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Intraspecific competition and avoidance of superparasitism are critical for biological control. In this study, we conducted behavioural and biological trials to assess intraspecific competition in the egg parasitoid Anagrus virlai, targeting the corn leafhopper Dalbulus maidis. Firstly, we investigated whether A. virlai can distinguish between unparasitized and parasitized host eggs using long‐range cues in an olfactometer experiment. Secondly, we evaluated whether A. virlai parasitism and emergence under varying host densities are affected by the presence of multiple conspecific wasps foraging within the same host patch. In the olfactometer test, A. virlai did not differentiate between corn leaves with parasitized and unparasitized eggs. Regarding the parasitoid's performance, the number and percentage of parasitized eggs were influenced by the density of females foraging simultaneously in the same host patch. Significant increases in collective parasitism were observed when two or more parasitoids were present in each arena. Competitive interaction did not affect wasp emergence, and A. virlai proved to be a solitary species. Moreover, the negative relationship between per‐capita parasitism and the number of conspecific wasps per arena demonstrated mutual interference among parasitoids. These findings highlight the impact of competitive interactions on A. virlai performance and suggest a potential aggregated response of the parasitoid to high‐density patches of hosts. [ABSTRACT FROM AUTHOR]

Host specificity is a key criterion for the implementation of any biological control program. In parasitoid wasps, host specificity is mediated by their response to chemical cues directly and indirectly associated with their hosts during foraging. Although intraspecific variation in foraging behaviour is documented, it is rarely integrated into risk assessment studies of potential biological control agents, as is the case for Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae), an Asian egg parasitoid and biological control agent of the invasive Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). In the present study, we compared the behavioural response of T. japonicus females of an adventive line present in Switzerland and an Asian line (Beijing USDA), recently mass released in Italy, to cues of its target host H. halys and non-target host Pentatoma rufipes (L.) (Hemiptera: Pentatomidae). We observed minimal differences in host acceptance, exploitation and suitability in no-choice tests. In contrast, the behavioural response to host contact kairomones left on leaf substrates significantly differed between the two lines. While both lines preferred chemical footprints of H. halys in comparison to P. rufipes, females of the Beijing USDA line responded more strongly to host kairomones. The observed intraspecific variation in behavioural traits highlights the relevance of considering genetically distinct parasitoid lines and their host foraging behaviour in biological risk assessment studies. However, the implications of intraspecific variation in parasitoid foraging behaviour for biological control of a pest and non-target effects in the field remain challenging to predict. [ABSTRACT FROM AUTHOR]

Egg parasitoids of the family Scelionidae are important biological control agents in many agricultural systems, including rice. Several species attack Pentatomidae. Some are used in applied biological control programs. We studied the richness, abundance, and population fluctuations of scelionids through gradients of distance from the forest near the cultivated areas and in two stages of plant development under different rice managements. The work took place in two irrigated rice crops, one with organic management (O.M.) and another with conventional management (C.M.), in the municipality of Nova Santa Rita, Rio Grande do Sul, Brazil, during the 2013/2014 and 2014/2015 seasons. The parasitoids were collected with Malaise traps placed at different distances in relation to the riparian forest surrounding the rice crop. Specimens were collected twice a month from seeding until the rice harvest. The most abundant genera were Idris, Telenomus, and Baeus. Telenomus podisi, Telenomus sp. 3, Telenomus sp. 2, and Telenomus sp. 1, were the most abundant morphospecies, and their abundance changed over the plant stages and seasons. The rice phenological stage influenced the diversity over the two seasons and, in the second one, the kind of pesticide used possibly had a negative influence on the parasitoid assemblage in conventional management. Close to the forest, there was a greater abundance of Scelionidae in the C.M. area in the first season. This was not found in the O.M. area at any crop season. The high abundance of scelionids indicates that natural biological control may be important in the rice crop, particularly in areas under organic management. [ABSTRACT FROM AUTHOR]

Stink bug egg parasitoids (Scelionidae) use several host and non-host chemical and physical cues to find suitable hosts. These cues can interact in the field producing multimodal stimuli, which can be manipulated to increase parasitoid attraction and biological control of stink bugs in conservation biological control strategies. We aimed to investigate how multimodal chemical and physical stimuli affect stink bug egg parasitoid recruitment and parasitism in soybean crops. We performed a field experiment where semiochemicals and visual stimuli were presented alone or in combination during three soybean growing seasons. We evaluated the occurrence of stink bug parasitoids and parasitism rates using sentinel eggs, and stink bug species abundance. Long-distance semiochemicals (herbivore-induced plant volatiles and sex pheromone) did not interfere on Scelionidae parasitoid recruitment. Visual stimuli and stimuli combinations negatively interfered on parasitoid recruitment or had no effect. The parasitism of sentinel eggs varied among seasons, and long-distance semiochemicals increased parasitism on one season. In the other seasons there was a significant effect of predation on the sentinel stink bugs eggs. Predation, mostly by ants, was the main egg mortality factor, which could have masked parasitism effects. The stink bug Euschistus heros (Hemiptera: Pentatomidae) was always the most abundant species occurring with other seven species. Our results indicate the relevance of different biological control agents on stink bug egg mortality. We discuss the applications and major flaws for conservation biological control of stink bugs and its compatibility with augmentative releases of egg parasitoids, especially for Telenomus podisi. [ABSTRACT FROM AUTHOR]

Trissolcuss grandis Thomson, is an important egg parasitoid of Eurygaster integriceps Puton that can control its population in wheat and barley fields. Despite valuable results from previous studies, the thermal development of T. grandis over a wide range of temperatures had not been elucidated completely. This study was conducted to evaluate the thermal effect on the development of T. grandis using Sunn pest eggs as hosts in a wide range of temperatures (12.5 to 40 ±0.5℃, 65 ± 5% RH., and a photoperiod of 16L:8D h) in the laboratory condition. The development times of the immature stage (Egg-Adult) of T. grandis decreased with increasing temperatures up to 35 ºC for both sexes. Patterns of temperature-dependent development times of the immature stage of females and males (i.e. emergence of females and males of T. grandis adults) were modeled and simulated with linear and nonlinear regression analyses. The estimated low-threshold temperatures (Tb) were 10.61 and 10.62 ºC for females and males, respectively. Thermal constants (k) of the immature stage of females and males were 179.85 and 161.03 degree-days (DD), respectively. Stage transition models for females and males adults of T. grandis were constructed using two basic components of nonlinear development rate (modified Sharpe & DeMichele model function) and distribution models (two-parameter Weibull function) to simulate the proportion of individuals shifted from egg to adult. These models will be useful in building a T. grandis population model that will describe its seasonal occurrence pattern and population dynamics under various wheat and barley fields and optimize environmental conditions in mass rearing.

