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Trichogramma spp. wasps are egg parasitoids with a long history of mass rearing for augmentation biocontrol programs in field crop and orchard landscapes. Supplementary nutrition can improve the longevity, fecundity, and biocontrol efficacy of parasitoids. To improve the production efficiency and parasitism performance of Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae), the present study screened and examined the potential supplementary nutrients for this biological control agent. Dietary supplementation with a 10% sucrose solution significantly increased wasp longevity and parasitism potential of T. dendrolimi on host eggs, but provision of pollen did not provide additional benefits. Laboratory and greenhouse cage tests demonstrated that wasp access to soybean aphid Aphis glycines Matsumura (Hemiptera: Aphididae) honeydew, comprised primarily of melezitose and trehalose, improved T. dendrolimi longevity and parasitism. In conclusion, provision of a 10% sucrose solution to adult wasps will enhance the mass-rearing efficiency of T. dendrolimi; furthermore, field release of T. dendrolimi by plant vectors bearing honeydew-producing aphids holds promise for improving the biocontrol efficacy of T. dendrolimi., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The egg parasitoid Mesocomys trabalae Yao, Yang, and Zhao is used as a biocontrol agent against the emerging defoliator pest Caligula japonica Moore in East Asia. It has been proven that the eggs of Antheraea pernyi Guérin-Méneville can be used as a factitious host for the mass production of M. trabalae. We examined the parasitic behavior and morphological characteristics of the developmental stages of M. trabalae reared on A. pernyi eggs. The parasitic behavior of M. trabalae encompasses 10 steps, involving searching, antennation, locating the oviposition site, drilling, probing, detecting, oviposition, host feeding, grooming, and resting, with the oviposition step further divided into 3 stages. We determined that the parasitoid released an egg during the second stage of the oviposition step, while her body remained in a relatively static state. Among all the steps in parasitic behavior, probing occupied the longest time, accounting for 26.33% of the entire parasitism process. It was followed by oviposition (15.88%), drilling (15.10%), antennation (13.09%), detecting (10.79%), host feeding (10.02%), and the remaining steps, each occupying less than 5.00% of the total time in steps. The pre-emergence of adult M. trabalae comprised of 4 stages: egg (0-1 day), larva (2-6 days), prepupa (7-11 days), pupa (12-20 days), followed by the development into an adult, and it usually took 20-22 days to develop from an egg into an adult at 25°C. This study advances our understanding of the biology of Mesocomys parasitoids and their mass-rearing for use in augmentation programs., (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Lethal and sublethal effects of insecticides used in organic agriculture were tested against Anastatus reduvii and Telenomus podisi, native North American hymenopteran egg parasitoids of the native Euschistus servus Say (Hemiptera: Pentatomidae) and the invasive Halyomorpha halys Stål. Entrust (spinosad), PyGanic (pyrethrin), Neemix (azadirachtin), and Azera (pyrethrin + azadirachtin) were tested at equivalent field rates of 1×, 0.5×, and 0.1×. Bioassays included insecticide exposure to parasitoids through residue on substrate, parasitized host eggs, and their food source. When exposed to dried residues, Entrust caused 100% mortality at the 0.5× rate to both species; PyGanic, Neemix, and Azera exhibited low toxicity. Exposure of parasitized host eggs to Entrust 1× during the egg stage of parasitoid development reduced parasitoid emergence compared to all other treatments in both species. Anastatus reduvii emergence was also reduced by PyGanic at 0.5× and 1×. Parasitoid emergence from host eggs exposed during the pupal stage was more variable than egg stage exposure; emergence of both species was reduced in 0.5× and 1× rates of PyGanic, and A. reduvii was reduced in the 0.5× rate of Entrust compared to controls. Longevity of emerged parasitoids surviving exposure within host eggs showed that Entrust was more deleterious than Neemix or PyGanic. When A. reduvii was fed insecticide-laced honey, all treatments except Neemix at 0.1× reduced adult longevity compared to the control. These studies demonstrated that insecticides commonly used in organic agriculture can negatively affect two common parasitoids of stink bugs; specifically, negative effects were most pronounced with Entrust, and variable with Neemix and Pyganic.

