Parasitized Egg Masses Research Articles

The egg parasitoids, Trichogramma japonicum and Telenomus dignus, seem to have doubtful impact on the regulation of rice yellow stem borer, Scirpophaga incertulas – It is time for a reality check

The egg parasitoids, Trichogramma japonicum and Telenomus dignus, generally record a high rate of parasitism of egg masses, often 100%, but critical studies in India revealed that these, either alone or in combination, parasitized only up to 60% of the eggs in an egg mass, allowing the remaining 40% to hatch and cause potential damage. It is so because they could parasitize only those eggs that are laid on the upper surface and cannot reach out and parasitize eggs laid at the bottom layer. As a result of this inherent limitation resulting in partial parasitism of egg masses, these parasitoids, either by way of natural parasitism or artificial releases even in high numbers, seem to have a doubtful impact on the regulation of rice yellow stem borer (YSB), Scirpophaga incertulas. Tetrastichus schoenobii is also a common parasitoid of YSB, but it appears very late in the field and remains active only for a short period which greatly reduces its importance unless manipulated as suggested. It is time for a reality check and to be pragmatic in our approach in utilizing these parasitoids.

Augmentative biological control for squash bug (Hemiptera: Coreidae) using the egg parasitoid, Hadronotus pennsylvanicus (Hymenoptera: Scelionidae).

The squash bug, Anasa tristis (De Geer) (Hemiptera: Coreidae), is a serious pest of cucurbit crops across the United States. Conventional growers commonly use broad-spectrum insecticides to manage squash bugs, however organic growers lack these effective chemical tools and must rely on alternative management strategies. Biological control of A. tristis is largely understudied, specifically the potential of natural enemy, Hadronotus pennsylvanicus (Ashmead) (Hymenoptera: Scelionidae), as an augmentative biological control agent. For this reason, we performed early-season field releases of H. pennsylvanicus on organic farms in southeastern Virginia to test if this would improve A. tristis egg parasitism. We chose organic vegetable farms growing summer squash (Cucurbita pepo L.) as release sites and nearby Virginia Tech Agricultural Research Extension Centers (AREC) as no-release sites. Parasitoids were reared in the lab and deployed as parasitized egg masses (~2-3 females wasps/plant) in June 2020 and 2021. Before parasitoid deployment, host eggs collected from release and no-release sites displayed low levels of H. pennsylvanicus parasitism in 2020 (<21%) and 2021 (<8%). In both years, the percentage of A. tristis eggs parasitized within 2 weeks post deployment was significantly greater at release sites (~60%) than at no-release sites (~14%). High rates of H. pennsylvanicus parasitism (>72%) were further observed at release sites 4, 6, 8, and 10 weeks following parasitoid deployment. Our study demonstrates that releases of lab-reared H. pennsylvanicus can increase A. tristis egg parasitism rates and subsequently decrease successful nymph hatch rates in early summer squash plantings.

Predation and parasitism of naturally occurring and sentinel stink bug egg masses ofHalyomorpha halys(Stål) andNezara viridula(L.) (Hemiptera: Pentatomidae) in various southeastern habitats

Stink bugs, including Halyomorpha halys (Stål) and Nezara viridula (L.), are agricultural pests that feed on fruit in a variety of crops. Monitoring predation and parasitism of stink bug egg masses furthers our understanding of potential biological control tactics. However, best practices for laboratory and field assessments of parasitism and predation of egg masses require further attention. We carried out a series of laboratory and field experiments to test whether parasitism and predation for three types of sentinel H. halys egg masses, fresh, frozen, and refrigerated, varied in agricultural commodities. In addition, we asked if predation and parasitism differed between sentinel and naturally occurring H. halys and N. viridula egg masses in soybean. In the laboratory, more H. halys eggs were parasitized by Trissolcus euschisti (Ashmead) (Hymenoptera: Scelionidae) if they were frozen or refrigerated compared to fresh eggs. Similarly, in the field, parasitism was higher for frozen egg masses than fresh. In 2018 and 2019, H. halys natural egg masses had higher parasitism and lower predation compared to sentinel egg masses in soybean. In a paired field test during 2020 and 2021, there was no difference in parasitism between H. halys natural and sentinel eggs, but much higher incidence of parasitism was detected in natural N. viridula egg masses than sentinel eggs. Collecting natural egg masses is the best methodology for field assessment of parasitism of stink bug egg masses; however, if natural egg masses are not easily available, deploying refrigerated sentinel egg masses is a good alternative.

