Host plant, oviposition behavior and larval ecology of a sawfly leafminer, Profenusa japonica (Hymenoptera: Tenthredinidae)

The host plant, oviposition behavior and larval ecology of Profenusa japonica Togashi are reported for the first time. Adults of P. japonica mated and oviposited on a polyantha rose, Rosa multiflora (Rosaceae), in April. Each female adult laid an egg on the edge of a leaflet. Hatched larvae consumed the parenchymatous layer of leaflets and in so doing created a mine. The larval stage comprised five instars. On average, 70.6% of the total area of a leaflet was consumed by one larva. Female adults of P. japonica laid eggs singly, probably to avoid larval competition for food.     

Establishment and spread of two introduced parasitoids (Ichneumonidae) of the birch leafminer, Fenusa pusilla (Lepeletier) (Tenthredinidae)

Lathrolestes nigricollis(Thomson) and Grypocentrus albipes Ruthe,Palearctic specialist parasitoids of thebirch-leafmining sawfly Fenusa pusilla(Lepeletier), were imported from central Europe andreleased at three locations in Edmonton, Alberta,Canada during 1994–1996. Parasitoids becameestablished at two locations, L. nigricollis atboth and G. albipes at one, and were recoveredfor 3–5 years after release. Lathrolestesnigricollis has dispersed throughout most ofEdmonton, and at least 13 km from release sites, butG. albipes has been recovered only 400–500 mfrom one release site. Five years after introductionat one site, percent parasitism by L.nigricollis was 78% and 84% for the first andsecond generations, respectively, and about 48% ofparasitoid eggs were encapsulated.     

Revision of the western Palaearctic Mesoleptus (Hymenoptera: Ichneumonidae)

The western Palaearctic species of the genus Mesoleptus Gravenhorst 1829 are redescribed and keys are given for their identification. Also a key for the identification of the three stilpnine genera (Atractodes, Mesoleptus, and Stilpnus) is given and the biology of the genus is discussed shortly. The following species are described as new: Mesoleptus hispanicus n. sp., M. sawoniewiczi n. sp. and M. tunisiensis n. sp. The male of Mesoleptus tobiasi Jonaitis is described for the first time. New combinations is M. incessor (Haliday). New synonyms number 143 and 34 lectotypes are chosen.     

Efficiency and establishment of three introduced parasitoids of the mealybug Paracoccus marginatus (Hemiptera: Pseudococcidae)

Three introduced parasitoids Acerophagus papayae, Anagyrus loecki, and Pseudleptomastix mexicana of the mealybug Paracoccus marginatus have been released in Miami-Dade and Broward counties (Florida) in 2003. Efficiency and establishment of these previously introduced parasitoids to control P. marginatus were measured in 2005 and 2006, at three locations in Homestead (Miami-Dade). Mealybug populations were initially established on three branches (per plant) of 10 hibiscus plants inside closed-sleeve cages. The three treatments, closed, open, and no-cage environments were applied to the three established mealybug populations on each plant. The number of mealybugs and natural enemies was monitored in all treatments. After 72 h, the number of P. marginatus in the open-sleeve cage was higher than in the no-cage treatment but both were lower than the number in the closed-sleeve cage. Efficiency of parasitoids was evaluated by their percentage parasitism. Percentage parasitism (=recovery) was also used as an indicator for parasitoid establishment. Two of the three previously released parasitoids (A. papayae and A. loecki) were recovered in this study. Acerophagus papayae had a higher percentage parasitism than A. loecki in both the open-sleeve cage (31.0% vs 2.3%) and the no-cage treatments (21.4% vs 1.6%) and caused the most mortality of P. marginatus. There was no recovery of P. mexicana in either of the treatments. Although both A. papayae and A. loecki were established in tested areas, A. papayae was more efficient in controlling P. marginatus than A. loecki. The reasons for not recovering P. mexicana in release areas is yet unknown.     