Psix saccharicola (Mani) (Hymenoptera: Platygastridae) is a solitary egg parasitoid of the pistachio green stink bug, Acrosternum arabicum (Wagner) (Hemiptera: Pentatomidae), which is one of the most important pests of pistachio in Iran. Augmentation of P. saccharicola field populations using mass-reared individuals may provide an alternative to conventional pesticide use for pistachio green stink bug control. Cold storage is an important component of mass-rearing protocols for optimum timing of host egg parasitization and potentially extended storage of P. saccharicola pupae prior to adult emergence. The impact of cold storage on A. arabicum eggs for various time intervals at 4.0°C was investigated. Results indicated that host eggs stored at 4.0°C for up to 60 d could be exploited by P. sacchricola, whereas no offspring were produced when eggs were stored for 120 d. The emergence rates of the F1 and F2 generations declined with increased host egg storage time. Both sex ratio and survival rate of the F2 generation decreased as the refrigeration time of host eggs increased. The impact of cold storage on P. saccharicola pupae was evaluated. Reared pupae of P. saccharicola were held for 1 wk at three temperatures and compared with a control (27 ± 1°C). Psix saccharicola pupae were tolerant to cold storage at 8 and 12°C. Cold storage adversely affected mean adult emergence at 4°C, which decreased following low temperature exposure. Furthermore, mean percentage survivorship was unaffected by storage at low temperatures in the F1 generation, but was reduced at 4°C. The sex ratio of the F1 generation became more male-biased when held at lower storage temperatures. The highest female proportion was observed at 12°C.

Early instar larvae of the tobacco cutworm Spodoptera litura (Lepidoptera: Noctuidae) and the beet armyworm Spodoptera exigua (Lepidoptera: Noctuidae) are recognized hosts of the parasitic wasp Microplitis prodeniae Rao and Kurian (Hymenoptera: Braconidae), although M. prodeniae has previously been regarded as monophagous. In this study, we found the immature period and longevity of M. prodeniae developing in S. exigua was similar to that in S. litura. It was shown that the development time of M. prodeniae in S. exigua was 15.1 ± 0.3 d, not significantly different from 15.0 ± 0.2 d in S. litura. The parasitism rate of M. prodeniae attacking S. exigua was significantly lower than on S. litura (65.48 ± 2.29 and 43.83 ± 2.20%, respectively), whilst the female ratio of the wasp's offspring was not significantly different when developing on the two species. M. prodeniae females prefer to oviposit on the second- and third-instar host larvae of S. exigua, rather than other instars. The effects of development of M. prodeniae on two important lepidopterous pests are discussed.

Little information is available regarding the lethal and sublethal effects of pesticides on Trichogramma achaeae (Nagaraja and Nagarkatti; Hymenoptera: Tricogrammatidae) during integrated management of Tuta absoluta (Meyrick; Lepidoptera: Gelechiidae), an important pest for tomato production. Twenty-two pesticides sprayed on Ephestia kuehniella (Zeller; Lepidoptera: Pyralidae) eggs were evaluated on the mortality of adult parasitoids upon contact with the hosts 24 h after the treatments and their sublethal effects on the parasitoids were assessed in laboratory conditions. Tests were carried out with fresh solutions at the recommended concentration. According to the International Organisation for Biological and Integrated Control (IOBC) standards, chlorpyrifos is harmful to the parasitoid; merthiocarb, methomyl, spinosad lambda-cyhalothrin, and acrinatrin are moderately harmful; and chlorantraniliprole, lufenuron, hexythiazox, cyromazine and Bacillus thuringiensis have no effect on the parasitoid. Sulfur is slightly harmful, and azoxystrobin is harmless. Chlorpyrifos was the most lethal among these pesticides and killed all females in less than 24 h. All other pesticides affected the biological parameters of T. achaeae to varying degrees. Regarding the lethal and sublethal effects, merthiocarb and spinosad killed all female offspring in less than 24 h; lambda-cyhalothrin and sulfur reduced the number of parasitized eggs; and acrinatrin, deltamethrin and azoxystrobin affected the emergence rate. After that, we can recommend the use of chlorantraniliprole and B. thuringiensis to control Lepidoptera, cyromazine to control Diptera, pirimicarb to control Homoptera, hexythiazox to control mites and azoxystrobin can be used as fungicide in an integrated pest management program with mass released of T. achaeae.