First discovery of the natural egg parasitoid of Cydalima perspectalis (Walker, 1859) in Turkey with molecular methods (Lepidoptera: Crambidae

The genus Trichogramma Westwood, 1833 are important biological control agents of especially Lepidoptera pests in all around the world. These tiny wasps can’t be reliably identified owing to their small size and lack of definable morphological characters. ITS2 (Internal transcribed spacer 2) sequence-based identification has been performed successfully for years for parasitoids of the genus Trichogramma. The use of indigenous Trichogramma species against pests is very important for the success of biological control. Therefore, accurate and precise species identification of Trichogramma plays a key role in biological control programs. In the study, egg parasitoids were obtainedfrom parasitized egg masses of Cydalima perspectalis (Walker, 1859) collected in Hatay province of Turkeyin May 2021. Trichogramma wasps were collected and only one species was determined by using both ribosomaland mitochondrial sequences. According to ribosomal and mitochondrial sequence results, all of the collectedsamples were determined to be Trichogramma evanescens Westwood, 1833. This is the first report of T. evanescensas egg parasitoid of C. perspectalis in the worldwide.

Effect of Duration of Deployment on Parasitism and Predation of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) Sentinel Egg Masses in Various Host Plants

The invasive brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), is an agricultural and nuisance pest in Georgia and Alabama, USA. Natural enemies may provide significant suppression of the brown marmorated stink bug, and sentinel egg masses are deployed commonly on plants in the field to measure their effects. The objective of this study was to evaluate the effect of deployment duration (2–5 d) on parasitism and predation of brown marmorated stink bug sentinel egg masses in plum, peach, blueberry, tomato, sassafras, corn, and soybean in these 2 states. Retrieved egg masses were processed to quantify rates of predation and parasitism and identify parasitoid species and predation types. Across crops, predation and parasitism were higher significantly in plum at 5 d compared to 2 d deployment but was similar in soybean regardless of exposure time in 2017. Predation and parasitism were higher significantly after 5 d of exposure compared to 2 d and 3 d whereas parasitism was significantly higher at 3 d compared to 2 d exposure in 2018 to 2020. For individual crop trials, though, effects of time of exposure were tested in different yr, sampling dates, and crops with variable results. When significant differences were detected for parasitism in plum, peach, tomato, and sassafras, a 5 d deployment resulted in higher parasitism compared to 2 d. Given the variability of factors that affect parasitism and predation under field conditions, we conclude that a 5 d deployment is optimal and a 3 d exposure time is minimal for assessing predation and parasitism. An additional benefit for a 5 d exposure is that it increases the probability of detecting hyperparasitism.

A temporal trophic shift from primary parasitism to facultative hyperparasitism during interspecific competition between two coevolved scelionid egg parasitoids.

Understanding competition between scelionid parasitoids that exploit the same host may provide insight into strategies that allow coexistence on a shared resource. Competition studies typically focus on interactions between native and exotic parasitoids that do not share an evolutionary history; however, coevolved parasitoids may be more likely to demonstrate strategies to avoid or exploit a shared resource. We examined intrinsic and extrinsic competition between Asian Trissolcus japonicus (Ashmead) and T. cultratus (Mayr) (Hymenoptera: Scelionidae) associated with Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) that share an evolutionary history. Interspecific interactions were assessed by providing parasitized egg masses to each species at various intervals post‐parasitism, and measuring host acceptance, developmental suitability, and guarding behaviour. Trissolcus japonicus showed high acceptance of parasitized hosts up to 72 h following oviposition by T. cultratus, despite a very poor developmental outcome. In contrast, T. cultratus generally avoided ovipositing in H. halys eggs containing T. japonicus early‐instar larvae but did not avoid parasitizing H. halys that contained eggs and third instar larvae. The adaptive value of this behaviour was supported by developmental outcome: T. cultratus outcompeted T. japonicus eggs but not early‐instar larvae, and a trophic shift occurred wherein T. cultratus developed as a facultative hyperparasitoid on third instar T. japonicus larvae. Trissolcus japonicus guarded egg masses 8–12× longer and displayed more aggressive interactions than T. cultratus, suggesting T. japonicus is the superior extrinsic competitor. Development as a facultative hyperparasitoid provided a competitive niche for Asian T. cultratus and confirms its instrinsic competitive superiority. This also occurs in a biologically distinct European population of T. cultratus, suggesting that facultative hyperparasitism as a competitive strategy is retained in geographically separated populations that have not coevolved with H. halys or T. japonicus.

