Native Parasitoids Research Articles

Current Advances in Biology, Distribution, and Management of Melanaphis sacchari (Zehntner)1 in México and United States of America

The sugarcane aphid, Melanaphis sacchari (Zehntner), is a major insect pest of sorghum (Sorghum bicolor (L.) Moench) in Mexico and United States of America. This review reports current advances for the biology of the aphid, crop damage, and sampling strategies to detect the pest. We focused on management through cultural control including resistant varieties, biological control with native parasitoids and predators and use of entomopathogenic fungi, legal control, and chemical control. Life stages of the aphid are nymph, nymphal alate, super nymph, and adult. Females have parthenogenetic reproduction and under adverse conditions, viviparous reproduction. Damage to the sorghum crop by feeding nymphs and adults causes stress to the plants and yield loss. To detect the pest, leaves should be sampled each week or yellow traps used with soapy water to monitor arrival of winged adults. Cultural practices recommended are destroying foci of infection and using established official planting dates and appropriate fertilization. Currently, the main control strategy is foliar application of insecticides. However, numerous species of predators, parasitoids, and entomopathogenic fungi affect sugarcane aphids in the USA and Mexico. The organisms could sustain control of the aphid, but few have been evaluated in the field. Studies of sorghum varieties in areas of México and the USA allowed identification of genotypes with resistance to sugarcane aphids. Considering sampling strategies, biology, and life cycle studies, search for an organism with potential for biological control of M. sacchari, and identification of sorghum genotypes with resistance to damage, it is possible to develop an integrated management strategy against sugarcane aphid. For future research, it is important to develop bioassays for monitoring resistance to insecticide, study interaction between factors that favor natural and induced control with natural enemies, and promote planting of sorghum genotypes with resistance.

Differential biocontrol efficacy of the parasitoid wasp Campoletis sonorensis on the Fall Armyworm Spodoptera frugiperda feeding on landrace and hybrid maize

ABSTRACT Maize is an important cereal crop worldwide. In Mexico, both hybrid and native genotypes are grown. Insect herbivory, mainly by the larvae of Spodoptera frugierda L, impose significant yield losses. Developing pest control strategies using natural enemies in an agroecological approach offers an environmentally sound alternative to minimise the input of pesticides in maize agroecosystems. Campoletis sonorensis is a native parasitoid that has shown significant control efficiency on S. frugiperda in the field, but many aspects of its ecology are largely unknown. In a controlled greenhouse experiment, we investigated the biocontrol efficacy of C. sonorensis in S. frugiperda feeding on four maize genotypes (two landraces and two hybrids). Our main results showed that maize genotype significantly affected C. sonorensis parasitism of S. frugiperda and consequently damage from herbivory. C. sonorensis diminished herbivore damage in all studied maize genotypes, and this effect was strongest in the maize hybrid PUMA. Our results show that the biocontrol efficacy of C. sonorensis against S. frugiperda is affected by the maize genotype, which should be further examined under field conditions.

Color, odor, and species preferences of Copidosoma bakeri to prospective cover crops to enhance control of cutworms

AbstractCutworms (Lepidoptera: Noctuidae) are economically important pests of multiple field crops, but are difficult to control with insecticides. Biological control with native parasitoids may offer a sustainable alternative for pest management. Cover crops improve the availability of resources required by parasitoids to increase their effectiveness as biocontrol agents. Copidosoma spp. (Hymenoptera: Encyrtidae) have the potential to control several species of cutworms in the Canadian Prairies. However, their foraging preferences for non‐host food items are unknown. In this study, we tested flower color and odor preferences of Copidosoma bakeri (Howard) across nine potential cover crop species and investigated how these resources affect survival and longevity of the female wasps. Results indicated that the wasps were most attracted to plants with yellow flowers in the family Brassicaceae (i.e., camelina, mustard, and canola). In multiple‐choice tests, the wasps preferred camelina over all other flower species, and showed an intermediate preference for mustard and canola. In dual‐choice tests with color paper, the wasps preferred yellow over white, and the light yellow of camelina over the bright yellow of canola and mustard, whereas they showed a preference for the odors of mustard and canola. Life expectancy was increased when the wasps were provided floral resources compared to the absence of a food source. Later planting dates and mixed‐species plantings of cover crops resulted in flowering times that better coincided with native wasp emergence. Camelina is known to suppress weeds and may be used as a habitat management tool for enhancing parasitism of cutworms by C. bakeri in the Canadian Prairies. However, further testing is needed to achieve late flowering well into August and early September and to ensure planting additional Brassica spp. does not attract more late‐season pests to cash crops such as canola.