Many female parasitoid wasps optimize host selection to balance the benefits of high-quality hosts and the costs of predator- or hyperparasitoid-induced mortality risks to maximize their fitness. Cannibalism exists in many insect species and affects survival of parasitoid larvae developing in or on parasitized hosts. However, little is known about how parasitoid wasps resolve the fitness consequence of host cannibalism-induced mortality risk during host selection. We examined the effect of oothecal age on cannibalism in the American cockroach Periplaneta americana (L.) (Dictyoptera: Blattidae) and its effect on host age selection and fitness of its oothecal parasitoid Evania appendigaster (L.) (Hymenoptera: Evaniidae). P. americana differentially cannibalized 1-d-old (30‒60%) versus 10- to 40-d-old oothecae (<9%). However, parasitoid females did not avoid but still preferred to parasitize 1-d-old (45%) over 10- to 40-d-old oothecae (1.6‒20%). The parasitism rate was greater and the handling time was shorter on 1-d-old compared to older oothecae. For parasitoid progeny emerging from different-aged oothecae, regression analysis showed that development time increased and body size (measured as hind tibia length) and longevity decreased with oothecal age. These results demonstrate that reduced parasitoid progeny survival due to host cannibalism did not change the parasitoid's oviposition preference for newly laid oothecae, and that E. appendigaster females traded progeny survival for fitness gains for themselves and their progeny., (© The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The study of the technical and economic aspects of rearing natural enemies is essential for its effective use as a biological control agent in the field. The aim of this study was to determine the cost of production of the parasitoid, Telenomus remus (Nixon; Hymenoptera: Platygastridae), reared in eggs of its natural host, Spodoptera frugiperda (J. E. Smith; Lepidoptera: Noctuidae), and the alternative host, Corcyra cephalonica (Stainton; Lepidoptera: Pyralidae). The insects were reared in accordance with their respective methodologies of laboratory rearing. The cost of production of this biocontrol agent is US$ 0.0004 when reared with S. frugiperda eggs and US$ 0.0002 with C. cephalonica eggs., (© The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The purpose was to evaluate the side effects of strains Metarhizium anisopliae (Metsch.) Sorokin sensu lato Unioeste 43 and M. anisopliae sensu stricto ESALQ 1641 on Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) under controlled conditions. A free-choice test for parasitism was performed, with the confinement of T. pretiosum females mated with cards (1 × 5 cm) containing age-standardized Anagasta kuehniella Zeller eggs, either sprayed with a fungal strain (109 conidia/ml) or 0.01% v/v Tween 80 (control). For the no-choice tests, T. pretiosum females mated were confined with cards sprayed with fungal strains before or after parasitism, and cards with fungal applications at different times. The number of parasitized eggs, percentage of emergence, longevity, egg-to-adult period, sex ratio, total and confirmed mortality by the fungus, and longevity of females that parasitized previously sprayed eggs, were assessed. Histological analysis of immature phases was also performed. The fungus was repellent to T. pretiosum in the free-choice test, while in the no-choice test, fungal applications before and after parasitism did not affect the number of eggs parasitized by T. pretiosum or the sex ratio of emerging adults. However, both strains affected adult emergence rates, the egg-to-adult period, and longevity. Overall, both M. anisopliae strains had minor effects on these biological parameters of T. pretiosum under controlled conditions. Hyphae were not detected in histological observations of immature stages of the