Assessing the Potential of Inoculative Field Releases of Telenomus remus to Control Spodoptera frugiperda in Ghana.

Simple SummaryThe fall armyworm (FAW) is a serious threat to maize production in Africa following its outbreak in 2016. Fortunately, some beneficial insects that could control FAW are already present in Africa, including Telenomus remus which parasitizes FAW eggs. Telenomus remus has been used in South America for biological control of FAW for several decades. Though T. remus is already present in Africa, little is known about its potential to be used for augmentative biological control of FAW under ecological conditions and agricultural systems in Africa. This study contributed to addressing this knowledge gap by conducting replicated field release trials of T. remus for FAW control in large maize plots in Ghana. In the major and minor rainy seasons, T. remus parasitized up to 33% and 100% of FAW egg masses, respectively, in the release plots. However, similar effectiveness of T. remus was recorded in non-treated control and farmers’ plots located at 150–400 m distance from release plots, indicating high dispersion of the parasitoid. A single application of Emamectin benzoate did not significantly affect the parasitism rates of T. remus, and could be considered in IPM strategies against FAW.In response to the threat caused by the fall armyworm to African maize farmers, we conducted a series of field release studies with the egg parasitoid Telenomus remus in Ghana. Three releases of ≈15,000 individuals each were conducted in maize plots of 0.5 ha each in the major and minor rainy seasons of 2020, and compared to no-release control plots as well as to farmer-managed plots with chemical pest control. No egg mass parasitism was observed directly before the first field release. Egg mass parasitism reached 33% in the T. remus release plot in the major rainy season, while 72–100% of egg masses were parasitized in the minor rainy season, during which pest densities were much lower. However, no significant difference in egg mass parasitism was found among the T. remus release plots, the no-release control plots and the farmer-managed plots. Similarly, no significant decrease in larval numbers or plant damage was found in the T. remus release fields compared to the no-release plots, while lower leaf and tassel damage was observed in farmer-managed plots. Larval parasitism due to other parasitoids reached 18–42% in the major rainy season but was significantly lower in the minor rainy season, with no significant differences among treatments. We did not observe significant differences in cob damage or yield among the three treatments. However, the lack of any significant differences between the release and no-release plots, which may be attributed to parasitoid dispersal during the five weeks of observation, would require further studies to confirm. Interestingly, a single application of Emamectin benzoate did not significantly affect the parasitism rates of T. remus and, thus, merits further investigation in the context of developing IPM strategies against FAW.

Host finding behaviour of the egg parasitoid, Gryon pennsylvanicum (Hymenoptera: Scelionidae)

ABSTRACT The squash bug, Anasa tristis (De Geer) is a serious pest of cucurbit crops. The egg parasitoid, Gryon pennsylvanicum (Ashmead), is the primary parasitoid of the squash bug and has been considered as a biological control agent. In the present study, we conducted both laboratory and greenhouse bioassays to determine the effects of kairomones emitted by A. tristis on the host searching behaviour of G. pennsylvanicum. Chemicals were extracted from A. tristis eggs, unmated females and males, and mated females and males. The percentage of females responding to extracts was significantly higher for egg extracts than the other extracts tested. In greenhouse tests, percent parasitism of egg masses baited with extract-treated lures was significantly higher than for those treated with solvent-treated control lures for all six extracts tested: ethanol and hexane extracts of eggs, mated females and mated males. Further research on kairomones of A. tristis may result in the development of synthetic lures that could be used in squash fields to increase parasitism by G. pennsylvanicum. The promising results from this study highlights the potential application of kairomones in enhancing the efficacy and effectiveness of biological control programmes and should be of interest to growers and pest control professionals.