Seasonal Captures of Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) and the Effects of Habitat Type and Tree Species on Detection Frequency.

Simple SummaryTrissolcus japonicus, an important natural enemy of brown marmorated stink bug in Asia, was first detected in the USA in 2014. To investigate when and where T. japonicus is found in the field, yellow sticky traps were deployed in the canopy of tree of heaven growing at the edge of small isolated patches, windbreaks, and woodlots in 2018 and 2019. In both years, captures occurred from May to September, with peaks in July and August. Captures of T. japonicus were recorded from all three habitats but were not consistently associated with a particular habit. In 2017 and 2018, T. japonicus captures were compared between tree of heaven paired with several other H. halys host trees growing at the woods edge, and in 2019, captures in tree of heaven, black walnut, and black locust growing in the same windbreaks were compared. Trissolcus japonicus and several native H. halys parasitoids were captured in all hosts, but there was not a consistent effect of host tree species on T. japonicus captures. These results can be used to inform and optimize future surveillance efforts for detecting T. japonicus as it continues to expand its range in the USA.Trissolcus japonicus, an important egg parasitoid of Halyomorpha halys in Asia, was first detected in the USA in 2014. To evaluate the effect of habitat and the seasonality of T. japonicus detections in the USA, yellow sticky traps were placed in the canopy of Ailanthus altissima growing at the edge of isolated patches of trees, windbreaks, and woodlots in northern Virginia in 2018 and 2019. In both years, captures occurred from May to September, and peaked in July and August. While T. japonicus was detected in all habitats, there was not a consistent effect of habitat type on capture frequency. To evaluate tree species effects on T. japonicus captures, in 2017 and 2018, yellow sticky traps deployed in the canopy of A. altissima bordering apple orchards were paired with a nearby trap in one of several wild tree species along a common woods edge. In 2019, these traps were deployed in A. altissima, black walnut, and black locust growing in the same windbreaks. No consistent association between captures of T. japonicus or native parasitoids of H. halys and the tree species sampled was observed among years. Results are discussed in relation to the ecology and sampling optimization of T. japonicus.

Gall size of Dryocosmus kuriphilus limits down-regulation by native parasitoids

The success of invasive species largely depends on the resistance offered by the native communities. Dryocosmus kuriphilus is a cynipid native from China that is a serious pest of chestnuts worldwide. This species recruits natural enemies in the areas of introduction; nevertheless, their role in regulating pest population is frequently questioned, although the causes are not clear. We sampled parasitoids from 12,525 galls collected in 192 sites in four geographic areas differing in climate and residence time of the wasp of Galicia (NW Iberian Peninsula). We also dissected 2994 galls to assess the effects of gall characteristics on parasitism level. We found a rich community of native enemies that contributed to biotic resistance against the invasive: 19 species of native parasitoids were feeding on the wasp, with mortalities ranging from 14 to 37%. Rarefaction analyses indicated that this species list accounts for most of the native enemies that attack D. kuriphilus in inland Galicia. However, percent parasitism of D. kuriphilus by native parasitoids decreased greatly with time since introduction. This was because galls became larger, more thickly walled, and with more D. kuriphilus per gall as the abundance of D. kuriphilus increased. As the galls became larger and more populated, a declining fraction of the D. kuriphilus within were parasitized by native enemies (decrease from > 25% parasitism to < 2% as gall size increased from 0.2 to 3 cm3). Consequently, native parasitoids may play a role in slowing the invasive at low densities, but this effect becomes increasing inconsequential in highly invaded areas.

Exploration of a biological control agent and evaluation of conventional control measures to manage cucumber moth, an emerging pest of cucurbitaceous vegetables in Bangladesh

Cucumber moth, Diaphania indica (Crambidae: Lepidoptera) is a serious pest of cucurbitaceous vegetables in many countries. This pest has also been reported in Bangladesh. However, no proper effort has been made to manage it successfully. Inappropriate control measures may increase the management costs as well as detrimental to the environment and non-target organisms. Larvae of D. indica, larvae were collected from the field and reared in the lab to find out natural control agents. About 41% larvae were found parasitized by a natural parasitoid, Apanteles taragamae. On an average, 16 parasitoid adults were developed from a single parasitized larva. Efficacy of commonly used control measures (such as neem oil, mahogany oil, handpicking, deltamethrin insecticide and cypermethrin insecticides) were evaluated against D. indica in the field on snake gourd and ridge gourd. All control measures produced significant differences to reduce per cent leaf infestations and the number of larvae per plants comparing to the untreated control plants. Among the treatments, neem oil and deltamethrin were found highly effective. Mahogany oil and cypermethrin were found as moderately effective and handpicking was found as least effective among the treatments. Neem oil-cum-deltamethrin approach can be recommended to control D. indica. Use of A. taragamae will give sustainable management of D. indica if commercial release is available.