parasitoid., (© The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Spirotetramat, a lipid biosynthesis inhibitor, is effective against sucking insect pests but harmless to insect natural enemies. As spirotetramat can be registered for the management of sucking insect pests such as aphids and bugs in soybeans, we evaluated the insecticide against Riptortus pedestris (Fabricius) (Hemiptera: Alydidae), one of the most important soybean pests in Korea, as well as its effect on two of its important egg parasitoids, Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) and Gryon japonicum (Ashmead; Hymenoptera: Platygastridae). Oral toxicities of five concentrations of spirotetramat (1.00, 0.50, 0.25, 0.13, and 0.06 ml/liter) were tested by feeding these test solutions to insects for 24 h after 12 h of starvation. The lethal median concentration (LC50) for second instars of the bean bug was 0.3 ml/liter after 48 h while values for fourth instars and adults were 9.2 and 19.0 ml/liter, respectively. The median lethal time (LT50) for bean bugs when exposed to a concentration of 0.50 ml/liter was 1.2-1.5 times less than that of the control, while in G. japonicum and O. nezarae it was 1.1-1.2 times less than the control. These results show that spirotetramat is less toxic to the egg parasitoids of bean bug than to bean bug itself and would thus be useful in an integrated management program for this pest., (© The Author 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The Cnaphalocrocis medinalis (Guenée) is one of the most important rice pests in Asia and is difficult to control by chemical insecticides due to its rapid development of resistance. To screen potential species for biological control of C. medinalis, we investigated the effects of temperature (20, 24, 28, 32, and 36 °C) and host age (1-, 2-, 3-, and 4-d-old) on the fecundity of four Trichogramma spp. on C. medinalis eggs. Our results indicated that C. medinalis eggs were acceptable to T. japonicum, T. chilonis, T. dendrolimi, and T. ostriniae, though no eggs were parasitized at 36 °C. There were no significant differences in parasitism among the four Trichogramma species under the tested temperature regions, except at 20 °C where parasitism by T. japonicum was significantly higher than that by T. chilonis and T. ostriniae. However, T. japonicum had significantly more progeny than the other three Trichogramma species at 32 °C. All four Trichogramma species performed well on 1-, 2-, and 3-d-old C. medinalis eggs, but parasitism on 4-d-old eggs was significantly reduced. Trichogramma japonicum parasitized the highest number of C. medinalis eggs on different aged hosts and had more progeny than the other Trichogramma species, especially on 3-d-old hosts. In conclusion, T. japonicum exhibited better performance on C. medinalis eggs than the other three Trichogramma species and could be considered as our most suitable Trichogramma candidate for control of C. medinalis., (© The Authors 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The influences of ootheca age and temperature on the life history of Aprostocetus hagenowii (Ratzeburg) (Hymenoptera: Eulophidae), a gregarious ootheca parasitoid of the American cockroach Periplaneta americana (L.) (Dictyoptera: Blattidae), were evaluated. Oothecae were incubated at 20, 25, and 30 °C to produce oothecae aged 1-60, 1-40, and 1-30 d old, respectively. Fitness traits (development time, percentage emergence, number of progeny, percentage female progeny, and female body size) of A. hagenowii developing in these different-aged oothecae were determined. For oothecae incubated at 20, 25, and 30 °C, parasitoids successfully developed in oothecae aged up to 50, 30, and 20 d old, which represent 72.9%, 65.9%, and 61.9% of the total embryonic development time of P. americana, respectively, without any changes in their fitness traits. When A. hagenowii from oothecae kept at