Biopesticide and Parasitoid Effects on Megacopta cribraria (Hemiptera: Plataspidae) Life Stage Density and Egg Parasitism in Soybean

Biopesticide and Parasitoid Effects on <i>Megacopta cribraria</i> (Hemiptera: Plataspidae) Life Stage Density and Egg Parasitism in Soybean

Responses of native egg parasitoids to the invasive seed bug Leptoglossus occidentalis

Abstract The Western conifer seed bug Leptoglossus occidentalis, a native insect of North America, was accidentally introduced in Europe in the late 1990s. Since then, it has spread rapidly. Biological control could provide an efficient management option but natural enemies of the pest have been poorly examined in Europe. In this study, we exposed sentinel egg masses and collected naturally laid egg masses in southern France in 2016 and 2017, to identify the egg parasitoids of L. occidentalis and investigate their potentials. Three egg parasitoids were detected: Anastatus bifasciatus, Ooencyrtus pityocampae and Ooencyrtus telenomicida. The overall parasitism was low compared to that observed in the native range with 6.4% of all eggs being parasitized, while 17.1% of egg masses carried at least one parasitized egg. The total number of parasitized egg masses was similar between parasitoid species, but the mean number of parasitized eggs per egg mass was highest for A. bifasciatus (5.57 vs. 1.25 for Ooencyrtus spp.). Sentinel egg masses underestimated the parasitism compared to natural egg masses (respectively, 1.42% and 7.71%). Our results suggested that the three generalist parasitoids detected can respond in a Leptoglossus egg density‐dependent manner, but this requires further investigations.

Parasitism and Predation on Sentinel Egg Masses of Three Stink Bug Species (Hemiptera: Pentatomidae) in Native and Exotic Ornamental Landscapes.

This study evaluated parasitism and predation on sentinel egg masses of three stink bug species, the spined soldier bug, Podisus maculiventris (Say), the brown stink bug, Euschistus servus (Say), and the invasive brown marmorated stink bug (BMSB), Halyomorpha halys (Stål), in ornamental landscapes composed of either native or exotic plants. This study also compared the species composition of parasitoids attacking two native stink bug species (P. maculiventris and E. servus) with those attacking the invasive BMSB on the same tree species in the same habitat. Overall, egg parasitism and predation were much higher on the two native stink bug species compared with BMSB, with an average parasitism rate of 20.6% for E. servus, 12.7% for P. maculiventris, and only 4.2% for H. halys and an average predation rate of 8.2% for E. servus,17.7% for P. maculiventris, and 2.3% for H. halys. Egg predation was also significantly higher on P. maculiventris than on E. servus eggs. Eight parasitoid species attacked sentinel stink bug eggs in the ornamental landscaped plots. Trissolcus euschisti (Ashmead) (Hymenoptera: Scelionidae) was the predominant parasitoid for all three stink bug species. There were no significant differences in parasitism and predation rates on any of the stink bug species between native and exotic plots. Therefore, there is no evidence that ornamental landscapes composed of native plants increased parasitism or predation rates of sentinel egg masses of two native stink bug species or the invasive BMSB, compared with those composed entirely of exotic plants.

Integrating Trissolcus japonicus (Ashmead, 1904) (Hymenoptera: Scelionidae) into Management Programs for Halyomorpha halys (Stål, 1855) (Hemiptera: Pentatomidae) in Apple Orchards: Impact of Insecticide Applications and Spray Patterns.

Simple SummaryIn the United States, the invasive brown marmorated stink bug has caused economic damage to specialty crop and tree fruit industries, including apples. Since its arrival, research has shown that altered spray programs can control brown marmorated stink bug as well as spraying an entire apple orchard, resulting in less insecticide use. Here, we evaluated three spray programs and four commonly used insecticides in combination for their impact on a non-native wasp, the samurai wasp, that parasitizes egg masses of this invasive stink bug. We exposed adult samurai wasps to egg masses from our treatments, including unsprayed areas, and recorded their survival as well as how many wasps emerged afterward. In addition, we recorded how immature wasps developing inside egg masses responded to these treatments. We found that only one insecticide had negative impacts on the adult wasps while the majority of insecticides tested impacted their offspring’s emergence. In general, insecticides tested minimally impacted wasps already developing inside egg masses treated with insecticides. These data support the idea that growers can simultaneously manage brown marmorated stink bug and conserve beneficial insects, such as the samurai wasp, while reducing insecticide use by using improved pest management tactics.Halyomorpha halys (Stål, 1855) (Hemiptera: Pentatomidae) is an invasive species in the United States, where it has caused significant damage to specialty crops, including apples. While integrated pest management techniques have been developed for H. halys in apple, including spray application techniques, it is unknown how these techniques affect foraging, adventive Trissolcus japonicus (Ashmead, 1904) (Hymenoptera: Scelionidae), and its offspring. In this study, egg masses (unparasitized and 2 and 7 day parasitized pre-treatment) were placed in apple orchards in treated and untreated locations that received full block insecticide applications or reduced application techniques, including border row or alternate row middle applications. Bifenthrin, thiamethoxam + λ-cyhalothrin, clothianidin, and methomyl were evaluated. Egg masses were retrieved 24 h after spray applications. For 2 and 7 day parasitized pre-treatment, adult T. japonicus emergence was recorded from each egg mass. For unparasitized egg masses, T. japonicus females were given 24 h to forage and oviposit on post-treatment egg masses with female survivorship, and adult emergence from egg masses was recorded. Female survivorship was significantly lower on post-treatment egg masses retrieved from areas receiving bifenthrin applications. Emergence from post-treatment egg masses was affected by thiamethoxam + λ-cyhalothrin, bifenthrin, and methomyl in some treated areas, whereas less impact was observed on 2 and 7 day pre-treatment parasitized egg masses in general. These data provide further insights into H. halys management and the potential impact of T. japonicus in sprayed orchard agroecosystems.