Biology and host range of the leafminer,Pseudonapomyza sp. (Diptera: Agromyzidae), a potential biological control agent for Tecoma stans (Bignoniaceae) in South Africa

Tecoma stans (Bignoniaceae), is an evergreen shrub that has a wide natural distribution in the tropical and subtropical parts of the western hemisphere. This shrub is native to Mexico and the southern regions of the USA. This weed is widely distributed in South Africa and neighbouring countries. As part of the biological control initiative, a leafmining fly, Pseudonapomyza sp. (Diptera: Agromyzidae), was imported into South Africa, and was subsequently studied as a potential biological control agent for T. stans. During no-choice tests involving 46 plant species in 16 families, Pseudonapomyza sp. only oviposited and developed on T. stans. Neither oviposition nor larval development was recorded on the closely related and indigenous plant species. When six plant species in the Bignoniaceae family were exposed to Pseudonapomyza sp. during multi-choice tests, oviposition and larval development only occurred on T. stans. It was concluded that Pseudonapomyza sp. was sufficiently host-specific to be released against T. stans in South Africa. Pseudonapomyza sp. also displayed very promising biological attributes that could enhance its effectiveness to control T. stans.     

Potential impact of the native hyperparasitoid Conura albifrons (Hymenoptera: Chalcididae) on the exotic biological control agent Diadromus pulchellus (Hymenoptera: Ichneumonidae)

The solitary pupal parasitoid Diadromus pulchellus was released in 2010 as a classical biological control agent against leek moth, Acrolepiopsis assectella, an important new pest of onion crops, Allium spp. in Eastern North America. Post-release monitoring using sentinel leek moth pupae revealed that the facultative hyperparasitoid Conura albifrons was attacking leek moth and potentially D. pulchellus as well. We used laboratory choice and no-choice tests to assess the potential impact of C. albifrons on leek moth and D. pulchellus. C. albifrons is capable of developing in newly formed leek moth pupae and leek moth pupae containing first instar D. pulchellus, as well as in fully developed D. pulchellus pupae. Survivorship of both leek moth and D. pulchellus exposed to C. albifrons was significantly lower than that of unexposed controls. In choice trials, prior host experience significantly influenced host choice by C. albifrons. These results suggest that C. albifrons could impact the establishment of D. pulchellus through both competition and intraguild predation, and that the impact has the potential to change as the relative frequency of the two hosts shifts in field populations.     

An entomopathogenic fungus and nematode prove ineffective for biocontrol of an invasive leaf miner Profenusa thomsoni in Alaska

A non-native invasive sawfly, the amber-marked birch leaf miner Profenusa thomsoni (Konow), was first detected in south-central Alaska in 1996 and is now widely distributed throughout urban and wild birch trees in Alaska. Impacts have been considered primarily aesthetic because leaf miners cause leaves of birch trees (Betula spp.) to senesce prematurely, but the leaf miners likely also reduce birch vigour and thereby increase susceptibility to diseases and other insects. We tested the ability of commercially available biological control agents to control P. thomsoni. The entomopathogenic fungus Beauveria bassiana (Bals.-Criv.) Vuillemin GHA strain and the entomopathogenic nematode Steinernema carpocapsae (Weiser) were applied in aqueous suspension to the soil/litter surface beneath infested birch trees in Alaska at one site in 2007 and 2008 and two sites in 2010. There was no evidence the fungus or nematode controlled P. thomsoni. Instead, there was evidence the fungus increased the density of this pest insect at two sites, likely by reducing its predators. As tested, B. bassiana and S. carpocapsae do not appear effective as biological controls of P. thomsoni.     

A Retrospective Analysis of the Establishment and Dispersal of the Introduced Australian Parasitoids Xanthopimpla rhopaloceros (Krieger) (Hymenoptera: Ichneumonidae) and Trigonospila brevifacies (Hardy) (Diptera: Tachinidae) within New Zealand

Two Australian parasitoids, Xanthopimpla rhopaloceros (Krieger) and Trigonospila brevifacies (Hardy), were introduced to New Zealand to control the light-brown apple moth (Epiphyas postvittana Walker). Dispersal by the parasitoids has since occurred naturally and with the aid of releases in fruit-growing areas. The present geographical range of the parasitoids includes all the North Island and some offshore islands to latitude 41 20 S. X. rhopaloceros is also present to latitude 41 48 S in the South Island. Comparisons of these distributions with those in Australia indicate that climatic conditions may have played a major role in the areas of establishment of both species in New Zealand. The mean winter temperature may be a limiting factor in the dispersal of T. brevifacies and X. rhopaloceros in New Zealand. Other factors that have probably aided the successful dispersal of the parasitoids include the wide distribution of host Tortricidae and the occurrence of tortricid host plants. The areas of New Zealand that appear suitable for further colonization by T. brevifacies include northern areas of the South Island, and both parasitoids could disperse further into suitable climate areas of the east and west coasts of the central South Island. The rate of dispersal for X. rhopaloceros was estimated at 13-24 km/year, and for T. brevifacies at 8-15 km/year.     