constant temperatures (20, 25, 30, 32, and 35 °C) were compared, the immature development time (71.0-34.0 d) and adult life span decreased with increasing temperature. No parasitoid emerged at 35 °C. The lower, upper, and optimal temperature-dependent developmental thresholds were 9.5, 34.2, and 31.1 °C, respectively. Thermal constant for total immature development was 666.7 degree-days. Temperature did not affect lifetime realized fecundity and number of oothecae parasitized by females but did influence parasitism activities over time. Sugar-fed females sustained longer periods of high parasitism rates (≥70%) at 20-30 °C (15-30 d) than at 32-35 °C (1-5 d). These results are useful for determining the ootheca age and temperature range optimal for parasitoid rearing and for estimating the effectiveness of biological control by the wasps., (© The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

It is common for a female trichogrammatid to lay more than one egg per host, a phenomenon known as self-superparasitism, which exposes her offspring to intraspecific, intrinsic competition (IIC) with its own siblings. Information about how often self-superparasitism occurs and how IIC interacts with abiotic factors is rare, especially regarding the Neotropical Trichogramma species. Here we determined the frequency of self-superparasitism in Trichogramma atopovirilia Oatman & Platner (Ta) and T. pretiosum Riley (Tp), and the effects of IIC and temperature on the sex ratio, egg-to-adulthood period, and survivorship of both species' offspring. Individual females were offered eggs of Spodoptera frugiperda (J.E. Smith) for 30 min. A group of parasitized hosts was then dissected for determination of the self-superparasitism frequency, while another group was incubated at 15, 18, 21, 24, 27, 30, and 33°C. High rates of self-superparasitism were found in both Ta (0.55 ± 0.07) and Tp (0.62 ± 0.06). IIC interacted with temperature decreasing Ta and Tp's survivorship, lengthening the egg-to-adulthood period in Tp and shortening it in Ta, and balancing Ta's sex ratio. Based on survivorship rate, Ta and Tp could not be differentiated if their immatures develop in absence of IIC. However, in its presence, Tp was 3 × more likely to survive than Ta at 33°C, while at 15°C Ta survived 2× better than Tp These results show that self-superparasitism can be very common in both Ta and Tp, and that its effects on the species' biological traits and competitiveness strongly depend on the IIC-temperature interaction., (© The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Trichogramma spp. are egg parasitoids largely used worldwide for biological control of lepidopteran pests. Host quality (related to host size and age, host species, etc.) can influence parasitism preference and fitness of the parasitoid offspring. However, few studies have documented the performance of Trichogramma parasitoids when they parasitize nonfertilized eggs of their lepidopteran hosts. In the present study, we investigated the performance of three indigenous Trichogramma species ( Trichogramma japonicum Ashmead, Trichogramma dendrolimi Matsumura, and Trichogramma chilonis Ishii) on fertilized and nonfertilized eggs of their native host, Chilo suppressalis (Walker). The results showed that the three Trichogramma species tested could recognize fertilized and nonfertilized eggs of C. suppressalis . The different fertilization status eggs of C. suppressalis were all accepted by T. japonicum , T. chilonis , and T. dendrolimi with a clear tendency that they preferred to parasitize fertilized eggs whether under no-choice or choice conditions. All Trichogramma species successfully completed development in parasitized eggs of C. suppressalis regardless if the host eggs were fertilized or not. There was similar adult emergence rate, development time, and female progeny between fertilized and nonfertilized eggs for all