Differences in native and introduced chalcid parasitoid communities recruited by the invasive chestnut pest Dryocosmus kuriphilus in two Iberian territories

Dryocosmus kuriphilus (Hymenoptera: Cynipidae) is a global invasive gall wasp and a pest of chestnuts (Castanea spp.). A study of the Chalcidoidea parasitoid community of D. kuriphilus was undertaken over two years, from March 2017 to March 2019, at 15 sites in south and northwest Spain (Málaga and Galicia regions). More than 18,000 galls were collected, and 1153 parasitoids belonging to 22 species of seven chalcidoid families, plus two individuals of an inquiline Cynipidae, Synergus facialis, emerged. Richness was higher in the Málaga region, with 20 species, while 17 parasitoids and one inquiline were identified in Galicia. The parasitism rate of native chalcid parasitoid species in both regions was low. Eupelmus urozonus and Mesopolobus lichtensteini were the most abundant native species. Mesopolobus tibialis was a dominant species in south Spain, while Ormyrus pomaceus was a dominant species in northwest Spain. Our results revealed the existence of a sub-community of univoltine, probably host specialized, parasitoids in south Spain, which overwinter in galls, exhibiting a similar life cycle to Torymus sinensis. These species were Torymus notatus, Aulogymnus bicolor, Aulogymnus obscuripes and Aulogymnus balani. Data on the recovery of T. sinensis after release in the south Spain region show it to be well established, but its numbers are still low in northwest Spain.

Competition between Diachasmimorpha kraussii and Fopius arisanus in Bactrocera tryoni: does native parasitoid-host association matter?

In Australia Fopius arisanus (Sonan) is an established, but exotic fruit fly egg-larval-pupal parasitoid which co-occurs with Diachasmimorpha kraussii (Fullaway), a native larval-pupal fruit fly parasitoid: both attack the native fruit fly Bactrocera tryoni (Froggatt). In interactions involving evolutionary novel host-parasitoid associations, F. arisanus consistently out-competes other parasitoid species, including D. kraussii. However, in fruit fly-parasitoid systems where there is co-evolutionary history between parasitoids and their hosts, competitive hierarchies can vary. In this study we investigated the outcome of competition between F. arisanus and D. kraussii within B. tryoni, to test whether the close evolutionary relationship between D. kraussii and B. tryoni might circumvent the competitive advantage of F. arisanus. Consistent with previous research, and despite the evolutionary relationship, dissection of multiparasitized B. tryoni larvae showed that D. kraussii was invariably suppressed by F. arisanus. A total of 47% and 74% of the eggs of D. kraussii in presence of F. arisanus were killed within a span of 24 h and 48–72 h, respectively. However, parasitoid emergence from fruit fly hosts exposed sequentially to F. arsianus and D. kraussii suggest that D. kraussii females are able to discriminate hosts already parasitized by F. arisanus. Results show that the co-evolutionary relationship between B. tryoni and D. kraussii does not help overcome the early-acting advantage of the egg parasitoid F. arisanus. Though F. arisanus may not have completely displaced D. kraussii in its native habitat, simultaneous inundative releases of these two parasitoid species (currently under consideration) might not help increase B. tryoni parasitism levels.

Population dynamics, native parasitoids and incidence of Tephritidae (Insecta, Diptera) in cherimoya (Annona cherimola mill.) secondary forests at Southern Ecuador

Cherimoya is native to southern Ecuador, where it occurs in secondary forests with a high pest incidence, mainly fruit flies. In this research, five McPhail traps baited with Süsbin® 10% were installed in four cherimoya forest, from December 2017 to April 2018, and fruits were collected during the fruition phase to extract the larvae. A total of 1083 Tephritidae individuals and 3613 pupae were obtained from traps and fruits, respectively. Nine species of Anastrepha, one species of Toxotrypana and two parasitoid species were identified. The most abundant species in traps and the only one obtained from fruits was A. fraterculus.