Myartsevaia chrysopae (Chalcidoidea: Encyrtidae) (Crawford 1913), and Telenomus lobatusJohnson and Bin 1982, and Telenomus tridentatusJohnson and Bin 1982 (Platygastroidea: Scelionidae) were reported for the first time in Yautepec, Morelos, Mexico. These parasitoids emerged from the eggs of Chrysopidae (Neuroptera) that had been collected from maize and lemon leaves. Resumen. Se registran por primera vez a Myartsevaia chrysopae (Crawford 1913) (Chalcidoidea: Encyrtidae), Telenomus lobatusJohnson and Bin 1982, y T. tridentatusJohnson and Bin 1982 (Platygastroidea: Scelionidae) en Yautepec, Morelos, parasitoides de huevos de Chrysopidae (Neuroptera), recolectados de hojas de maíz y limón. [ABSTRACT FROM AUTHOR]

The European pepper moth (Duponchelia fovealis) is predominant in the main strawberry production areas, including Brazil, as an important invasive pest and causes substantial damage to the crop. This damage is mainly attributed to the lack of effective management strategies. A promising alternative for managing this pest is implementing biological control through releasing natural enemies. This study determined the dispersal capacity of Trichogramma pretiosum for the management of D. fovealis in a strawberry crop in a low tunnel system 24, 48, and 72 h after parasitoid release. The experiments were carried out on strawberry farms in the mountainous region of Espírito Santo. Tunnels measuring 1.20 m wide by 50 m long were selected, in which artificial infestations of 30, 60, 90, and 120 eggs of D. fovealis were made on both sides of the strawberry tunnel at distances of 3, 7, 11, and 15 m, respectively, from the central point where the parasitoids were released. After the initial 24 h, new eggs were placed to replace the infested ones; the replacement was repeated at 48 and 72 h. The results indicated that, in strawberry plantations, T. pretiosum was efficient in parasitism. There was no difference between parasitism 24 and 48 h after parasitoid release, but parasitism was substantially lower after 72 h. The dispersion capacity of T. pretiosum was 14.21 linear meters, corresponding to an area of 17.05 m2. It is recommended that 93,000 T. pretiosum females be released per hectare every three days. [ABSTRACT FROM AUTHOR]

Simple Summary: Laboratory and field observations were used to evaluate the compatibility of yellow sticky cards with augmentative releases of T. dendrolimi for control of orchard pests, particularly C. sasakii and G. molesta. Female T. dendrolimi showed stronger attraction to yellow and white than to red, green or blue. Yellow sticky cards trapped significant numbers of T. dendrolimi in the field, reducing biological control of C. sasakii as well as the number of lacewings naturally recruited to the orchard. Judicious use of yellow sticky cards in orchards is therefore recommended to avoid disruption of biological control, specifically removing them in May before peak flights of moth pests require releases of egg parasitoids. Integrated pest management relies upon mutual compatibility among pest control tactics. The fruit-boring moths Carposina sasakii and Grapholita molesta can be devastating pests of pome and stone fruit production. Trichogramma dendrolimi parasitizes the eggs of these pests, preventing their eclosion, but its efficacy can be reduced by other pest control tactics. We tested T. dendrolimi attraction to five colors, and moth attraction to six colors, in laboratory choice tests, and thereafter deployed yellow sticky cards in tandem with releases of T. dendrolimi in field trials in a pear orchard. Yellow sticky cards deployed at high density trapped T. dendrolimi and reduced their numbers post-release. They also trapped adult G. molesta, which appeared to compensate for reduced egg parasitism on this species, but not on C. sasakii, which had higher abundance in plots with yellow sticky cards. The cards also captured adult lacewings, likely reducing their numbers in the field, but did not capture large numbers of lady beetles. The results suggest that yellow sticky cards can be used at high density to control aphids, psyllids and leafhoppers in early spring (March and April) when natural enemies are in low numbers, then removed in May so as not to interfere with augmentative releases of T. dendrolimi that must be timed to coincide with peak flights of fruit-boring moths. This strategy should enhance the compatibility of yellow sticky cards with egg parasitoid releases. [ABSTRACT FROM AUTHOR]

The fairyfly Cosmocomoidea tenuis Xu, Lin and Hu (Hymenoptera: Mymaridae), which was previously known only from mainland China (Fujian) and Taiwan, is for the first time recorded from Japan where it was reared from organic kiwifruit, Actinidia chinensis and A. deliciosa (Actinidiaceae), leaves in Yamanashi Prefecture on Honshu Island. Both sexes of C. tenuis are redescribed and illustrated based on specimens from Japan. Its apparent host association with black-tipped leafhopper Bothrogonia ferruginea (Fabricius) (Hemiptera: Cicadellidae: Cicadellinae) is discussed. This sharpshooter leafhopper is a common but minor pest in organic vineyards and kiwifruit orchards in Japan and a known vector of the phytopathogenic bacterium Xyllella fastidiosa on cultivated grapes in Taiwan. Egg parasitoids of B. ferruginea, a widespread species in parts of Asia, have been previously unknown. Cosmocomoidea tenuis is also identified as an egg parasitoid of another known vector of X. fastidiosa in Taiwan, a sharpshooter (Cicadellinae) leafhopper Kolla paulula (Walker). [ABSTRACT FROM AUTHOR]

Trissolcuss grandis Thomson, is an important egg parasitoid of Eurygaster integriceps Puton that can control its population in wheat and barley fields. Despite valuable results from previous studies, the thermal development of T. grandis over a wide range of temperatures had not been elucidated completely. This study was conducted to evaluate the thermal effect on the development of T. grandis using Sunn pest eggs as hosts in a wide range of temperatures (12.5 to 40 ±0.5ºC, 65 ± 5% RH., and a photoperiod of 16L:8D h) in the laboratory condition. The development times of the immature stage (Egg-Adult) of T. grandis decreased with increasing temperatures up to 35 ºC for both sexes. Patterns of temperature-dependent development times of the immature stage of females and males (i.e. emergence of females and males of T. grandis adults) were modeled and simulated with linear and nonlinear regression analyses. The estimated low-threshold temperatures (Tb) were 10.61 and 10.62 ºC for females and males, respectively. Thermal constants (k) of the immature stage of females and males were 179.85 and 161.03 degree-days (DD), respectively. Stage transition models for females and males adults of T. grandis were constructed using two basic components of nonlinear development rate (modified Sharpe & DeMichele model function) and distribution models (two-parameter Weibull function) to simulate the proportion of individuals shifted from egg to adult. These models will be useful in building a T. grandis population model that will describe its seasonal occurrence pattern and population dynamics under various wheat and barley fields and optimize environmental conditions in mass rearing. [ABSTRACT FROM AUTHOR]

The release of Telenomus podisi in the pupae stage for the control of Euschistus heros can be negatively affected by biotic and abiotic causes of mortality, reducing parasitoid emergence from pupae in the field. Therefore, this work aimed to develop a solid diet for adults of T. podisi that can be used inside capsules to enable the release of fed and copulated adults. Among different tested diets, 100 % honey, offered as honey-macerated cotton strings, obtained the best results. This solid honey diet is the most appropriate to feed T. podisi inside release capsules, enabling the release of fed adults and, thereby, reducing parasitoid mortality. In addition, the solid diet inside capsules ensures that parasitoids can be stored for at the least 15 days after the onset of adult emergence before their release in the field. This makes the release process more flexible and attractive to farmers by enabling a release delay in bad weather conditions or for other reasons.

The codling moth, Cydia pomonella L. (Lepidoptera: Tortricidae), is a key pest of apples in Tunisia and other countries around the world. Various management strategies have been applied to manage this pest including releases of parasitoids. Trichogramma wasps are known as efficient biocontrol agents tested against a large number of lepidopteran pests including C. pomonella. Two inundative releases of Trichogramma cacoeciae Marchal, at the rates of 25 000 and 50 000 parasitoids per ha, were performed when threshold was reached (2 to 3 adults per pheromone trap) in a commercial apple orchard, in 2018. Results indicated the occurrence of three flight peaks registered in the spring, summer and autumn of the growing season. The efficacy of the two release rates in reducing the infestation level of the population of the codling moth was proved herein. Average infestation level of fruits was significantly reduced after of the first release with reduction of about 27% for rate 1 and 22% for rate 2 compared to the untreated control (45%). Likewise, the average percentage of damaged apples was significantly reduced after the second release (23, 18.37 and 43.37 % respectively for the rate 1, rate 2 and the untreated control). The results showed the efficacy of T. cacoeciae parasitoids as efficient candidates to control C. pomonella.