Trichogramma species with an exception of development for T. chilonis . Trichogramma chilonis had shorter developmental time in fertilized eggs than in nonfertilized ones. Whether in fertilized or nonfertilized eggs, T. dendrolimi had longer development time than other two Trichogramma species. However, T. dendrolimi had the largest percentage of female progeny on fertilized eggs, followed by T. japonicum , and T. chilonis had the least percentage of female progeny. The present study indicates that Trichogramma parasitoids (i) can distinguish fertilized vs. nonfertilized host eggs, and (ii) could use nonfertilized host eggs for successful offspring development (despite showing lower preference for such eggs) [corrected]., (© The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The tomato leafminer, Tuta absoluta (Meyrick), had established in Israel by 2010, attacking both open-field tomatoes and greenhouse crops.We searched for its natural enemies in open-field tomatoes, and tried to determine their potential for controlling this pest. We surveyed the local natural enemies in open tomato fields and measured their impact on pest populations in an unsprayed field. We assessed the suppressive ability of the dominant hemipteran predator, Nesidiocoris tenuis Reuter, against T. absoluta under controlled laboratory conditions and evaluated the impact of its augmentation on T. absoluta control in open-field tomatoes. We found five natural enemy species:the predator, N. tenuis, two braconids, and two eulophids. Predation accounted for 64.5±9.2% (mean ± SE) of T. absoluta larval mortality, whereas parasitism accounted for 20.96±7.5%. Together, they eliminated the pest population at tomato harvest time. Under controlled conditions, predation by N. tenuis rose from 58 to 72% with increased density of T. absoluta, suggesting positive density dependence. The reduction of T. absoluta (83%) by N. tenuis was higher than that of Bemisia tabaci (32%), suggesting a preference of N. tenuis for T. absoluta. Augmentation of N.tenuis was as effective as conventional treatment insecticide treatment, and plant damage was low and did not seem to affect yield. Results indicate that reduced pesticide use enables indigenous natural enemies, particularly N.tenuis, to successfully control T. absoluta and prevent crop damage in open-field tomatoes.

Euschistus servus (Say), Nezara viridula (L.), and Chinavia hilaris (Say) (Hemiptera: Pentatomidae) are economic pests of cotton in the coastal plain of the southeastern United States. The objective of this 2-yr study was to determine the ability of trap cropping systems, pheromone-baited stink bug traps, and a synthetic physical barrier at the peanut-to-cotton interface to manage stink bugs in cotton. The physical barrier was the most effective management tactic. Stink bug density in cotton was lowest for this treatment. In 2010, boll injury was lower for the physical barrier compared to the other treatments except for soybean with stink bug traps. In 2011, boll injury was lower for this treatment compared to the control. Soybean was an effective trap crop, reducing both stink bug density in cotton and boll injury regardless if used alone or in combination with either stink bug traps or buckwheat. Incorporation of buckwheat in soybean enhanced parasitism of E. servus egg masses by Telenomus podisi Ashmead in cotton. The insertion of eyelets in the lid of the insect-collecting device of a stink bug trap allowed adult stink bug parasitoids, but not E. servus, to escape. Stand-alone stink bug traps were not very effective in deterring colonization of cotton by stink bugs or reducing boll injury. The paucity of effective alternative control measures available for stink bug management justifies further full-scale evaluations into these management tactics for control of these pests in crops., (Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.)