Host specificity, establishment and dispersal of the gorse thrips, Sericothrips staphylinus Haliday (Thysanoptera: Thripidae), a biological control agent for gorse, Ulex europaeus L. (Fabaceae), in Australia

Sericothrips staphylinus was released as a biological control agent for Ulex europaeus in New Zealand and Hawaii following tests on ca. 80 plant species which showed it was narrowly oligophagous. To determine the suitability of S. staphylinus for release in Australia, further host specificity tests were conducted on 38 species and cultivars of Australian plants. These tests confirmed that S. staphylinus would feed only on U. europaeus in Australia and, following formal approval, was released in Tasmania during January 2001. To develop an optimal release strategy for S. staphylinus under Australian conditions, a field trial based on an earlier New Zealand study was conducted by replicating releases of 10, 30, 90, 270 and 810 adults. Results showed that population growth, reproduction rate and the number of S. staphylinus recovered 14 months after release can be non-linear functions of release size and establishment could be achieved with as few as 10 thrips. As S. staphylinus is easily cultured ca. 250 thrips were chosen as the minimum number for release because, based on a negative binomial model, this release size produced close to the maximum population growth. Surveys in early 2007 recovered S. staphylinus from 80% of 30 sites in Tasmania, the post release period ranging from 1 to 6 years. However, densities were low (<1 thrips/cm of tip growth) with no evidence of visible plant damage. The maximum dispersal range was 180–250 m after 38 months. At all the other sites, dispersal was estimated at less than 120 m. It is possible that S. staphylinus populations are still in the lag phase of their establishment before starting to increase rapidly and disperse. However, the survey results support a recent Tasmanian study which indicated that S. staphylinus is a sedentary, latent species characterised by steady densities and low levels of damage to its host plant. Its efficacy as a biological control agent on gorse may be restricted primarily by ‘bottom up’ effects of plant quality limiting its rate of natural increase and an inability of the thrips to reach large, damaging populations under field conditions.     

Allantus luctifer (Hymenoptera: Tenthredinidae), a candidate agent for the biological control of Rumex spp.

The dock plant (Rumex spp.) is one of the most problematic pasture weeds worldwide. Allantus luctifer was selected as a potential biological control agent for Rumex spp. Continuous rearing of A. luctifer was carried out from 2005 to 2006, and its general biology is presented in this report. The preliminary host specificity test showed a promising result for using A. luctifer to control Rumex spp.     

Geographic structure with no evidence for host-associated lineages in European populations of Lysiphlebus testaceipes,an introduced biological control agent

Lysiphlebus testaceipes (Cress.) is an aphidiine parasitoid originally introduced to Europe as a biological control agent of citrus aphids in the Mediterranean. It has rapidly become widespread in coastal areas continuing gradually to expand inland. L. testaceipes exploited a large number of aphids in Europe, including new hosts and significantly changed the relative abundance of the native parasitoids. This behavior may reflect a broad oligophagy of the introduced parasitoid or it may require the evolution of host specialization that results in genetically differentiated subpopulations on different hosts. To address this issue we used the mitochondrial cytochrome oxidase subunit I and seven microsatellite loci to analyze the structure of genetic variation for L. testaceipes samples collected from 12 different aphid hosts across seven European countries, as well as some samples from Benin, Costa Rica, USA, Algeria and Libya for comparison. Only five COI haplotypes with moderate divergence were identified overall. There was no evidence for the association of haplotypes with different aphid hosts in the European samples, but there was geographic structuring in this variation. Haplotype diversity was highest in France, where L. testaceipes was introduced, but only a single haplotype was detected in areas of south-eastern Europe that were invaded subsequently. The analysis of microsatellite variation confirmed the lack of host-associated genetic structure, as well as differentiation between populations from south-western and south-eastern Europe. The parasitoid L. testaceipes in Europe is thus an opportunistic oligophagous species with a population structure shaped by the processes of introduction and expansion rather than by host exploitation.     