Abstract Telenomus remus (Hymenoptera: Scelionidae) is an efficient parasitoid of Spodoptera eggs. However, biological control programs require taxonomic, bioecological and behavioral studies of biological agents. Although the performance of T. remus in pest control has been evaluated, little is known about its behavioral aspects that can influence IPM tactics. The aim of this study was therefore to study the parameters related to the oviposition behavior of T. remus on Spodoptera frugiperda (Lepidoptera: Noctuidae) eggs. The experiment was conducted in the laboratory, where 17 females were transferred individually to arenas containing a mass of S. frugiperda eggs. Oviposition behavior was recorded for 30 minutes. The average walking speed of the females was 0.116 mm.s-1 and the total distance covered was 203.3 mm. The females remained on the egg masses for an average of 16.7 min, which corresponds to more than half of the total time. The average number of parasitized eggs was 15.1 per female in 30 minutes. Females with larger antennae had lower values for average speed and total distance covered. The results of the parameters evaluated show the standard oviposition behavior of T. remus females on S. frugiperda eggs and help us to better understand the species.

Abstract Background The fall armyworm (FAW) Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is a newly introduced pest that damages maize production in Indonesia. To control this pest in maize fields, better solution is to use the egg parasitoid, such as Telenomus remus Nixon (Hymenoptera: Scelionidae), as another better option to apply topically entomopathogenic fungi (EPF). Therefore, it is necessary to study the effect of the EPF on the egg parasitoid of T. remus. The objective of this research was to evaluate susceptibility of immature T. remus to the EPFs, Beauveria bassiana, Chaetomium sp., Curvularia lunata, Penicillium citrinum, and Metarhizium anisopliae. The EPFs (1 × 106 conidia mL−1) were sprayed topically on one-day-old mummies (immature T. remus) in post-parasitism periods. Results The results showed that the cumulative percentage of T. remus adult emergence from the mummies treated with EPF on 11 days after treatment ranged 54–100% and was non-significantly different than those of control (untreated with EPF) (90.48%). Therefore, the immature stage of T. remus was not susceptible to the EPF topical application. The EPFs were harmless to the immature stage of T. remus. Percentage of aborted mummies (embryonic death) of T. remus after treated with the EPF was also non-significantly different than those of control. However, the EPFs could significantly affect developmental times of immatures stages of T. remus. The EPF also could shorten the adult longevity of the egg parasitoid. Conclusions The immature T. remus is less sensitive to the EPFs; B. bassiana, Chaetomium sp., C. lunata, P. citrinum, and M. anisopliae. It can be considered integrating the EPF with T. remus inundation in maize field. However, it is necessary to limit the topical application of the EPF to avoid negative effects on the adult longevity of the egg parasitoid. Thus, it needed to be further investigated that the application of the endophytic EPFs by inoculating the fungi within the plant tissue could be harmless to the egg parasitoids.

The rice stem borer, Chilo suppressalis Walker (Lepidoptera: Crambidae), is a key rice pest, causing major yield loss in Asia. Trichogramma japonicum Ashmead (egg parasitoid) and Beauveria bassiana Balsamo Vuillemin (entomopathogenic fungi) are two important organisms used in sequence or integrated for C. suppressalis management. However, few information is available on potential antagonism between the two biocontrol agents. Under laboratory conditions, we assessed whether the presence of B. bassiana had an impact on the oviposition preference of T. japonicum for C. suppressalis eggs. We characterized parasitic behavior of T. japonicum exposed or not to B. bassiana on C. suppressalis eggs (varying in age) by carrying out observation experiments and using a Y-tube olfactometer. We also evaluated the response of T. japonicum to B. bassiana-affected vs. -unaffected C. suppressalis eggs. Olfactometer tests showed that T. japonicum-vectored B. bassiana and/or C. suppressalis eggs immersed in B. bassiana did not have major effects on choices made by the parasitoid. T. japonicum attacked C. suppressalis eggs of 0-d, 2-d and 4-d old and had preference to fresh host eggs (0-d). However, the contaminated T. japonicum were not able to distinguish between eggs of 0-d old and 4-d old in contrast with the uncontaminated parasitoids. A reduction in insect locomotion (no-response number) of T. japonicum contaminated by B. bassiana preferring to 4-d-old host eggs was found, which was compared to the no-response number of uncontaminated T. japonicum preferring to 0-d-old host eggs. The parasitic behavior of host searching time, checking time, drilling and oviposition time and the parasitism rate (in 24 h) did not differ between the fresh eggs immersed with B. bassiana and control (eggs without B. bassiana). On the other hand, searching and checking times were slightly higher when parasitoids were contaminated by B. bassiana (drilling and oviposition times as well as the parasitism rate in 24 h were not impacted). Therefore, T. japonicum may be used together with B. bassiana in integrated program targeting C. suppressalis. [ABSTRACT FROM AUTHOR]

In its native range, Trissolcus japonicus (Ashmead) (Hymenoptera: Scelionidae) is a main egg parasitoid of Halyomorpha halys (Stål) (Hemiptera; Pentatomidae). Adventive populations of this parasitoid have been spreading in Europe and North America, allowing active distribution efforts in these areas to utilize it against H. halys in agriculture. We tested exposure of adults and parasitized egg masses to residues of a range of insecticides an adjuvant that the wasp could encounter in perennial horticultural crops, and how exposure might affect key behaviors. The insecticides included Burkholderia rinojensis, Methoxyfenozide, Sulfoxaflor, and Spinosad, and the adjuvant NuFilm®P. The lethal effects were investigated after exposure for 1, 6, and 24 hours to residues applied to Munger cells using a Potter spray tower to determine mortality levels. Sulfoxaflor and Spinosad resulted in 73% and 100% mortality after 24 hours at field rates, while Methoxyfenozide caused 19% mortality at the same rate. Little mortality occurred with Burkholderia rinojensis and NuFilm®P at recommended rates after 24 hours. Regarding sublethal effects, Spinosad, Sulfoxaflor, and Burkholderia rinojensis negatively impacted reproduction. Sulfoxaflor caused a lower angular velocity in parasitoids exposed to H. halys traces. Spinosad, Methoxyfenozide, and NuFilm®P induced a significantly lower overall circadian activity. Our results showed that precision timing of insecticide sprays to pests is necessary, especially for biocontrol programs that involve the release of parasitoids such as T. japonicus. Our results also illustrate how sensor data acquisition and behavioral analysis software can be utilized to detect important sublethal effects such as circadian disruption in minute parasitoids. [ABSTRACT FROM AUTHOR]

Trichogramma, a genus of egg parasitoid wasps, are widely used as biological control agents and serve as model organisms in parasitoid research. Despite their significance, the understanding of RNA interference (RNAi) in Trichogramma remains very limited. We identified RNAi-associated genes by bioinformatic approaches and experimentally assessed the feasibility of gene knockdown via RNAi for gene functional studies, as well as the susceptibility of T. dendrolimi to envionmental RNAi (dsRNAs targeting 12 genes). We found that Trichogramma genomes contain a complete set of genes in the RNAi pathway and exhibit extensive gene expansion of dsRNase, which may influence RNAi efficiency by degrading dsRNA. We demonstrated successful RNAi through pupal microinjection in T. dendrolimi Matsumura, providing a technical approach for future gene functional studies. In addition, we observed no evidence of susceptibility to environmental RNAi in either T. dendrolimi adults or larvae. This low environmental RNAi sensitivity in Trichogramma could suggest a reduced risk of RNAi-based pest management strategies affecting nontarget Trichogramma populations. Overall, this study presents a technical approach for conducting gene functional studies in Trichogramma and provides a foundation for evaluating the nontarget effects of RNAi-based pest control strategies on Trichogramma. [ABSTRACT FROM AUTHOR]