Proximity to host plant of a congener determines parasitism of a waterhyacinth biological control agent by a native parasitoid

The biological control agent Megamelus scutellaris Berg (Hemiptera: Delphacidae) was released in Florida in 2010 to improve control of the invasive aquatic plant, Pontederia (Eichhornia) crassipes (Mart.) Solms (Commelinales: Pontederiaceae). A native egg parasitoid, Kalopolynema ema (Schauff and Grissell) (Hymenoptera: Mymaridae), was documented utilizing M. scutellaris, potentially limiting its effectiveness as a biological control agent. An experiment to determine if the distance from K. ema’s native host impacted parasitism rate of M. scutellaris was conducted in artificial ponds with naturally occurring populations of the native insect species. Models indicated that parasitism decreased with distance from the native host and with increasing M. scutellaris density. Although parasitism increased with K. ema density, rainfall, and temperature, parasitism was low with over half of the test plants indicating no signs of parasitism on M. scutellaris. The lack of a density dependent response by K. ema suggests it will not interfere with biological control of P. crassipes in Florida.

Sugar feeding by parasitoids inside and around vineyards varies with season and weed management practice

Feeding on sugar-rich resources dramatically prolongs lifespan and increases foraging performance in most parasitoids. The physiological and fitness effects of sugar feeding were studied in many parasitoid species under lab conditions, but far fewer studies examined them in the field. Even less is known about the environmental conditions that affect the prevalence of sugar feeding in natural parasitoid communities. Such information can guide planning of suitable habitats for these important biological control agents. We compared sugar feeding frequencies in parasitoid communities along four seasons, in wine-producing vineyards and in nearby natural plots, using qualitative anthrone tests. We also tested how the vineyards’ weed management practice (mechanical trimming or herbicide application) affected the parasitoids’ sugar feeding rates. Sugar feeding was significantly more common in the natural areas compared to the vineyards in all seasons. Sugar feeding rates were highest during spring and lowest in the winter. They were not consistently affected by weed management treatment, but increased with the number of flowering plant species, especially in spring. Our results suggest that parasitoids are limited by sugar sources in agricultural plots even when undisturbed by farming activities (during winter in our case), and that 'softer' weed management treatments do not necessarily improve their prospects for sugar feeding. A more targeted approach, of planting or preserving a higher richness of flowering plants throughout the seasons, may provide parasitoids with more sugar sources and thus support them in agricultural plots.

Targeting diamondback moths in greenhouses by attracting specific native parasitoids with herbivory-induced plant volatiles.

We investigated the recruitment of specific parasitoids using a specific blend of synthetic herbivory-induced plant volatiles (HIPVs) as a novel method of pest control in greenhouses. In the Miyama rural area in Kyoto, Japan, diamondback moth (DBM) (Plutella xylostella, Lepidoptera: Plutellidae) larvae are an important pest of cruciferous crops in greenhouses, and Cotesia vestalis (Hymenoptera: Braconidae), a larval parasitoid of DBM, is found in the surrounding areas. Dispensers of HIPVs that attracted C. vestalis and honey feeders were set inside greenhouses (treated greenhouses). The monthly incidence of DBMs in the treated greenhouses was significantly lower than that in the untreated greenhouses over a 2-year period. The monthly incidences of C. vestalis and DBMs were not significantly different in the untreated greenhouses, whereas monthly C. vestalis incidence was significantly higher than monthly DBM incidence in the treated greenhouses. Poisson regression analyses showed that, in both years, a significantly higher number of C. vestalis was recorded in the treated greenhouses than in the untreated greenhouses when the number of DBM adults increased. We concluded that DBMs were suppressed more effectively by C. vestalis in the treated greenhouses than in the untreated greenhouses.