Pediobius metallicus (Hymenoptera: Eulophidae): First record of a parasitoid wasp of the agromyzid fly Japanagromyza tokunagai,a serious pest of orchids

Agromyzid flies, also known as leafminer flies, are one of the most serious insect pests that infest various plants. An agromyzid fly Japanagromyza tokunagai lays eggs in the ovaries of various Japanese orchids during or shortly after anthesis. Consequently, seed predation by J. tokunagai has the potential to severely limit the reproduction of many endangered orchids in Japan. While agromyzid populations tend to be suppressed by rich communities of natural parasitoids, such parasitoids have yet to be reported. Here we report Pediobius metallicus as the first record of a parasitoid of J. tokunagai. It is highly unusual to find parasitoids infesting J. tokunagai, possibly because the fly is protected by the thick wall and three-dimensional structure of orchid capsule. Pediobius metallicus may play an important role in suppressing J. tokunagai population at least in our study site.     

Comparative analysis of the reproductive biology of two Peristenus species (Hymenoptera: Braconidae), biological control agents of Lygus plant bugs (Hemiptera: Miridae)

Peristenus digoneutis Loan and Peristenus stygicus Loan, parasitoids of the European tarnished plant bug Lygus rugulipennis Poppius, are established in the United States for biological control of native North American Lygus species, and are being considered for deliberate release in Canada. High lifetime fecundity of parasitoids is considered a desirable attribute of biological control agents and therefore, an understanding of parasitoid reproductive biology is required. In the present study, the potential lifetime fecundity of both agents was compared under laboratory conditions to estimate the potential impact of Peristenus species on Lygus. Synovigenic P. digoneutis and P. stygicus females oviposited most actively in the first two weeks of their lifetime, with a maximum average daily oviposition rate after five days. The maximum number of eggs laid per day was 83 eggs for P. stygicus, and 36 eggs for P. digoneutis. P. digoneutis has an average potential lifetime fecundity of 385 ± 35 SE eggs produced over 22 ± 3 SE days. In contrast, P. stygicus females have a 50% higher mean potential lifetime fecundity reaching 782 ± 65 SE eggs over 28 ± 1 SE days. A positive correlation between lifetime fecundity and body size was found only for P. stygicus, and both species showed a significant relationship between lifetime fecundity and oviposition period. The present study demonstrates that the fecundity of P. digoneutis and P. stygicus is considerably higher than previously reported. Based on these findings, P. stygicus appears to be the most effective biological control agent for Lygus lineolaris (Palisot de Beauvois) when only fecundity is taken into consideration.     

Life history of Aptesis nigrocincta (Hymenoptera: Ichneumonidae) a cocoon parasitoid of the apple sawfly, Hoplocampa testudinea (Hymenoptera: Tenthredinidae)

Aptesis nigrocincta: Gravenhorst is a bivoltine ectoparasitoid of apple sawfly cocoons, hosts that must be found and parasitized by females at a depth of 10-25 cm in the soil. Females are significantly smaller than males and nearly wingless. After encountering a host, females needed 29.3 min at 20 degrees C and 19. 9 min at 25 degrees C to deposit an egg on the host. Development from egg to adult took 39.6 days for females and 38.0 days for males at 20 degrees C. This small difference was significant. At 20 degrees C, the longevity of females that had no opportunity to oviposit was on average 72.5 days, significantly higher than male longevity (50.6 days). The longevity of females given access to hosts throughout their lifetime averaged 58.6 days. Females were able to mate immediately after emergence and copulation lasted on average 21.7 s. After a pre-oviposition period averaging 5.8 days, females laid 20.2 eggs during their lifetime, thus less than one egg per day. Neither the fecundity nor longevity of individual females was correlated with body size. If females were deprived of food, longevity as well as lifetime fecundity were drastically reduced. Field studies were carried out in one organically managed apple orchard in Switzerland. Aptesis nigrocincta showed parasitism rates ranging from 12.1 to 39.7 % within single parasitoid generations, thereby constituting the most important mortality factor of apple sawfly cocoons.     