Simple Summary: The inter-row management strategy in the vineyard influences the diversity of the vegetation and, consequently, the presence and activity of natural enemies of grapevine pests. This study aims to evaluate whether the replacement of periodical tillage with the alternate mowing of the resident herbaceous vegetation in vineyard inter-rows reduces the density of the European leafhoppers Hebata vitis and Zygina rhamni by improving the presence and activity of their natural enemies in the context of conservation biological control. The results show that, on grapevines with ground vegetation, the number of hunting spiders increases, thus reducing the leafhopper population with their predation activity. Green covering also improves hymenopteran parasitoids characterized for their important role in the grapevine pest control. A greater vegetation diversity in the vineyard improves the landscape quality of the agroecosystem and, by supporting the activity of the natural enemies of grapevine pests, reduces the need for insecticide applications in the vineyards. Inter-row management in vineyards can influence the abundance of grapevine pests and their natural enemies. In 2013–2015, in a vineyard in northeastern Italy, the influence of two vineyard inter-row management strategies (i.e., alternate mowing, AM, and periodical tillage, PT) on the population dynamics of grapevine leafhoppers Hebata vitis and Zygina rhamni and their natural enemies, the mymarid Anagrus atomus and spiders (Araneae), and other hymenopteran parasitoids, were studied with different survey approaches. The infestations of both leafhoppers were lower in AM than PT due to the reduced leafhopper oviposition and higher nymph mortality in AM. This occurred although leafhopper egg parasitization by A. atomus was greater in PT than AM according to a density-dependent relationship with the leafhopper egg amount. Hymenopteran parasitoids other than A. atomus were the most abundant in AM, probably due to the higher availability of nectar and pollen than in PM. The significantly higher population densities of hunting spiders in AM than PT can be associated with the higher predation of leafhopper nymphs. Therefore, the study demonstrated that the alternate mowing of vineyard inter-rows enhances the abundance of natural enemies, such as spiders and hymenopteran parasitoids, and can contribute to grapevine leafhopper pest control. [ABSTRACT FROM AUTHOR]

Background: The fall armyworm (FAW) Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is a newly introduced pest that damages maize production in Indonesia. To control this pest in maize fields, better solution is to use the egg parasitoid, such as Telenomus remus Nixon (Hymenoptera: Scelionidae), as another better option to apply topically entomopathogenic fungi (EPF). Therefore, it is necessary to study the effect of the EPF on the egg parasitoid of T. remus. The objective of this research was to evaluate susceptibility of immature T. remus to the EPFs, Beauveria bassiana, Chaetomium sp., Curvularia lunata, Penicillium citrinum, and Metarhizium anisopliae. The EPFs (1 × 106 conidia mL−1) were sprayed topically on one-day-old mummies (immature T. remus) in post-parasitism periods. Results: The results showed that the cumulative percentage of T. remus adult emergence from the mummies treated with EPF on 11 days after treatment ranged 54–100% and was non-significantly different than those of control (untreated with EPF) (90.48%). Therefore, the immature stage of T. remus was not susceptible to the EPF topical application. The EPFs were harmless to the immature stage of T. remus. Percentage of aborted mummies (embryonic death) of T. remus after treated with the EPF was also non-significantly different than those of control. However, the EPFs could significantly affect developmental times of immatures stages of T. remus. The EPF also could shorten the adult longevity of the egg parasitoid. Conclusions: The immature T. remus is less sensitive to the EPFs; B. bassiana, Chaetomium sp., C. lunata, P. citrinum, and M. anisopliae. It can be considered integrating the EPF with T. remus inundation in maize field. However, it is necessary to limit the topical application of the EPF to avoid negative effects on the adult longevity of the egg parasitoid. Thus, it needed to be further investigated that the application of the endophytic EPFs by inoculating the fungi within the plant tissue could be harmless to the egg parasitoids. [ABSTRACT FROM AUTHOR]

Combining biological and chemical control is essential for implementing Integrated Pest Management programs. In soybean crop, one way to integrate these control tactics for managing Lepidoptera pests, such as Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is by releasing parasitoids to control moth's eggs, and spray chemical pesticides to control caterpillars. However, it is necessary to know if these tactics can be combined, with no harm to their individual performances. Therefore, this study evaluated lethal and sublethal effects on Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) following exposure to nine insecticides commonly used in soybean. First, adults were exposed to insecticide residues on leaf disks immediately after spraying and acute toxicity was assayed 24 h after exposure. Surviving insects, as well as their progeny, were evaluated for sublethal effects, such as reduction in parasitism, longevity and flight capacity. In a second bioassay, leaf disks were cut from greenhouse-grown plants 3, 7, 10, 17, 24 and 31 days after insecticide application. Adults were again exposed to leaf disks for 24 h, and then allowed to parasitize host eggs for 24 h, and progeny survival to emergence was recorded. Chlorantraniliprole and indoxacarb were the safest pesticides, with low acute toxicity and no sublethal effects, and therefore can be considered compatible with releases of T. pretiosum. Methoxyfenozide, teflubenzuron and flubendiamide also lacked any acute toxicity, but reduced either female longevity, or the longevity of their offspring. Acephate and chlorpyriphos both caused >85% wasp mortality, whereas lambda-cyhalothrin + thiamethoxam and chlorfenapyr had the greatest residual activity, causing high mortality and many sublethal effects. Therefore, these products cannot be used associated with releases of the parasitoid in IPM programs. [ABSTRACT FROM AUTHOR]

The use of egg parasitoids in the biological control of insect pests is a promising technique in integrated pest management. However, there is little information on the effects of parasitoid female age and host egg age on parasitization rates specifically on the behaviour of the egg parasitoids such as Trichogramma pretiosum Riley and Telenomus remus Nixon which can have substantial effects on parasitism towards insect pest eggs. Thus, this communication evaluated the relationships between the age of the parasitoid and host egg on the parasitism of Spodoptera frugiperda eggs by T. pretiosum and T. remus in three independent bioassays. In the first and second bioassay, two egg parasitoids (T. pretiosum and T. remus) females were grouped by age in days (ranging from 1–6 and 1–10 days old for T. pretiosum and T. remus, respectively) and were offered 100 eggs of S. frugiperda per treatment for 24 h separately. In the third bioassay, 100 eggs of S. frugiperda of different ages (24, 48 and 72 h old) were offered separately to T. pretiosum and T. remus females for 24 h. The variables such as the number of eggs parasitized, parasitoid emergence (%) and female progeny were evaluated. The results indicated that as the age of the T. pretiosum increases, per cent parasitism and adult emergence decreases but age of T. remus females did not affect the number of S. frugiperda eggs parasitized or the emergence of the progeny. However, the sex ratio was more male-biased in the progeny of 1- and 2-day-old females compared to older wasps in the case of T. remus. In the third bioassay, the highest parasitism was observed in 24- and 48-h-old eggs and the per cent emergence decreased with increasing female age. [ABSTRACT FROM AUTHOR]