Non-target effects of the exotic generalist parasitoid wasp Fopius arisanus (Sonan) estimated via competition assays against Doryctobracon areolatus (Szepligeti) on both native and exotic fruit fly hosts

Biological control by the generalist egg parasitoid Fopius arisanus (Sonan) (Hymenoptera: Braconidae) has been proposed against Bactrocera carambolae (Drew & Hancock) (Diptera: Tephritidae) in northern Brazil. This study assessed possible effects of F. arisanus on native parasitoids by focusing on competition with the native wasp Doryctobracon areolatus (Szepligeti) (Hymenoptera: Braconidae) on two hosts, Anastrepha fraterculus (Wiedemann), a native tephritid, and Ceratitis capitata (Wiedemann), an introduced pest tephritid. Laboratory and greenhouse cage studies showed that F. arisanus parasitized < 3% of the native host in competition or alone compared to 41–65% for C. capitata, while D. areolatus parasitized 12–42% of the native host and < 4% on C. capitata. The host origin of F. arisanus did not affect subsequent parasitism rates on native or exotic hosts. However, when reared on C. capitata, F. arisanus had higher parasitism on C. capitata than on A. fraterculus. Lab and greenhouse competition studies showed that F. arisanus had no measurable detrimental effect on the native parasitoid in either the native or introduced host, suggesting that F. arisanus interfered minimally with the native parasitoid. Based on these results and other relevant studies showing non-preference of F. arisanus for the native fruit fly species, as well as the non-preference of native parasitoids for exotic fruit flies, we infer that the release of F. arisanus against exotic tephritids such as C. capitata and B. carambolae in Brazil would not cause major disruption of the native populations of A. fraterculus parasitoids.

Host suitability of Trichoplusia ni and Chrysodeixis chalcites (Lepidoptera: Noctuidae) for native and nonnative parasitoids expanding their host range

AbstractWe evaluated the host suitability and related traits of Trichoplusia ni Hübner (Lepidoptera: Noctuidae) and Chrysodeixis chalcites Esper (Lepidoptera: Noctuidae), which is nonnative in North America, for the native parasitoids Campoletis sonorensis Cameron (Hymenoptera: Ichneumonidae) and Copidosoma floridanum Ashmead (Hymenoptera: Encyrtidae), and the nonnative parasitoid Cotesia vanessae Reinhard (Hymenoptera: Braconidae). For the larval parasitoid C. sonorensis and C. vanessae trials, three-day-old larvae of both hosts were used, whereas one-day-old eggs of both hosts were used for the egg–larval parasitoid C. floridanum trial. For suitability parameters on each host exposed separately to each of the three parasitoid species, we measured parasitoid emergence (parasitoid success), parasitoids that did not emerge (parasitoid cocoon mortality), the proportion of male offspring (parasitoid sex ratio), hosts that developed into moths (host success), hosts that died without developing into moths or producing a parasitoid (host mortality), parasitoids emerging from cocoon masses (brood size), and the developmental times of parasitoids and hosts. For C. sonorensis, the native host and the nonnative host were found to be similarly suitable. For C. vanessae, the native host was more suitable than the nonnative host. For C. floridanum, the native host was suitable, whereas the nonnative host was not; however, sublethal effects on both the native and nonnative hosts were observed. The differential suitability of the hosts observed in this study contributes to the understanding of this measure as a dynamic factor in the expansion of parasitoids into novel host species.

Natural parasitism on Anastrepha spp. (Diptera: Tephritidae) over Neotropical region boundaries in northeastern Mexico

ABSTRACT Anastrepha is one of the most species rich-genera of fruit flies in the order Diptera involving pest species of quarantine importance to Mexico. This study aimed to explore and analyze the natural parasitism associated with Anastrepha spp. in a Neotropical transition region from Mexico in the biosphere reserve ‘El Cielo,’ Tamaulipas, Mexico. Anastrepha was represented by Anastrepha fraterculus (Wiedemann), A. ludens Loew, A. obliqua Macquart, and A. zuelaniae. Doryctobracon areolatus (Szépligeti) revealed the highest parasitism rate (77.3%), followed by Trichopria sp. Ashmead (63.6%), Odontosema anastrephae (Borgmeier) (29.5%), Utetes anastrephae Viereck (7.95%), Doryctobracon crawfordi (Viereck) (7.69%), Aganaspis sp. Lin (1.2%)., and Trybliographa nordlanderi (Wharton) (0.7%). Prunus persica and Spondias mombin hosted the highest diversity of parasitoids. Natural parasitism of Do. crawfordi on A. ludens in Citrus sinensis is reported. Trichopria sp. was recorded attacking Anastrepha zuelaniae Stone in Passiflora serratifolia and O. anastrephae parasitising A. fraterculus and A. ludens on P. persica. Results highlight the prevalence of native parasitoids, as well as the biosphere reserve ‘El Cielo’ as the most northern natural reservoir of natural enemies of Anastrepha pest species in the neotropical region.

