthold), and a host-specific weevil from China, Eucryptorrhynchus brandti Harold, which is current...

Predation, egg production, and survivorship of Laricobius nigrinus Fender, L. rubidus LeConte, and L. osakensis Montgomery and Shiyaki, predators of hemlock woolly adelgid, Adelges tsugae Annand, were investigated in the laboratory and in the field. In individual assays in the laboratory, L. rubidus oviposited fewer eggs than either L. nigrinus or...

Laboratory studies were carried out to determine the functional and numerical responses of the adults and larvae of Laricobius osakensis Montgomery and Shiyake and Laricobius nigrinus Fender to different densities of its prey, Adelges tsugae Annand. Males, females and larvae of both species showed a type II functional response. Overall attack rates...

Ailanthus altissima (Mill.) Swingle, tree-of-heaven, is an invasive species native to Asia. It first was introduced into the United States in the 1700 s and now is distributed throughout much of North America. Mechanical and chemical controls are current suppression tactics, however, implementation is costly. A weevil, Eucryptorrhynchus brandti (Ha...

Coleopteran species are biological control agents of numerous invasive pests. Laricobius nigrinus (Coleoptera: Derodontidae), a predaceous, univoltine species, spends the summer aestivating but is active for the rest of the year. Laricobius nigrinus possesses many essential attributes for effective biological control of the hemlock woolly adelgid (...

Laricobius osakensis Montgomery and Shiyake (Coleoptera: Derodontidae), first identified in Japan in 2005, was evaluated in the field for the biological control of hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae). Long-term (2 months) and short-term (15 days) cage studies were conducted to evaluate survival, reproduction a...

Masked chafer grubs, Cyclocephala spp., are the most widespread and destructive turf pests in VA. Although conventional insecticides are still the main approach for white grub control, their impact on the environment, natural enemies, and the problem of insecticide resistance, have increased public awareness for a more bio-rational approach to mana...

The hemlock woolly adelgid (HWA, Adelges tsugae) is an invasive insect from Japan that has caused extensive mortality of eastern and Carolina hemlock (Tsuga canadensis, T. caroliniana). Releases of Laricobius nigrinus, a predator of HWA native to the PNW and Canada, began in the eastern U.S. in 2003. As of this time, L. nigrinus has been released i...

Very little is known about the searching behavior and sensory cues that Laricobius spp. (Coleoptera: Derodontidae) predators use to locate suitable habitats and prey, which limits our ability to collect and monitor them for classical biological control of adelgids (Hemiptera: Adelgidae). The aim of this study was to examine the visual ability and t...

Eucryptorrhynchus brandti (Harold) (Coleoptera: Curculionidae) was identified in China and studied in quarantine in the United States as a potential biological control agent for the invasive weed, tree of heaven, Ailanthus altissima (Mill.) Swingle (Sapindales: Simaroubaceae). Studies on its general biology and development, and the most efficacious...

Molecular diagnostics based on DNA barcodes can be powerful identification tools in the absence of distinctive morphological characters for distinguishing between closely related species. A specific example is distinguishing the endemic species Laricobius rubidus from Laricobius nigrinus, a biological control agent of hemlock woolly adelgid introdu...

Hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), is an invasive pest of eastern hemlock (Tsuga canadensis (L.) Carrière) and Carolina hemlock (T. caroliniana Englem.) in eastern United States. Host-range tests for Laricobius osakensis Montgomery and Shiyake (Coleoptera: Derodontidae), imported from Japan, were conducted under q...

The intentional use of insects to control weeds has been in practice for more than 150 years. Historically, species from the orders Lepidoptera and Coleoptera have shown the greatest success. Among the Coleoptera, the weevils (family Curculionidae) have played an integral role in the suppression of more than 50% of targeted weed programmes in vario...

Laricobius nigrinus Fender is a specialist predator of the hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae), a lethal pest of hemlock (Tsuga spp.) in the eastern United States. A release was con- ducted in 2003 in Virginia to evaluate survival and oviposition of L. nigrinus adults, egg development in the field, and their i...

Leitneria floridana, corkwood, an uncommon tree native to the southeastern and south central United States, may be threatened by the invasive tree-of-heaven, Ailanthus altissima. Field studies were conducted to assess the morphology and site characteristics of L. floridana throughout its native range and to determine if Ailanthus altissima has inva...

Ailanthus altissima (Mill.) Swingle, tree-of-heaven, is a species native to China and North Vietnam. It was first introduced into the United States in the 1700s and is now distributed and invasive throughout much of North America where it out-competes native vegetation. The invasiveness of tree-of-heaven is primarily attributed to the lack of natur...

Dave Wood became famous in the field of chemical ecology of bark beetles. But over time he branched out into very different research areas. I (SMS) bring this up not because I was famous early in my career, but because my area of research changed as well over time, from working with beetles attacking conifers to focusing on biological control of no...