Trichogrammatid wasps are the most common natural enemies around the world used for biocontrol many important lepidoptran pests. Therefore, the availability of suitable storage methods for these parasitoids is valuable in biological control. In this study, the performance of Trichogramma brassicae reared on two different hosts and in two different cold storage periods was investigated. Wasp pupae formed on Ephestia kuehniella and Ectomyelois ceratoniae eggs, were kept in 10 °C for 30 days and then in 4 °C for 4 and 8 weeks. The effect of the treatment combinations on wasp's emergence rate, sex ratio and the number of female and male parasitoids in parental wasps (F0) and their progeny (F1) were estimated. In addition, adult wasp's shape (wingless and abnormality) and parasitism rate were investigated in parental wasps (F0) and their progeny (F1). The results of this study showed that emergence rate of T brassicae in F0 was significantly influenced by the interaction between host and cold storage period. The highest and lowest emergence rate were respectively found on E. creatoniae in control and E. kuehniella in 8 weeks cold storage period. Sex ratio and the number of female parasitoids in F0 and F1 were significantly influenced either by host or cold storage period, whereas interactive effect of these factors did not affect significantly sex ratio and the number of females in both generations. Also, wingless and abnormality of wasps in F0 was not significantly influenced by any treatment combination. Parasitism rate of wasps reared on both hosts in F1, significantly decreased by increasing in cold storage duration. Finally, the results indicated that the most of qualitative characteristics of wasps grown on E. ceratoniae, were clearly better than those of wasps grown on E. kuehniella both in F0 and F1. [ABSTRACT FROM AUTHOR]

While foraging in agricultural habitats, natural enemies, such as egg parasitoids, may encounter insecticide residues, which, if not lethal, can alter host location behaviour and learning capacity. Such interference can reduce the potential of biological control agents, especially exotic species which are released in small numbers in a new environment and first need to establish and build up their populations. Several studies have investigated the lethal effects of pesticides on parasitoids, but less information is available about non-lethal consequences, and no information is available on the potential effect on associative learning in egg parasitoids. The egg parasitoid Trissolcus japonicus (Ashmed) (Hymenoptera: Scelionidae) is a biological control agent of the invasive brown marmorated stink bug, Halyomorpha halys (Stål) (Hemiptera: Pentatomidae). We hypothesised that a low concentration (causing 20 % parasitoid mortality) of a commonly used neonicotinoid insecticide (acetamiprid) alters the behaviour and learning capacity of T. japonicus to exploit the chemical traces left by reproductive females of either the main host, H. halys, or of an alternative host, Arma custos (F.) (Hemiptera: Pentatomidae). In open arena bioassays, parasitoid females responded positively to traces left by both stink bug species. Following oviposition experience and encounter with host traces (associative learning), T. japonicus reduced foraging time. Parasitoids previously exposed to neonicotinoid showed changes in foraging behaviour, with increased residence time spent in the host-contaminated area and altered kinetics of the walking behaviour. Neonicotinoid exposition did not affect the learning ability of parasitoid females 1 h after oviposition experience but prolonged the memory retention. The insecticide effects on female parasitoid behaviour may affect its reproductive ability and this should be considered when attempting its establishment in the introduction areas.

Native to Asia, the brown marmorated stink bug (BMSB), Halyomorpha halys (Stål) has become a serious invasive pest in North America and Europe. BMSB has an extremely wide host range in both its native and invaded ranges, and can cause severe damage to various tree fruits, vegetables, field crops and ornamentals. Species of Trissolcus are the major egg parasitoids, especially T. japonicus (Ashmead), T. mitsukurii (Ashmead) and Anastatus bifasciatus (Geoffroy) that have recently been studied as biological control agents for this invasive pest. In this study, we report newly a parasitoid parasitizing BMSB eggs collected in Guizhou Province, China, and it was identified as Trissolcus comperei (Crawford) using both morphological and molecular methods. We provide images of T. comperei male, male genitalia and immature stages, and describe some biological characteristics of T. comperei parasitizing BMSB eggs and parasitism capacity. Under 25 ± 1 °C, T. comperei egg hatched within 24 h, larva, prepupa and pupa developed in 1–3, 4–6 and 7–11 d, respectively. The parasitoid could parasitize 0-, 2- and 4-day-old BMSB eggs. Host egg age did not influence emergence rate of adult wasps (90.15–93.33 %). However, both the number of parasitized eggs (0.57–6.07 eggs/ 24 h) and percentage of female progeny (60.00–93.02 %) decreased with increasing host egg age. In addition, we compiled literature to provide a complete list of all 16 known Trissolcus species in China; seven of them have been reported to parasitize BMSB eggs, including T. comperei from this study. This information enriches the knowledge of the egg parasitoids of BMSB. Moreover, the high emergence rate and female-biased offspring of T. comperei could be important attributes as a potential biological control agent for BMSB eggs.

BackgroundAnastatus japonicus Ashmead (Hymenoptera: Eupelmidae) is a solitary egg endoparasitoid that has been studied for inundative biological control of Halyomorpha halys Stål (Hemiptera: Pentatomidae) in China. In this study, we assessed the reproductive attributes and functional response of Anastatus japonicus on a factitious host, Antheraea pernyi (Guérin-Méneville) (Lepidoptera: Anthelidae) at 25 ± 1 °C, 70 ± 5% relative humidity and 16 h:8 h light/dark photoperiod.ResultsThe mean lifetime fecundity of Anastatus japonicus females was 404.3 progeny produced over an average oviposition period of 42.3 days. The sex ratio of adult progeny was slightly male biased (51.2%), whereas more female progeny were produced before day 20 of a female's life. Single 1-day-old mated Anastatus japonicus females exhibited a type II functional response to increasing host densities (1-50 eggs), with an inverse host density-dependent pattern of percent parasitism. The upper limit to the daily attack rate was estimated as 7.6 Antheraea pernyi eggs. Furthermore, mutual interference among Anastatus japonicus females occurred when increasing densities of parasitoids (1, 2, 4, 8, 16) were exposed to 30 host eggs.ConclusionLaboratory functional response result revealed that individual Anastatus japonicus might be unable to respond effectively to increasing host density in the field, which could be compensated by releasing larger numbers of wasps. Strong mutual interference among foraging Anastatus japonicus females should be considered in any future inundative biological control programs for the sustainable management of Halyomorpha halys or other host insect pests. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Trichogrammatid wasps are the most common natural enemies around the world used for biocontrol many important lepidoptran pests. Therefore, the availability of suitable storage methods for these parasitoids is valuable in biological control. In this study, the performance of Trichogramma brassicae reared on two different hosts and in two different cold storage periods was investigated. Wasp pupae formed on Ephestia kuehniella and Ectomyelois ceratoniae eggs, were kept in 10 ᵒC for 30 days and then in 4 ᵒC for 4 and 8 weeks. The effect of the treatment combinations on wasp's emergence rate, sex ratio and the number of female and male parasitoids in parental wasps (F0) and their progeny (F1) were estimated. In addition, adult wasp's shape (wingless and abnormality) and parasitism rate were investigated in parental wasps (F0) and their progeny (F1). The results of this study showed that emergence rate of T. brassicae in F0 was significantly influenced by the interaction between host and cold storage period. The highest and lowest emergence rate were respectively found on E. creatoniae in control and E. kuehniella in 8 weeks cold storage period. Sex ratio and the number of female parasitoids in F0 and F1 were significantly influenced either by host or cold storage period, whereas interactive effect of these factors did not affect significantly sex ratio and the number of females in both generations. Also, wingless and abnormality of wasps in F0 was not significantly influenced by any treatment combination. Parasitism rate of wasps reared on both hosts in F1, significantly decreased by increasing in cold storage duration. Finally, the results indicated that the most of qualitative characteristics of wasps grown on E. ceratoniae, were clearly better than those of wasps grown on E. kuehniella both in F0 and F1