Dasineura mali Kieffer (Diptera: Cecidomyiidae) is an important pest of young apple trees in New Zealand and a serious quarantine pest in Asia, Australia, and western United States. Platygaster demades Walker (Hymenoptera: Platygastridae) is a parasitoid of D. mali. The developmental period of the parasitoid is longer than that of D. mail, suggesting a possible asynchrony between the two species in the field. Prior to the present study, this parasitoid was considered laying eggs only in the host eggs. Here we carried out experiments in the laboratory and field to determine whether P. demades also parasitized other stages of the host and explain the recently observed high parasitism rate and parasitoid-host synchronization in the field. We demonstrated for the first time that P. demades explored and accepted both eggs and first-instar larvae of D. mali as hosts. This feature widens the phenological window for parasitization, allowing the parasitoid to continue laying eggs after D. mali eggs hatch, and contributes to the high within- and between-generation parasitism rate and synchronization of the two species. Therefore, the difference in developmental period between the pest and its parasitoid cannot simply be considered evidence of asynchrony between the two. The consistent superparasitism rate and progeny sex ratio regardless of host stage at parasitization detected in the present study may be attributed to the fact that P. demades eggs do not hatch until the host larvae reach the third instar (mature) and thus all parasitoid larvae feed on the third-instar larvae with similar quantity and quality of nutrition. The higher parasitism rate in eggs than in larvae may be due to higher larval defense ability against attack by and lower attractiveness to the parasitoid., (© The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The Asian citrus psyllid, Diaphorina citri Kuwayama, is an important pest in Florida because it transmits bacteria responsible for citrus huanglongbing disease. In addition to infesting citrus, orange jasmine (Murraya exotica L.) is one of Asian citrus psyllid's preferred host plants and is widely grown as an ornamental hedge. We report on Asian citrus psyllid bionomics over three years at five urban plantings of orange jasmine and on biological control of Asian citrus psyllid by a parasitoid Tamarixia radiata (Waterston). T. radiata had been released in Florida shortly after Asian citrus psyllid was first found, and the parasitoid was known to be established at each planting. Additionally, three new T. radiata haplotypes were released every 3 wk at three plantings during the first study year (one haplotype per planting, over all releases an average of 17 parasitoids per linear meter of hedge); all three haplotypes were released at a fourth planting beginning midway through the study (over all releases, an average combined total of 202 parasitoids per linear meter of hedge). Asian citrus psyllid populations were present year-round at each planting, often at large levels. Such plantings may pose risk to commercial citrus as Asian citrus psyllid reservoirs. Releases of the new haplotypes did not cause any measurable reduction in Asian citrus psyllid population levels during the study, and ironically percentage parasitism was generally highest at a planting where no releases were made. Higher release rates might have been more effective. The probability is discussed that repetitive pruning of orange jasmine reduced the full potential of T. radiata against Asian citrus psyllid in this study., (Published by Oxford University Press on behalf of Entomological Society of America 2015. This work is written by US Government employees and is in the public domain in the US.)

Pod borers are economically important soybean pests in temperate and tropical regions. However, the biological control of these pests using their natural insect enemies has been poorly studied to date. Indigenous natural populations of three Trichogramma (Hymenoptera: Trichogrammatidae) species, Trichogramma chilonis Ishii, Trichogramma ostriniae Pang & Chen, and Trichogramma leucaniae Pang & Chen, were collected from Leguminivora glycinivorella (Matsumura) (Lepidoptera: Tortricidae) eggs in soybean fields in China. In this study, we compare the parasitic capacities and suitabilities of three indigenous Trichogramma species on L. glycinivorella eggs at various ages. Host eggs of all ages were accepted by T. chilonis, T. ostriniae, and T. leucaniae. T. chilonis tended to parasitize 0-2-d-old eggs more than 3-4-d-old eggs. There were no significant differences in parasitism between the 0-2-d-old eggs and the 1-4-d-old eggs for T. ostriniae and T. leucaniae. For eggs at various ages, T. chilonis parasitized the smallest number of eggs, while T. leucaniae and T. ostriniae exhibited similar parasitic capacities. With 0-d-old host eggs, T. ostriniae developed over the longest time period (8.7 d), and T. leucaniae produced the most female progeny (87.9%). Both T. leucaniae and T. ostriniae had similar developmental times, survival rates and percentages of female progeny with 1-3-d-old eggs. These results show that T. leucaniae can parasitize host eggs at varying ages with the best development and suggest that it may be a valuable biological control agent for soybean pod borers., (© The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

The bean bug, Riptortus pedestris (F.) (Hemiptera: Alydidae) is one of the most important pests of soybean (Glycine max L. Merrill) in Korea and Japan. R. pedestris is known to appear early in spring when leguminous seeds such as soybean are not available. Because soybean has been reported to be the most important food source for R. pedestris development, in this study, we assessed the effect of this period of soybean deprivation during the nymphal stage on the development and reproduction of R. pedestris and on egg parasitism by its two egg parasitoids. More than 50% of the R. pedestris population tested survived on barley, even when they did not start feeding on soybean until the fourth instar. Nevertheless, R. pedestris nymphs deprived of soybean developed more slowly and became smaller adults than those provided with soybean. However, no difference was observed in the preovipositional period or fecundity between these groups. In addition, neither the hatch nor the egg parasitism rate by two egg parasitoids was affected by the presence or absence of soybeans in the nymphal diet. This study indicates that R. pedestris nymphs can develop successfully even when lacking this important food source in early life, and that adult reproduction is not affected by the quality of diet ingested during the nymphal period., (© 2014 Entomological Society of America.)