An investigation of Caligula japonica (Lepidoptera: Saturniidae) egg distribution and associated parasitoids on walnut trees (Juglans regia L.) in northwestern China

Caligula japonica is a serious defoliator pest of walnut trees, Juglans regia, in China. Important information about the occurrence of C. japonica egg masses on host plants and their indigenous parasitoids under field conditions are rarely documented. Here the distribution of egg masses of C. japonica on the trunks of J. regia and occurrence of its parasitoids in Kangxian, the most important walnut production area in northwestern China, were investigated. The results revealed that the egg masses were mainly located at 109.2 ± 62.3 cm height. The number of egg masses exhibited a significant positive linear relationship with the diameter of trees and a parabolic relationship with host tree height. The natural parasitism rate showed a significant negative linear relationship with the size of egg masses but no relationship with the height of egg masses. The percentage of parasitized egg masses and parasitism percentage of eggs were 49.0% and 7.0%, respectively. We found seven egg parasitoid species belonging to three genera, in which Mesocomys trabalae had the largest Berger-Parker index (0.6963). In addition, the coparasitism of M. trabalae and M. albitarsis accounted for 39.7% of the total coparasitized egg masses. This investigation provides basic information for utilizing egg parasitoids against C. japonica in the future.

Assemblage of the Egg Parasitoids of the Invasive Stink Bug Halyomorpha halys: Insights on Plant Host Associations.

Simple SummaryThe Brown Marmorated Stink Bug (BMSB), Halyomorpha halys, is an invasive polyphagous species that causes extensive damage to fruits and vegetable crops. Available chemical treatments and mechanical measures are often insufficient to keep this pest under control. In the last decade, the scientific community has made several efforts in order to identify and select suitable natural enemies to use in biological control program. Several native and exotic parasitoid species attacking H. halys eggs have been registered in the invaded countries. In this study, the distribution of these parasitoids was examined in Trentino-Alto Adige, in Northern Italy, by combining two different methods. The research revealed the presence of seven parasitoid and one hyperparasitoid species, which are present in different contexts and on several host plants. The most abundant species, Anastatus bifasciatus and Trissolcus mitsukurii, showed different patterns in distribution, with a higher presence of A. bifasciatus in urban areas and Tr. mitsukurii in orchards. Our results proved that H. halys natural enemies are adapted to the environmental conditions of the study area. The gathered data on the plant host-associations will support the development of future biological control programs.Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) is an invasive alien species and a key agricultural pest. Its native parasitoids (Trissolcus japonicus Ashmead and Tr. mitsukurii Ashmead) have been registered in several countries where H. halys brought dramatic economic losses and where biological control is considered to be the most effective long-term solution. By searching for stink bug egg masses and exposing sentinel egg masses, we monitored the distribution of native and exotic egg parasitoids in Trentino-Alto Adige (Italy), an area where both the host and parasitoids are in expansion. We recorded ten pentatomids, seven parasitoid species, with the first report of Tr. japonicus in this area and a hyperparasitoid. In the assemblage, Anastatus bifasciatus (Geoffroy) and Tr. mitsukurii were the dominant parasitoids, with a different distribution in terms of context and host plants. Sycamore was the host plant where the highest number of naturally laid parasitized egg masses (26%) were recorded. Trissolcus mitsukurii showed the highest parasitism rate, and was often found in apple orchards. The emergence of exotic parasitoids showed a temporal delay compared to native ones. Sequence analysis of 823 bp of the CO1 mitochondrial gene revealed that the recovered Tr. japonicus and Tr. mitsukurii harbored one single haplotype each. These haplotypes were previously found in 2018 in Northern Italy. While sentinel egg masses proved to be very effective in tracking the arrival of exotic Trissolcus species, the collection of stink bug egg masses provided fundamental data on the plant host species. The results lend strong support to the adaptation of exotic Trissolcus species to the environmental conditions of the range of introduction, providing new information on plant host-associations, fundamental for the development of biological control programs.