Chelonus inanitus L. (Hymenoptera: Braconidae) is an egg-larval parasitoid of Lepidoptera, with the potential for biological control of noctuids. The lack of information merits research on its reproductive and developmental biology. We studied the reproduction of mated parasitoid pairs during female lifetime and the development of the progeny on two hosts, the factitious Ephestia kuehniella Zeller (Lepidoptera: Pyralidae) and the natural Spodoptera littoralis Boisduval (Lepidoptera: Noctuidae). The longevity of pairs subjected or not to parasitism was compared. Development of the progeny after parasitization and growth rates were studied. Reproduction decreased the longevity of both sexes in every host. The similar survival patterns proved that sex was not a factor influencing longevity. Females parasitized immediately after emergence and offspring production peaked at 2–2.5 days. Low parasitization rates (3–12%) were generally observed. Reproduction on S. littoralis was fourfold less efficient, probably due to failure of immature stages leading to poor progeny. Sex ratio of the progeny was mostly male-biased. Males developed faster in both hosts. Development was 20 days shorter in the natural host. Strikingly, the parasitoid performed successfully better on the factitious host. Inbreeding, poor understanding of host preference, and inadequate rearing and handling practices are discussed as possible causes of the worse parasitoid performance on S. littoralis. [ABSTRACT FROM AUTHOR]

The present study documents novel egg parasitoid-host associations between two genera of baeine wasps and a myrmecomorph spider, Myrmaplata plataleoides (O. Pickard-Cambridge) from West Bengal, India. Until now, no egg parasitoids have been reported from any myrmecomorph spiders. Of the two species, Idris bharati Debnath and Rajmohana sp. nov. is described as new, while Odontacolus markadicus Veenakumari is reported for the first time from the eggs of M. plataleoides. The mt COI DNA barcode sequences for these two species are the only sequences of baeine wasp species from India. Additionally, a preliminary phylogenetic tree has been provided for the members of Idris. Some interesting observations on the nesting behaviour and maternal care of M. plataleoides are also provided. [ABSTRACT FROM AUTHOR]

The present study from the state of Odisha, India, documents for the first time a species of Idris Förster (Hymenoptera: Scelionidae) as an egg parasitoid of a clubionid spider. In Scelionidae, two genera, Ceratobaeus Ashmead and Odontacolus Kieffer, are known to attack clubionids. The emerged species of Idris did not fit the descriptions of congeners; hence, the new species is described and illustrated here as a novel species, Idris hirsutus Sunita and Rajmohana sp. n. The mt COI gene-based molecular characterisation of the species is provided. In addition, a preliminary phylogenetic tree to decipher the placement and broader geographic groupings of Idris on a country-wide scale is discussed. [ABSTRACT FROM AUTHOR]

The egg parasitoid Gryon aetherium Talamas (Hymenoptera: Scelionidae) is a promising candidate for biocontrol of Bagrada hilaris Burmeister (Hemiptera: Pentatomidae) in the Southwestern USA. Bagrada hilaris is a worldwide invasive pest of crops in the family Brassicaceae. The present study aims to evaluate the parasitoid's host range in a European context. These tests complement studies underway in California and provide risk information for a potential release of G. aetherium in southern continental Europe where B. hilaris is likely to spread in the future. Of the 11 nontarget species tested, four pentatomids were in the physiological host range of G. aetherium: Carpocoris mediterraneus, Dolycoris baccarum, Graphosoma italicum and Ancyrosoma leucogrammes. Parasitism rates on these four species were lower in choice than in no-choice conditions. Surprisingly, the three Eurydema spp. that belong to the same tribe as B. hilaris (Strachiini) and feed on plants in the family Brassicaceae were not parasitized. No parasitism was observed on the cosmopolitan invasive pentatomids Nezara viridula and Halyomorpha halys, nor on the rhopalid Liorhyssus hyalinus. Parasitoids that developed from non-target species were larger than ones developing on B. hilaris and took more time to complete development. [ABSTRACT FROM AUTHOR]

We evaluated the induction of plant volatile organic compounds (VOCs) in maize after the attack of two piercing-sucking maize hoppers: the specialist Dalbulus maidis and the oligophagous Peregrinus maidis. We analyzed VOCs in plants after feeding and oviposition by females of both species. We also contrasted VOCs induced by D. maidis males with those induced by females' infestation that comprised oviposition, to evaluate which VOC could be responsible for attracting an egg parasitoid. We quantified the damage performed by both hoppers and tested the behavioral response of the egg parasitoid Anagrus virlai to VOCs emitted by infested and healthy plants. Plants infested by D. maidis females released significantly more VOCs than the other treatments: healthy plants, plants infested by P. maidis females and plants infested by D. maidis males. β-Caryophyllene, α-bergamotene, β-farnesene and cis-3-hexenyl acetate dominated the volatile blend (46%) in plants infested by D. maidis females, while in those plants infested by P. maidis these compounds represented only 17%. Females of both hoppers inflicted a comparable amount of damage, in terms of feeding injuries and number of eggs laid. β-Caryophyllene and cis-3-hexenyl acetate were not induced in plants infested by D. maidis males, that had no oviposited eggs. Finally, females of the egg parasitoid oriented toward VOCs from plants infested by females of the specialist D. maidis, rather than those infested by the oligophagous P. maidis or those infested by D. maidis males. [ABSTRACT FROM AUTHOR]

Simple Summary: The brown marmorated stink bug, Halyomorpha halys, is a pentatomid bug that feeds on a wide range of economically important crops. Crop protection in newly invaded areas mainly relies on the use of broad-spectrum chemical insecticides, while little to no information is available regarding a classical biological control approach. The overall purpose of the present study was to estimate the parasitism rate and development time of the native egg parasitoid Ooencyrtus telenomicida Vassiliev (Hymenoptera: Encyrtidae) when offered H. halys egg-masses, taking into consideration several parameters. Specifically, we tested different parasitoid ages and densities on 1–4-day-old H. halys eggs. According to our results, parasitoid density and the age of host eggs significantly affected the parasitism rate of O. telenomicida. High parasitoid density along with younger host eggs led to higher parasitism rates. Likewise, a significant interaction was observed between the parasitoid density and their age. Successful parasitisation occurred with host eggs up to 4 days old, with parasitism rates decreasing as host egg age increased. A three-fold higher parasitism rate of H. halys eggs was observed when they were parasitised by older O. telenomicida females, compared to younger ones. Concerning the development time of O. telenomicida, individuals that developed in younger host eggs displayed a shorter development time. Parasitoid age did not affect the development time of O. telenomicida, nor did the density of parasitoids. Halyomorpha halys (Hemiptera: Pentatomidae) is an invasive pest species that was imported into Greece in 2011 and since then, has caused severe qualitative and quantitative damage to economically important crops. Its management relies mainly on the use of broad-spectrum insecticides, with little to no information available concerning the potential use of native parasitoids in terms of classical biological control. Our study aimed to assess the parasitism rate and development time of the gregarious egg parasitoid Ooencyrtus telenomicida (Hymenoptera: Encyrtidae) on H. halys egg-masses, depending on several factors such as: (i) age of parasitoids, (ii) density of parasitoids, (iii) age of host eggs, and (iv) oviposition experience of parasitoids. According to our results, the younger the host eggs and the more parasitoids, the higher the parasitism rate achieved by adults of O. telenomicida, with the maximum mean value of the parasitism rate observed with 1-day-old host eggs and 4 parasitoid pairs (57.3%). On the contrary, the lowest mean value of the parasitism rate was observed with 4-day-old host eggs and 1 parasitoid pair (6.5%). Similarly, the age of parasitoids significantly affected parasitisation. The older the parasitoids were, the higher the parasitism rate achieved by adults of O. telenomicida, with a three-fold higher parasitism rate observed at 3–4 and 5–6-day-old O. telenomicida, compared to 1–2-day-old (31.8, 32.4, and 12.1%, respectively). Individuals that developed in younger host eggs displayed a shorter development time, and the shortest development time was observed for O. telenomicida laid by 2 parasitoid pairs. Parasitoid age did not affect the development time of O. telenomicida, although there was a tendency for individuals laid by younger female parasitoids to exhibit a shorter development time. Our findings provide valuable information on the potential use of O. telenomicida as a biocontrol agent of H. halys. [ABSTRACT FROM AUTHOR]