Eastern hemlock, Tsuga canadensis (L.) Carrière, branchlets were systemically treated with imidacloprid and bioassayed with hemlock woolly adelgid, Adelges tsugae (Annand) (Hemiptera: Adelgidae), and predators. After 10 d, two hemlock woolly adelgid predators, Laricobius nigrinus Fender (Coleoptera: Derodontidae) and Sasajiscymnus tsugae Sasaji & M...

The hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), native to western North America and Asia, was accidentally introduced from Japan to the eastern United States. To potentially establish biological control of A. tsugae, we released a predator endemic to western North America, Laricobius nigrinus Fender (Coleoptera: Derodontid...

The effect of temperature on the duration of egg, larval, prepupal, and pupal development of the predator Laricobius nigrinus Fender was studied at six constant temperatures (6, 9, 12, 15, 18, and 21°C) where Adelges tsugae Annand was used as prey. Developmental time was inversely proportional to temperature between 6 and 18°C. Laricobius nigrinus...

Competitive interactions among two specialist predators, Laricobius nigrinus Fender and Sasajiscymnus (Pseudoscymnus) tsugae Sasaji and McClure, and a generalist predator, Harmonia axyridis Pallas, of hemlock woolly adelgid, Adelges tsugae Annand, were studied in the laboratory. The two specialist predators are part of a biological control program...

The biology and temperature-dependent development of Laricobius kangdingensis Zilahi-Balogh and Jelínek (Coleoptera: Derodontidae), a newly described predator of hemlock woolly adelgid (HWA), Adelges tsugae Annand (Hemiptera: Adelgidae) were investigated and compared with a related HWA predator, L. nigrinus Fender, that has already been released. A...

Imidacloprid is the primary insecticide used against the exotic invasive insect hemlock woolly adelgid, Adelges tsugae Annand, a pest of eastern hemlock [Tsuga canadensis (L.) Carrière] trees in the eastern United States. A competitive enzyme-linked immunosorbent assay (ELISA) was evaluated for quantification of imidacloprid in eastern hemlock wood...

Synchrony and impact of the predators Laricobius nigrinus Fender and Laricobius rubidus LeConte, on hemlock woolly adelgid, Adelges tsugae Annand, were studied in an eastern hemlock field insectary in Virginia. First, a field insectary for propagation of the introduced L. nigrinus was established by planting hemlocks in 2001, infesting them with he...

Weaver ants (Oecophylla spp.) are often found on plants with insect symbionts (trophobionts), but the extent of such associations is not known. Examination of literature records of weaver ant host plants from 1900 to 2006 revealed that Oecophylla smaragdina, native to Asia, was recorded on 175 plant species in 46 families, with 28 associated tropho...

In Malaysia, cultivation of trees in the family Meliaccae, which include valuable tropical timber species such as Swietenia spp. (mahogany) and Khaya spp. (African mahogany), have been severely curtailed by attacks of the mahogan,N shoot borer (Hypsipyla robusta, Lepidoptera: Pyralidac). Mahogany shoot borers pose an international dilemma. Acknowle...

The behavior and daily activity patterns of two specialist predators, Laricobius nigrinus Fender (Coleoptera: Derodontidae) and Sasajiscymnus tsugae, Sasaji and McClure (Coleoptera: Coccinellidae), and a generalist predator, Harmonia axyridis Pallas (Coleoptera: Coccinellidae), of hemlock woolly adelgid, Adelges tsugae (Hemiptera: Adelgidae), were...

Laricobius nigrinus Fender is being reared for release as a biological control agent for hemlock woolly adelgid (HWA), Adelges tsugae Annand. HWA is an introduced insect lethal to hemlock trees (Tsuga canadensis (L.) Carr. and T. caroliniana Engelm.) in the eastern United States. In nature, the predator (Laricobius nigrinus) and its prey (HWA) unde...

Tetraphleps galchanoides Ghauri (Hemiptera: Anthocoridae) nymphs were collected from hemlock woolly adelgid (HWA) Adelges tsugae Annand (Hemiptera: Adelgidae) infested Tsuga sp. in Baoxing, Sichuan, China. First and second stage nymphs collected from foliage shipped from China; were reared to adults and tested for feeding rates and host preferences...

Laricobius baoxingensis Zilahi-Balogh and Jelinek, n. sp., and Laricobius kangdingensis Zilani-Balogh and Jelinek, n. sp., are described from Sichuan Province, China, and the Himalayas. They are compared with other species of the genus from China and a key is provided for the southeastern Palaearctic species. Both species are associated with adelgi...

Fecundity and feeding of two introduced sibling biological control species, Galerucella calmariensis and G. pusilla (Coleoptera: Chrysomelidae) on purple loosestrife, Lythrum salicaria L. (Lythraceae) were compared at constant temperatures of 12.5, 15, 20, 25, and 27.5°C. Larval feeding was also carried out at 30°C, but at this temperature, larvae...