Molecular identification of Trichogramma species parasitizing Ostrinia nubilalis in corn and pepper in south–east border of Europe

The current study extends the faunistic survey of Trichogramma species parasitizing ECB to all agricultural growing regions in Serbia. Specimens of Trichogramma were reared from parasitized egg masses of ECB collected from field-grown corn and pepper crops. The number of egg masses parasitized varied by location. Using sequences of mitochondrial cytochrome oxidase I (COI) gene, we examined intra and interspecific variation in Trichogramma parasitizing the ECB egg masses. Seventy specimens were successfully sequenced of which, 65 were identified as T. brassicae. The remaining five were identified as T. evanescens, and this second species was only collected from pepper.

Incidence of egg and larval parasitoids of Chilo partellus on Kharif maize

The incidence of egg and larval parasitoids of Chilo partellus was monitored in insecticide free maize fields at the Indian Agricultural Research Institute, New Delhi, for three Kharif seasons of 2013 to 2015. The hymenopteran parasitoid, Trichogramma sp. was recorded to be the only egg parasitoid in this area, while a good number of larvae were parasitized by braconid, Cotesia flavipes . The egg parasitism was recorded on the freshly laid eggs of stem borer obtained by artificially releasing the adults of C. partellus on maize cultivars, HQPM1 and PMH1, at 12 days after germination. There was no egg parasitism recorded during Kharif 2013 and 2014, whereas 5.6 percent egg-mass parasitism by Trichogramma sp. was recorded during Kharif , 2015. The larval parasitoids were monitored by artificially infesting the maize plants with neonates of laboratory reared C. partellus . The larvae were allowed to develop on maize plants under field conditions for 20 days. The plants showing stem borer damage were cut and brought to the laboratory. The larvae collected from infested maize plants were reared in the laboratory. The maggots of C. flavipes recovered from parasitized larvae ranged from 29-100, 41-50 and 20-80 percent during Kharif 2013, 2014 and 2015, respectively. The result of this study indicated that parasitism by Cotesia was influenced by age of plants damaged by C. partellus . The young maize plants seemed to be more attractive to the foraging of Cotesia and more stem borer larvae were parasitized on these plants as the maximum (58 percent) parasitism was observed at 40-day-old crop. The parasitoid was found to be active on maize from 40-60 days after germination and the incidence decreased thereafter. Insecticides should not be used during this period. The current studies also revealed that host densities had no significant effect on percentage parasitism by Cotesia .

Telenomus remus, a Candidate Parasitoid for the Biological Control of Spodoptera frugiperda in Africa, is already Present on the Continent

The fall armyworm, Spodoptera frugiperda, a moth originating from tropical and subtropical America, has recently become a serious pest of cereals in sub-Saharan Africa. Biological control offers an economically and environmentally safer alternative to synthetic insecticides that are being used for the management of this pest. Consequently, various biological control options are being considered, including the introduction of Telenomus remus, the main egg parasitoid of S. frugiperda in the Americas, where it is already used in augmentative biological control programmes. During surveys in South, West, and East Africa, parasitized egg masses of S. frugiperda were collected, and the emerged parasitoids were identified through morphological observations and molecular analyses as T. remus. The presence of T. remus in Africa in at least five countries provides a great opportunity to develop augmentative biological control methods and register the parasitoid against S. frugiperda. Surveys should be carried out throughout Africa to assess the present distribution of T. remus on the continent, and the parasitoid could be re-distributed in the regions where it is absent, following national and international regulations. Classical biological control should focus on the importation of larval parasitoids from the Americas.