Introduction and establishment of parasitoids for the biological control of the apple ermine moth, Yponomeuta malinellus (Lepidoptera: Yponomeutidae), in the Pacific Northwest

Four parasitoids were imported from five countries in Eurasia and released in northwestern Washington, US, to control the apple ermine moth (AEM), Yponomeuta malinellus Zeller, which colonized the Northwest around 1981. From 1988 to 1991, 95,474 individuals of Ageniaspis fuscicollis (Dalman) from France, China, Korea, and Russia were released in Washington. Parasitism of AEM increased 4- to 5-fold over that produced by preexisting natural enemies between 1989 and 1994 at 22 monitored sites. Subsequently, the wasp dispersed up to 20 km from release sites. A. fuscicollis also parasitized the cherry ermine moth, Yponomeuta padellus (L.), which was discovered in the Pacific Northwest in 1993. A total of 1813 individuals of Herpestomus brunnicornis (Gravenhorst) from France, Korea, and Japan were released in 1989–1991, and 26 wasps were recovered in 1994–1995. From 1989 to 1991, 2647 Diadegma armillata (Gravenhorst) individuals from France were released. D. armillata was recovered at one site in 1991 two months following release, but no other recoveries have been made. A total of 8274 Eurystheae scutellaris(Robineau-Desvoidy) individuals were released in 1989 to 1991. However, this tachinid has not been recovered. A consistent decline of AEM populations occurred in 1989–1995, including at sites where A. fuscicollis was not recovered, suggesting other factors also contributed to this pest’s decline. Now well established in western Washington, A. fuscicollis may help suppress future outbreaks of Y. malinellus and its congener, Y. padellus.     

Acceptance and suitability of four lepidopteran stemborers for the development of the pupal parasitoid Xanthopimpla stemmator (Hymenoptera: Ichneumonidae)

Xanthopimpla stemmator (Thunberg), a solitary endoparasitoid of lepidopteran stemborer pupae, was recently imported into East Africa as a candidate biological control agent of gramineous stemborers. Suitability of Busseola fusca Fuller, Chilo partellus (Swinhoe), Eldana saccharina (Walker) and Sesamia calamistis Hampson, for the development of X. stemmator was studied in the laboratory. One- to 6-day-old laboratory reared pupae of the four stemborer species were exposed to naïve X. stemmator females. All host pupae and ages were acceptable for oviposition. The parasitoids inflicted multiple probe wounds on 67.8% of pupae exposed. B. fusca, C. partellus and S. calamistis were equally suitable with 56.4, 59.4 and 52.3%, respectively, of probed pupae leading to emergence of adult parasitoids. E. saccharina was less suitable with only 22.6% of probed pupae producing parasitoids. Emergence of parasitoids did not differ significantly across the six pupal ages for B. fusca and S. calamistis, but varied for C. partellus and E. saccharina. No parasitoids emerged from 6-day-old E. saccharina pupae. Realized fecundity of females reared on the four stemborer pupae showed that fewer progeny were produced by females emerging from E. saccharina than females reared on the other three stemborer species. Eldana saccharina may be a poor host for X. stemmator in Kenya, but this parasitoid is a potential candidate for biological control of B. fusca, C. partellus and S. calamistis.     

河曲丝叶蜂形态特征、习性及防治策略

河曲丝叶蜂Nematus hequensis Xiao近年来成为北京柳树上的一种重要害虫。在检查了河曲丝叶蜂的模式标本后,发现对于雄虫的后足颜色描述有误。本文描述了各虫态的形态特征(附有彩色生态图和雌性锯腹片特征图)、调查了相关生物学特性,并提出了防治策略,重点在于树干上设置粘性胶环防治上下树的大龄幼虫和人工防治地下树干周围的茧。     

Laboratory evaluation of Orthocentrus brachycerus (Hymenoptera: Ichneumonidae), as a potential biological control agent in mushroom cultivation