Interactions between Two Parasitoids of Tephritidae: Diachasmimorpha longicaudata (Ashmead) and Psyttalia cosyrae (Wilkinson) (Hymenoptera: Braconidae), under Laboratory Conditions.

Simple SummaryWasps, generally referred to as “farmers friends” because of their ability to control devastating fruit flies, were imported from Hawaii and released in Kenya for the management of the invasive Oriental fruit fly Bactrocera dorsalis. It was noted that the introduced wasp had developed a liking for the native fruit fly species Ceratitis cosyra which already has a native wasp controlling it. We therefore undertook a study to understand the interaction of the introduced and native wasp on the invader Oriental and native fruit flies. Our results show that when the native wasp attacks the invader fruit fly, the wasp is killed because of the strong immune system of the oriental fruit fly. The good news is that the introduced wasp efficiently controls both the invader and the native fruit flies. We have discussed these findings based on various scientific principles which favor the co-existence of the two wasps without any detrimental effect on their survival. We have also suggested that more studies be conducted in open field conditions where both fruit flies occur in abundance and choices regarding which fruit fly species to attack are much wider.The braconid wasp, Diachasmimorpha longicaudata (Ashmead), was introduced in Kenya from Hawaii for classical biological control of the invasive tephritid, Bactrocera dorsalis Hendel. Following reports that D. longicaudata had formed new associations with Ceratitis cosyra, laboratory experiments were conducted to assess the interaction between the introduced and the native parasitoid of C. cosyra; Psyttalia cosyrae (Wilkinson) under three scenarios: B. dorsalis only, C. cosyra only and mixed populations of the two species. Parasitoids were introduced to the host as sole, sequential and simultaneous releases. Host searching and probing events were five times higher for D. longicaudata than P. cosyrae with both hosts. Total parasitism was highest (78%) when D. longicaudata was released alone on C. cosyra, compared to 20% for P. cosyrae released on the same host. Releases of P. cosyrae on B. dorsalis resulted in 0% parasitism, compared to 64% parasitism by D. longicaudata. Specific parasitism for P. cosyrae was three times higher when P. cosyrae was released first in sequential releases on C. cosyra compared to when it was released after D. longicaudata. These findings suggest that the two parasitoids can both suppress C. cosyra but B. dorsalis acts as a reproductive sink for P. cosyrae. Our findings should form the basis of field investigations where options are much wider for both parasitoids.

Biological control of invasive stink bugs: review of global state and future prospects

AbstractInvasive stink bugs (Hemiptera: Pentatomidae) are responsible for high economic losses to agriculture on a global scale. The most important species, dating from recent to old invasions, include Bagrada hilaris (Burmeister), Halyomorpha halys (Stål), Piezodorus guildinii (Westwood), Nezara viridula (L.), and Murgantia histrionica (Hahn). Bagrada hilaris, H. halys, and N. viridula are now almost globally distributed. Biological control of these pests faces a complex set of challenges that must be addressed to maintain pest populations below the economic injury level. Several case studies of classical and conservation biological control of invasive stink bugs are reported here. The most common parasitoids in their geographical area of origin are egg parasitoids (Hymenoptera: Scelionidae, Encyrtidae, and Eupelmidae). Additionally, native parasitoids of adult stink bugs (Diptera: Tachinidae) have in some cases adapted to the novel hosts in the invaded area and native predators are known to prey on the various instars. Improving the efficacy of biocontrol agents is possible through conservation biological control techniques and exploitation of their chemical ecology. Moreover, integration of biological control with other techniques, such as behavioural manipulation of adult stink bugs and plant resistance, may be a sustainable pest control method within organic farming and integrated pest management programs. However, additional field studies are needed to verify the efficacy of these novel methods and transfer them from research to application.