First Report of Trissolcus japonicus Parasitizing Halyomorpha halys in North American Agriculture

Halyomorpha halys (Stal) (Hemiptera: Pentatomidae), the brown marmorated stink bug, an invasive agricultural pest in America and Europe, is reaching a global distribution. In the US, the first detection of H. halys was in the mid–1990s, and it has become a serious pest in multiple crop systems. In 2014, an exotic egg parasitoid, Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), was documented parasitizing sentinel H. halys egg masses in a wooded habitat in Beltsville, Maryland, USA. The parasitoid has since been reported in several other locations in the eastern and western US, and its population appears to be expanding in geographic range. However, there have been no reports of T. japonicus parasitizing H. halys egg masses within cultivated crops in the US. Whereas attack of H. halys in non-agricultural habitat may provide important biological control services in the landscape, if T. japonicus is not able to successfully forage for H. halys eggs within crops, its impact as a biological control agent may be limited. Here we report on successful parasitism of egg masses deployed in 2 peach orchards in New Jersey, USA. Egg masses were deployed as part of an experiment investigating the efficacy of an integrated pest management (IPM) strategy utilizing border insecticide sprays in apple and peach. While overall egg parasitism was low, the majority of successfully developing parasitoids (97.4% of total adult parasitoids emerging, and from 75% of successfully parasitized sentinel egg masses) were T. japonicus.

Occurrence of Telenomus dignus (Gahan) on the Sugarcane Borers, Scirpophaga intacta Snellen and Chilo sacchariphagus Bojer in Guangxi Province, China

Sugarcane (Saccharum officinarum L.) is an important crash crop in Guangxi, China. The sugarcane borers (Scirpophaga intacta Snellen and Chilo sacchariphagus Bojer) cause serious damage to sugarcane crop in Guangxi Province. Consequently, increasing attention has been given into the investigation and development of biocontrol agents to control these pests. The parasitoid wasp Telenomus sp. has previously been reported as a natural enemy of sugarcane borers in Guangxi Province. Telenomus dignus is the species found parasitizing borer eggs in field in Fujian Province, but it has not been previously mentioned as natural enemy of these pests. T. dignus was collected on S. intacta egg masses and identified from Shangsi County of Guangxi Province during 2013. In these studies, the parasitic behavior of T. dignus on eggs of S. intacta and C. sacchariphagus was investigated under field conditions during 2013–2014. The results from the current study showed that the percentage of parasitized egg masses of S. intacta parasitized by T. dignus was 45.71 and 57.14% in 2013 and 2014, respectively, while in C. sacchariphagus egg masses, the percentage of parasitism by T. dignus was 45.28 and 51.09% in 2014, respectively. The sex ratio (female/male) of T. dignus adults on S. intacta was 1.45:1 in 2013 and 5.17:1 in 2014 and was 2.17:1 on C. sacchariphagus in 2014. T. dignus was the dominant egg parasitoid of these two species of sugarcane borers in isolated sugarcane regions in Guangxi Province. Further investigations on biology of T. dignus are required to develop this parasitoid as a more widespread biocontrol agent of sugarcane borers.

Spatial Distribution of Megacopta cribraria (Hemiptera: Plataspidae) Adults, Eggs and Parasitism by Paratelenomus saccharalis (Hymenoptera: Platygastridae) in Soybean.

Since 2014, populations of the kudzu bug, Megacopta cribraria (F.) (Hemiptera: Plataspidae), have declined in the southeastern United States and seldom require treatment. This decline follows the discovery of Paratelenomus saccharalis (Dodd; Hymenoptera: Platygastridae), a non-native egg parasitoid. The objective of this project was to observe the temporal and spatial dynamics of P. saccharalis parasitism of kudzu bug egg masses in commercial soybean fields. Four fields were sampled weekly for kudzu bugs and egg masses at a density of one sample per 0.6 ha. Sampling commenced when soybean reached the R2 maturity stage and continued until no more egg masses were present. Responses including kudzu bugs, egg masses, and parasitism rates were analyzed using ANOVA, Spatial Analysis by Distance Indices (SADIE), and SaTScan spatial analysis software. Egg masses were collected from the field, held in the lab and monitored for emergence of kudzu bug nymphs or P. saccharalis. Kudzu bug populations were generally lower than previously reported in the literature and spatial aggregation was not consistently observed. Egg parasitism was first detected in early July and increased to nearly 40% in mid-August. Significant spatial patterns in parasitism were observed with spatio-temporal clusters being loosely associated with clusters of egg masses. There were no significant differences in parasitism rates between field margins and interiors, suggesting that P. saccharalis is an effective parasitoid of kudzu bug egg masses on a whole-field scale.