Laricobius nigrinus Fender, native to western North America, was first released in 2003 for the biological control of the hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae), in the eastern United States. Members of the genus Laricobius are known to feed on adelgids, but there is a lack of detailed taxonomic and ecological informat...

1 Competitive interactions among two specialist predators, Laricobius nigrinus and Sasajiscymnus (Pseudoscymnus) tsugae, and a generalist predator, Harmonia axyridis Pallas, of hemlock woolly adelgid, Adelges tsugae were evaluated in hemlock stands in south-western Virginia. The two specialist predators are part of a biological control program for...

Résumé: Zusammenfassung Host specificity studies on Ceuthorhynchidius horridus (Panzer), a weevil which attacks thistles at the rosette stage, revealed that the larvae of this insect were able to complete development in musk thistle ( Carduus nutans L.), plumeless thistle ( Carduus acanthoides L.) and bull thistle ( Cirsium vulgare (Savi) Ten.); bu...

predation, and this occurred at high levels independent of HWA density. Effects of competition among predators were analyzed by a series of tests comparing single predators alone to groups of three conspecifics or heterospecifics. Survival, feeding and reproduction were measured over a 6- day period with moderate HWA densities available throughout....

Laricobius rubidus LeConte, native to eastern North America whose primary host is Pineus strobi Hartig, has been observed in association with Adelges tsugae, an exotic and lethal pest of hemlock trees in eastern North America. Pineus strobi and A. tsugae were used to evaluate host preference and suitability of this predatory beetle to determine in...

Laricobius nigrinus Fender (Coleoptera: Derodontidae) is being evaluated as a biological control agent for the hemlock woolly adelgid (HWA), Adelges tsugae Annand (Homoptera: Adelgidae). Predator exclusion studies on survival, reproduction, and impact on HWA populations were investigated over two years in Virginia, US. In year 1, branches were sele...

Hemlock woolly adelgid (HWA), Adelges tsugae Annand, is an introduced pest of two native hemlock species, eastern hemlock (Tsuga canadensis (L.) Carr.), and Carolina hemlock (T. caroliniana). Currently, chemical control is the most effective way to control HWA infestations in accessible stands and on individual trees. Some of the most widely used p...

Two sympatric Europeanbeetles, Galerucella calmariensis (L.)and G. pusilla (Duft.) (Coleoptera:Chrysomelidae), have been released in NorthAmerica for biological control of purpleloosestrife, Lythrum salicaria L.(Lythraceae). Because establishment isaffected by environmental conditions, studieswere conducted at temperatures ranging from12.5 to 30 C...

Biological studies on Laricobius nigrinus Fender (Coleoptera: Derodontidae) were conducted in the laboratory to obtain basic information on this littleknown predator. Laricobius nigrinus is acandidate biological control agent of thehemlock woolly adelgid, Adelges tsugaeAnnand (Homoptera: Adelgidae), an exotic peston eastern (Tsuga canadensis (L.)Ca...

A gall fly, Urophora affinis Frfld. (Diptera: Tephritidae), released at two sites in southwestern Virginia in 1986 for the biological control of spotted knapweed, Centaurea maculosa Lam., was monitored annually through 2000 to determine its population density and dispersal rate. Between 1986 and 1991, the mean number of U. affinis per knapweed capi...

Laricobius nigrinus Fender, native to the Pacific Northwest, is being evaluated as a potential biological control agent of the hemlock woolly adelgid, Adelges tsugae Annand, in the eastern United States. Members of the genus Laricobius feed exclusively on adelgids. Adelges tsugae is found on hemlocks (Tsuga sp.) in North America and Asia, but is co...

Hylobius transversovittatus Goeze (Coleoptera: Curculionidae), an exotic root feeding weevil, has been released in the USA and Canada for biological control of purple loosestrife Lythrum salicaria L. (Lythraceae), an aggressive emergent aquatic weed of Eurasian origin that has replaced native wetland vegetation. Questions have remained about the es...

Host specificity tests of Laricobius nigrinus Fender (Coleoptera: Derodontidae) were conducted under quarantine in Blacksburg, Virginia, to determine the suitability of this beetle as a biological control agent of the hemlock woolly adelgid, Adelges tsugae Annand (Homoptera: Adelgidae), in the eastern United States. Members of the genus Laricobius...

Like many other Carduus species, slenderflower thistle, Carduus tenuiflorus Curtis, is associated with pastures, disturbed areas, and vacant lots. Invasion is favored by annual burning of pastures. The thistle protects forage from grazing and is a competitive weed in improved pastures.