Field collection of egg parasitoids of Pentatomidae and Scutelleridae in Northwest Italy and their efficacy in parasitizing Halyomorpha halys under laboratory conditions

AbstractThe invasion of Halyomorpha halys (Stål) (Hemiptera: Pentatomidae) has caused severe economic damage in crops in North America and Europe, motivating research to identify its natural enemies, both in native and invaded areas. In its Asian native range, the main natural enemies are egg parasitoids, among which the most effective are Trissolcus japonicus (Ashmead) and Trissolcus mitsukurii (Ashmead) (Hymenoptera: Scelionidae) in China and Japan, respectively. In Europe, biology, host range, and impact of most native scelionid species are not well‐known. The present study aimed to investigate (1) presence and abundance of scelionid species that parasitize native Pentatomidae and Scutelleridae eggs in Northwest Italy, and (2) their ability to develop on H. halys eggs. During 4‐year field surveys, egg masses were collected and reared until bug nymph or adult parasitoid emergence. Then, the obtained scelionid females were tested for their ability to parasitize H. halys eggs in laboratory no‐choice experiments. Egg masses of all collected bug species were parasitized, and Telenomus spp. (Hymenoptera: Scelionidae), Trissolcus belenus (Walker), and Anastatus bifasciatus (Geoffroy) (Hymenoptera: Eupelmidae) were the most common parasitoids. In the laboratory, Trissolcus kozlovi Rjachovskij was the only species to significantly produce offspring from fresh H. halys eggs, whereas all tested Trissolcus species significantly induced host egg abortion (non‐reproductive effects). This study provides knowledge of the parasitoid species associated with native bugs, and represents a starting point to investigate the intricate interactions between native and exotic parasitoids recently found in northern Italy. These egg parasitoids could potentially be effective biocontrol agents of H. halys.

First Report of Native Parasitoids of Fall Armyworm Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) in Mozambique.

Simple SummaryIn 2016, a highly destructive insect pest with origin in the Americas was detected in Africa. The pest is known to feed primarily on maize which is a staple food in the continent. Since then, farmers have been using chemical insecticides to control the pest. Chemical insecticides are expensive and harmful to the environment. In this article, the authors Albasini Caniço, António Mexia, and Luisa Santos discuss the possibility of application of an alternative method of control known to be environmentally friendly and economically sustainable in the long term. The method, known as “biological control”, can be easily implemented by farmers, and has the potential to reduce the population of the insect pest and production costs, and bring long term benefits to the environment.The alien invasive insect pest Spodoptera frugiperda Smith (Lepidoptera: Noctuidae), commonly referred to as fall armyworm (FAW), is causing significant losses to maize production in Africa since its detection in 2016. As an emergency response, governments in several countries distributed and/or promoted massive use of synthetic insecticides among smallholder farmers to fight FAW. The inappropriate use of synthetic insecticides by non-trained and ill-equipped farmers raises environmental and health concerns. This study aimed to assess the occurrence of native parasitoids of FAW, their parasitism rates, and relative abundance in the central province of Manica, Mozambique. A field collection of FAW egg masses and larvae was conducted from May to August 2019 (dry season of the 2018/2019 cropping season) and in December 2019 and January 2020 (rainy season of 2019/2020 cropping season). A total of 101 egg masses and 1444 larvae of FAW were collected from infested fields. Five larval parasitoids were recorded, but no egg parasitism was observed. Coccygidium luteum Brullé (Hymenoptera: Braconidae) and Drino quadrizonula Thomson (Diptera: Tachinidae) were the primary parasitoids. Maximum parasitism of 23.68% and 8.86% and relative abundance of 100 and 96.3 were recorded for C. luteum and D. quadrizonula, respectively. Total parasitism by different parasitoid species was at 9.49%. Cultural practices favoring the action of these parasitoids should be advocated.

Characterization of native parasitoid community associated with the invasive pest Dryocosmus kuriphilus (Hymenoptera: Cynipidae) in Cantabria (northern Spain)

ABSTRACT A survey of the native parasitoid community was conducted to characterize its possible use as biological control for Asian Chestnut Gall Wasp (ACGW) at two sampling sites in northern Spain. To this end, 500 ACGW galls were collected over five sampling dates between May and July 2017; 250 of them were dissected to estimate the parasitism rates and the remaining 250 galls were placed in emerging rearing boxes to collect adult parasitoids. Seven native parasitoid species belonging to six families (i.e. Eupelmidae, Eurytomidae, Ormyridae, Megastigmidae, Pteromalidae and Torymidae) were identified by morphological traits. All sampled species are considered as native parasitoids of gallers-oaks (Quercus spp.). The most abundant species were Sycophila variegata (Curtis), Torymus auratus (Müller) and Sycophila biguttata (Swederus), representing 70% of the identified parasitoids. In addition, the presence of these native parasitoids was associated with high parasitism rates, especially at the site that was surrounded by oak trees. Our findings highlight the important contribution of native parasitoids to pest regulation throughout the period of ACGW gall development.