Fungus gnats in the genus Neoempheria Osten Sacken (Diptera: Mycetophilidae) are serious pests of the shiitake mushroom, Lentinula edodes (Berk.) Sing. (Agaricales: Omphalotaceae), a prize edible. Recently, we found that the parasitoid wasp Orthocentrus brachycerus Humala & Lee, 2020 (Hymenoptera: Ichneumonidae) attacks larvae of Neoempheria. We have shown in previous research that O. brachycerus suppresses population growth of Neoempheria in simulated cultivation conditions, and thus shows potential for use as a biological control agent. However, the behavioural and ecological aspects of this wasp have not been studied. Here, under controlled laboratory conditions, we investigated the fecundity, longevity and host stage specificity of O. brachycerus against Neoempheria larvae. We found that O. brachycerus are prolific throughout their life cycle. On average, female O. brachycerus made over 140 attempts to parasitize pest larvae, and over 90% of Neoempheria larvae were parasitized or died before emergence. Parasitoid females kept at 20°C survived for an average of 15.4 ± 3.58 days, and some females survived >30 days. Females continued to oviposit eggs throughout their life cycle and parasitized all stages of host larvae, but not eggs. These observations indicate that O. brachycerus may be effective for control of Neoempheria larvae in shiitake cultivation facilities. These results provide a basis for establishing a protocol for using O. brachycerus in mushroom cultivation.     

Early establishment and dispersal of the weevil, Mogulones cruciger (Coleoptera: Curculionidae) for biological control of houndstongue (Cynoglossum officinale) in British Columbia, Canada

First released in Canada in 1997 to control the invasive rangeland weed, houndstongue (Cynoglossum officinale), the European root weevil, Mogulones cruciger, is showing early potential as a successful biocontrol agent. Out of 22 experimental releases in southeastern British Columbia, Canada, 100% established, regardless of initial release size (range 100-400). These founding populations persisted beyond 2 years, and quickly dispersed through a treed and variable landscape to colonise new houndstongue patches surrounding the original release patches. Within 3 years, the weevil had moved 1.42 km. Both initial, within-patch and later, between-patch dispersal followed a similar pattern, with M. cruciger adults and/or their feeding/oviposition damage being more concentrated nearest the original points of release and declining with distance. Within-patch, this pattern of distribution and also the rate of spread of weevils were similar regardless of initial release size; suggesting density-independence in dispersal behaviour at this scale. Closer investigation of the sequence of invasion at a larger spatial scale suggested that the weevil arrived at, colonized and increased in number on the closest host patches first. Three years post release, both distance from release patch and the number of M. cruciger released, were significant predictors of the amount of feeding/oviposition damage, and presumably weevil population size, within newly colonized houndstongue patches surrounding the original releases. These data, and the finding that more weevils were retrieved from patches where higher numbers of weevils were released in the previous year (i.e., 300 or 400 vs 100 or 200), suggest that release number and placement of releases within a landscape can be manipulated for effective houndstongue control.     

Interactions Between Augmentatively Released Diachasmimorpha longicaudata (Hymenoptera: Braconidae) and a Complex of Opiine Parasitoids in a Commercial Guava Orchard

A study was conducted to determine the eVect of augmentatively releasing mass-reared Diachasmimorpha longicaudata (Ashmead) on a complex of four co-existing parasitoid species which attack the oriental fruit fly, Bactrocera dorsalis (Hendel). The species belonging to this complex are the egg-pupal parasitoid, Biosteres arisanus (Sonan) and the larval-pupal parasitoids, Biosteres vandenboschi (Fullaway), D. longicaudata and Psyttalia incisi (Silvestri). The study site was a 160-ha commercial orchard of common guava, Psidium guajava L. (cv. Beaumont) located on Kauai island. One year before the release of D. longicaudata, B. arisanus was the dominant parasitoid, accounting for 91.1% of the parasitoids recovered. Despite releases of large numbers of D. longicaudata (600000-800 000 parasitized puparia/ week), B. arisanus continued to account for 90% of all parasitoids recovered from the oriental fruit fly. The larval parasitoid P. incisi may have been reduced as a result of D. longicaudata releases. D. longicaudata was significantly more abundant in over-ripe and rotting fruits compared with freshly fallen fruits. However, no increase in the overall percentage parasitism was observed in any fruit ripeness category. B. arisanus was eY cient at colonizing hosts when fruit fly densities and fruit abundance were relatively low in the orchard. The implications for future augmentative release programmes with D. longicaudata are discussed.