Bull thistle, Cirsium vulgare (Savi) Tenore, is an invasive thistle from Eurasia, found throughout the United States and in Canada from Newfoundland to British Columbia. It is capable of invading fields, pastures, wastelands and along roadsides, but will not survive in cultivated fields.

Plumeless thistle, Carduus acanthoides L., is an introduced Eurasian noxious weed in pastures, rangelands, croplands, and along highways in 19 of the contiguous states in the United States (Frick, 1978). Carduus acanthoides and Carduus nutans L. in the northeastern United States often occupy the same habitats, such as overgrazed pastures and distur...

Musk thistle, Carduus nutans L., is an invasive weed that has become widespread in the contiguous states of the United States. It is a highly competitive weed of Eurasian origin that has replaced much of the native vegetation in pastures and disturbed areas.

Suppression of the hemlock woolly adelgid (HWA), Adelges tsugae Annand (Homoptera: Adelgidae), in the Eastern United States has focussed on several predators as biological control agents. Three have been released and large numbers of each species will be needed for additional releases. Current rearing programs of predators of the HWA in the laborat...

Laricobius nigrinus (Coleoptera: Derodontidae) shows promise as a useful biological control agent for hemlock woolly adelgid, Adelges tsugae (Homoptera: Adelgidae). A field evaluation was conducted to assess the survival and reproduction of L. nigrinus under natural conditions and to quantify their impact on HWA populations. A predator exclusion st...

The larval endoparasitoid Cotesia orobenae Forbes (Hymenoptera: Braconidae) is an effective natural enemy of the cross-striped cabbageworm, Evergestis rimosalis (Guene) (Lepidoptera: Pyralidae), in southwest Virginia. Routine use of insecticides to control Plutella xyostella (L.) and other lepidopterous larvae in commercial plantings of cabbage, ca...

An epidemiological study was performed on caries, fluorosis and plaque in children of refugees 8, 9 and 10 years of age. Tooth brushing habits and dental attendance were evaluated with a questionnaire. Of the 87 children participating (response rate 89%), 85% showed caries experience, 17% fluorosis and 46% clearly visible plaque. Only 14% of the ch...

Nodding (musk) thistle (Carduus thoermeri Weinmann in the Carduus nutans L. group) and plumeless thistle (Carduus acanthoides L.) are introduced noxious weeds of Eurasian origin. Both weeds are problematic in pastures, rangelands, and croplands and along state highways in many parts of the United States. The success of both species of thistles is l...

Laboratory studies were conducted to evaluate harlequin bug, Murgantia histrionica (Hahn), development on broccoli, mustard, and rape, and feeding damage on broccoli. Duration of the first stadium was 4.9±0.6 days. Development times of the second through fifth instars reared on broccoli, mustard, and rape were not significantly different. However,...

Temperature and host density effects on the development of Cotesia orobenae Forbes (Hymenoptera: Braconidae), and its parasitism of the cross-striped cabbageworm, Evergestis rimosalis (Guenée) (Lepidoptera: Pyralidae), were investigated. Time for adult parasitoid emergence from cocoon masses of C. orobenae maintained at 15, 20, 25, 30 and 35°C and...

Recent research emphasis in the biological control of invasive weeds in Virginia focused on the following weeds: Carduus thoermeri (=nutans) (musk thistle), Carduus acanthoides (plumeless thistle), Cirsium arvense (Canada thistle), Centaurea maculosa (spotted knapweed), and Lythrum salicaria (purple loosestrife). Besides being effective in the cont...

A buckwheat border was planted perpendicular to cucumber and squash rows to attract natural enemies of cucumber beetles. Sticky and modi"ed Malaise traps were used to assess insect populations at incremental distances from the border. The density of Diptera declined from 19.5 insects/sticky card in the border to 2.8 insects/sticky card at 20 m from...

Oviposition, egg development, and adult longevity of Hylobius transversovittatus Goeze (Coleoptera: Curculionidae), a biological control agent of purple loosestrife (Lythrum salicaria L.), were studied at several temperatures. Adults reared at constant temperatures of 12.5, 15, 20, 25, and 30 ± 1°C showed large differences in longevity and oviposit...

This study was initiated to determine the impact of hyperparasitism onCotesia glomerata(L.) (Hymenoptera: Braconidae), an established gregarious endoparasitoid ofPieris rapae(L.) (Lepidoptera: Pieridae).C. glomeratapupae were sampled in field crops of cabbage and broccoli to determine rates of hyperparasitization for each hyperparasitoid species. T...

Broccoli (Brassica oleracea ‘Packman Hybrid’), mustard (B. kabar ‘Southern Giant Curled’), and rape (B. napus ‘Dwarf Essex’) were evaluated as trap crops to manage harlequin bugs,Murgantia histrionica (Hahn), in broccoli field plots during 1994 and 1995 in Montgomery County, Virginia. Mustard and rape prevented low densities of harlequin bugs from...