The parasitoid wasp, Ooencyrtus kuvanae (Howard) (Hymenoptera: Encyrtidae), is a natural enemy of the spongy moth, a significant forest pest in North America. We investigated the oviposition behavior of O. kuvanae females on spongy moth egg masses by (i) presenting female parasitoids with a single spongy moth egg mass that was replaced every day, 2nd day, 4th day, 8th day, or 16th day (which is the total length of the oviposition period) and (ii) presenting female parasitoids with 1, 2, 4, or 8 egg masses at a time. Offspring developmental length ranged from 18 to 24 days. On average, male offspring exhibited faster developmental times, emerging approximately 1 day ahead of females. The amount of time that adult females spent on an egg mass affected the number of parasitized eggs. Specifically, more offspring emerged in the 4-, 8-, and 16-day treatments than in scenarios involving daily or every second-day egg mass replacement. The percentage of male offspring decreased as the number of egg masses presented to females increased. Interestingly, the total number of female offspring remained constant, but the number of male offspring decreased with an increase in the number of egg masses and time spent by the parent within a patch. The observed sexual dimorphism in development time, the influence of resource availability on offspring sex ratios, and flexible oviposition patterns illustrate the adaptability of O. kuvanae in response to varying conditions. These insights have implications for our understanding of parasitoid–host interactions and their potential role in biological control strategies. [ABSTRACT FROM AUTHOR]

Specimens of an egg parasitoid wasp, Telenomus cristatus Johnson (Platygastroidea, Scelionidae), were reared from stink bug egg masses collected in the wild, in Maryland, United States. The egg masses were identified morphologically as Halyomorpha halys (Stål), Banasa Stål and Euschistus Dallas (Hemiptera, Pentatomidae). Molecular tools were used to further identify the Euschistus egg masses as E. servus (Say) and E. tristigmus (Say). All of these are new host associations for Te. cristatus. We also provide data to contribute to future identification of Te. cristatus: images of the holotype specimen and COI sequences from two disparate localities.

The European pepper moth (Duponchelia fovealis) is predominant in the main strawberry production areas, including Brazil, as an important invasive pest and causes substantial damage to the crop. This damage is mainly attributed to the lack of effective management strategies. A promising alternative for managing this pest is implementing biological control through releasing natural enemies. This study determined the dispersal capacity of Trichogramma pretiosum for the management of D. fovealis in a strawberry crop in a low tunnel system 24, 48, and 72 h after parasitoid release. The experiments were carried out on strawberry farms in the mountainous region of Espírito Santo. Tunnels measuring 1.20 m wide by 50 m long were selected, in which artificial infestations of 30, 60, 90, and 120 eggs of D. fovealis were made on both sides of the strawberry tunnel at distances of 3, 7, 11, and 15 m, respectively, from the central point where the parasitoids were released. After the initial 24 h, new eggs were placed to replace the infested ones; the replacement was repeated at 48 and 72 h. The results indicated that, in strawberry plantations, T. pretiosum was efficient in parasitism. There was no difference between parasitism 24 and 48 h after parasitoid release, but parasitism was substantially lower after 72 h. The dispersion capacity of T. pretiosum was 14.21 linear meters, corresponding to an area of 17.05 m2. It is recommended that 93,000 T. pretiosum females be released per hectare every three days.

Integrated pest management relies upon mutual compatibility among pest control tactics. The fruit-boring moths Carposina sasakii and Grapholita molesta can be devastating pests of pome and stone fruit production. Trichogramma dendrolimi parasitizes the eggs of these pests, preventing their eclosion, but its efficacy can be reduced by other pest control tactics. We tested T. dendrolimi attraction to five colors, and moth attraction to six colors, in laboratory choice tests, and thereafter deployed yellow sticky cards in tandem with releases of T. dendrolimi in field trials in a pear orchard. Yellow sticky cards deployed at high density trapped T. dendrolimi and reduced their numbers post-release. They also trapped adult G. molesta, which appeared to compensate for reduced egg parasitism on this species, but not on C. sasakii, which had higher abundance in plots with yellow sticky cards. The cards also captured adult lacewings, likely reducing their numbers in the field, but did not capture large numbers of lady beetles. The results suggest that yellow sticky cards can be used at high density to control aphids, psyllids and leafhoppers in early spring (March and April) when natural enemies are in low numbers, then removed in May so as not to interfere with augmentative releases of T. dendrolimi that must be timed to coincide with peak flights of fruit-boring moths. This strategy should enhance the compatibility of yellow sticky cards with egg parasitoid releases.

Abstract Background Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is one of the new alien destructive pests of maize and other 350 economic crops. The majority of farmers are still depended upon chemical insecticides to suppress the pest, but S. frugiperda has succeeded to develop resistance against most of the chemical families. Improving an effective environmentally-friendly approach is highly recommended. Therefore, the egg parasitoids are the best weapon for managing the FAW in the early egg stage due to the feeding behavior of their larvae. In this regard, the impact of FAW egg mass layers and scale thicknesses, as physical barriers, on the parasitic performance of the egg-parasitoid species, Trichogrammatoidea bactrae Nagaraja (Hymenoptera: Trichogrammatidae), in non-choice and choice tests was assessed. Besides, the efficacy of FAW-produced adult wasps on the next generation based on the rates of parasitism, adults' emergence, and female progeny was determined. Results Obtained results exhibited that T. bactrae was able to parasitize all exposed FAW egg masses but with different rates related to the layers’ number and scales' thicknesses in both tests. One-layer (83.18, 78.24%) and two-layer egg masses (65.99, 76.42%) had significantly the highest parasitism rate, while three layers (42.15, 46.05%) was the least one, in both tests, respectively. All parasitoids emerged after 10–12 days with high rates (~ 88–98%) from all the tested egg masses, and the majority offspring were female-biased in both tests. Furthermore, parasitic performance in F1 progeny was similar with that recorded in parental generation in terms of parasitism rate, high parasitoid emergency (~ 87–95%), and strongly female-biased (~ 68–76%) in all the exposed egg masses. Conclusions The egg parasitoid, T. bactrae, could be an efficient and recommended bio-control agent against FAW as its greatest ability to overcome the layers’ number and scales’ thickness.

Tecia solanivora (Povolný 1973), is a quarantine pest in Europe. Identified in Guatemala in the 1970s, it spread throughout Central and South America, reaching the Canary Islands in 1999 and mainland Spain in 2015. The pest has caused prohibitive economic losses both in the field and in storage, where losses can reach 100%. In the absence of approved chemical treatments, the use of an egg predatory mite, Blattisocius tarsalis (Berlese 1918), and the egg parasitoid, Trichogramma euproctidis (Girault 1911), is being studied for use in storage. Previous laboratory studies have confirmed their potential for use in non-refrigerated stores, typically between 15 and 20 °C. In the present work, we compared the efficacy of both natural enemies under semi-storage conditions. We observed that while both T. euproctidis and B. tarsalis reduced the T. solanivora populations (with an efficacy of 82.95 ± 7.32% and 49.06 ± 2.69%, respectively) and the number of mites per tuber, only B. tarsalis resulted in undamaged tubers (65%). For this reason, the mite was selected and tested in storage conditions, obtaining promising results in the protection of infested tubers, suggesting potential for further investigation, adaptation and standardization of its use in real conditions. [ABSTRACT FROM AUTHOR]

The egg parasitoid Cleruchoides noackae Lin & Huber, 2007 (Hymenoptera: Mymaridae) is originated from Australia and the main biological control agent of Thaumastocoris peregrinus Carpenter & Dellapé, 2006 (Hemiptera: Thaumastocoridae) on Eucalyptus L'Hér (Myrtaceae). Companies that grow Eucalyptus are in need of a mass rearing protocol to increase the number of individuals produced and improve the quality of this parasitoid. The aim of this study was to define a protocol for mass rearing C. noackae in T. peregrinus eggs, based in the evaluations of the key biological attributes of this parasitoid in the parental and F1 generations, after the cold storage of the parasitised host eggs. Two methods were tested as C. noackae rearing protocols. In the first, parasitised eggs of T. peregrinus by C. noackae were cold stored for 7 days after being left in a climatic chamber at 24 ± 2°C, 60 ± 10% RH and a photoperiod of 12:12 (light:dark) h (standard environmental conditions) for 3, 6, 9 or 12 days. In the second, T. peregrinus eggs parasitised by C. noackae were maintained in a climatic chamber under standard environmental conditions for 6 days, after which these eggs were cold-stored for 0 (control), 7, 14 or 21 days. Parasitism (%), and the development period (parasitism to adult) and female proportion (%) of C. noackae were evaluated. Based on the results (parental generation: parasitism, around 45%; F1 generation: parasitism, around 55%; development period, around 16 days; female proportion, around 60%), eggs should be stored at 5°C on the sixth day after parasitism by C. noackae and maintained at this temperature for 7 days. The cold storage of T. peregrinus eggs, after parasitism, can be included in the mass rearing protocols of the parasitoid C. noackae. [ABSTRACT FROM AUTHOR]

Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is the most destructive pest of tomato worldwide. Biological control has always been considered as a promising management approach of this pest in tomatoes. In this context, we evaluated the effectiveness of releasing Trichogramma cacoeciae Marchal parasitoids or Macrolophus pygmaeus (Rambur) predators in controlling T. absoluta in greenhouse tomatoes of northeastern Tunisia. Two weekly releases of either M. pygmaeus at 1 adult/m2 or T. cacoeciae at 20 adults/plant were assessed. Our results indicated that parasitism rates were significantly higher on the apical tomato leaves compared to the middle leaves. We found that the number of T. absoluta eggs and larvae was significantly reduced after releasing T. cacoeciae, while releases of M. pygmaeus did not significantly reduce T. absoluta densities. The present study demonstrated the great potential of releasing T. cacoeciae in controlling T. absoluta in greenhouse tomatoes of northeastern Tunisia. However, further studies are needed to evaluate other release rates of M. pygmaeus that could show promising effectiveness against T. absoluta in northeastern Tunisian greenhouses. [ABSTRACT FROM AUTHOR]

Specimens of an egg parasitoid wasp, Telenomus cristatus Johnson (Platygastroidea, Scelionidae), were reared from stink bug egg masses collected in the wild, in Maryland, United States. The egg masses were identified morphologically as Halyomorpha halys (Stål), Banasa Stål and Euschistus Dallas (Hemiptera, Pentatomidae). Molecular tools were used to further identify the Euschistus egg masses as E. servus (Say) and E. tristigmus (Say). All of these are new host associations for Te. cristatus. We also provide data to contribute to future identification of Te. cristatus: images of the holotype specimen and COI sequences from two disparate localities. [ABSTRACT FROM AUTHOR]

BACKGROUND: Tuta absoluta is an exotic species and a major pest of tomato crops in Europe. Macrolophus pygmaeus and Trichogramma achaeae are two biocontrol agents widely used in integrated pest management programs of the South American tomato pinworm Tuta absoluta. In this study, we evaluated under laboratory conditions the (i) voracity of M. pygmaeus females fed on single diets of Tuta absoluta eggs parasitized or unparasitized by Trichogramma achaeae, (ii) voracity and feeding preference of M. pygmaeus females provided with mixed diets of Tuta absoluta eggs unparasitized and parasitized by Trichogramma achaeae and (iii) effect of competitive and intraguild interactions between M. pygmaeus and Trichogramma achaeae on the number of Tuta absoluta eggs consumed and/or parasitized. Lastly, we assessed under field conditions the effect of interspecific and intraspecific interactions between natural enemies on the number of Tuta absoluta eggs consumed and/or parasitized. RESULTS: Macrolophus pygmaeus consumed more unparasitized than parasitized eggs of Tuta absoluta. Under mixed diet regimes, Manly indices revealed a feeding preference for unparasitized eggs, and a decrease in the total number of eggs consumed, as the proportion of available parasitized eggs increased, whereas the unparasitized eggs were consumed in direct proportion to their availability. Conspecific interactions between M. pygmaeus, in contrast to Trichogramma achaeae, revealed the possible occurrence of intraspecific competition. For intraguild heterospecific interactions, the number of Tuta absoluta eggs consumed by M. pygmaeus and parasitized by Trichogramma achaeae was lower than that predicted for additive and non‐interactive scenarios. Under field conditions, a significant difference between the conspecific treatment and heterospecific treatments revealed a slightly higher success rate in controlling Tuta absoluta when both M. pygmaeus and Trichogramma achaeae were used simultaneously. CONCLUSION: Macrolophus pygmaeus prefers unparasitized eggs of Tuta absoluta but inflicts intraguild predation on Trichogramma achaeae. In conspecific experiments, mutual interference between M. pygmaeus predators intensifies as the number of individuals increases, but for Trichogramma achaeae, it occurs in an unpredictable manner. Adding Trichogramma achaeae could significantly increase the level of control of Tuta absoluta compared to what could be achieved when only M. pygmaeus is present in glasshouse tomatoes. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Bagrada bug, Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae), is an invasive pest of cruciferous crops. The parasitoid Gryon aetherium Talamas (Hymenoptera: Scelionidae) is a promising biological control agent for B. hilaris because it can forage in the soil where B. hilaris deposits most of its eggs. In this study, we assessed parasitism by G. aetherium on B. hilaris eggs in situ in northcentral California, including the Salinas Valley where most cruciferous crops in the United States are grown. Parasitism was documented by leaving soil-filled trays under infested plants for 7–14 days, then removing eggs and holding them for emergence of parasitoids. Gryon aetherium accounted for over 99% of emerged parasitoids, and occurred at 11 of the 12 sampled sites. Of the 17,729 and 31,759 B. hilaris eggs collected in 2021 and 2022, 1,518 (8.84%) and 2,654 (8.36%) were parasitized by G. aetherium , respectively. Parasitism rates were generally higher inland and ranged from 3.64% to 44.93% in 2021 and from 1.01% to 23.04% in 2022, and never exceeded 15% on any sample dates at several coastal sites in the Salinas Valley. Discovery efficiency (a measure of the ability of parasitoids to locate egg patches) reached 80% or higher at all but 1 site, but exploitation efficiency (a measure of the ability of parasitoids to exploit the egg patch after it has been discovered) was generally <20%, suggesting that G. aetherium can locate egg patches efficiently but is less efficient at finding eggs within patches. [ABSTRACT FROM AUTHOR]