Trichogramma species and strains differ significantly in host specificity and performance. Nine Trichogramma strains, six of them collected from paddy fields in the Greater Mekong Subregion, were evaluated for performance on eggs of the striped stem borer, Chilo suppressalis (Walker), in both laboratory and field tests to determine potential Trichogramma strains that can be used in an inundative release in an integrated pest management program. In the laboratory glass vial tests, all strains showed higher parasitism rates on 0-24-h eggs than on the two older age groups (24-48 and 48-72 h). Wasp emergence rate was also higher from parasitized 0-24-h striped stem borer eggs, while Trichogramma immature duration was significantly prolonged on 0-24-h striped stem borer eggs. Parasitism rates differed among Trichogramma strains, with Trichogramma chilonis Ishii CJ strain showing significantly higher parasitism rate than any other strains. In the field tests, parasitism of sentinel striped stem borer eggs by Trichogramma strains released at 50,000, 100,000, and 200,000 wasps per hectare was low, with marginal yet significant differences between strains. The highest parasitism was achieved by T. chilonis CJ strain at the high and medium release rates. Hence, it can be concluded that T. chilonis CJ strain released at 100,000 wasps per hectare may be a cost-effective control tactic for field releases targeting striped stem borer.

The South American tomato leafminer, Tuta absoluta Meyrick (Lepidoptera: Gelechiidae), is a major pest that has recently invaded Afro-Eurasia. Biological control, especially by Trichogramma parasitoids, is considered to be promising as a management tool for this pest. However, further development of Trichogramma-based biocontrol strategies would benefit from assessing the impact of released parasitoid offspring on the pest. Under laboratory conditions, we 1) compared the parasitism of five Trichogramma species-strains on the pest-plant system T. absoluta-tomato, and 2) assessed various biological traits of parasitoids, mass-reared on a factitious host (Ephestia kuehniella Zeller), when developing on T. absoluta. In addition, we evaluated the overall efficiency of two specific Trichogramma species when released under greenhouse conditions in combination with a common natural enemy in tomato crop, the predator Macrolophus pygmaeus Rambur. Parasitoids emerging from T. absoluta on tomato showed lower parasitism rates and poor biological traits, for example, wing deformations, reduced longevity, when compared with the control reared on the factitious host. Under greenhouse conditions, the parasitoids that developed on T. absoluta after initial releases contributed little to biological control of T. absoluta, and parasitism tended to be lower when the predator was present. However, a slightly higher T. absoluta control level was achieved by combining the predator and release of the parasitoid Trichogramma achaeae Nagaraja and Nagarkatti. This study shows that Trichogramma parasitoids may not build up populations on the T. absoluta-tomato system, but that Trichogramma parasitoids can be used in combination with M. pygmaeus to enhance biological control of the pest in tomato crops.

The aggregation pheromone of Riptortus pedestris (F.) (Hemiptera: Alydidae) is known to attract its egg parasitoids Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae) and Gryon japonicum (Ashmead) (Hymenoptera: Scelionidae). Distribution and composition of these egg parasitoids were compared in a soybean field in the presence and absence of aggregation pheromone-baited traps for two consecutive years. Three traps were installed on the edge of a soybean field, first without and then with aggregation pheromone in a before-after design, and changes in parasitism were assessed on nonviable host eggs released at distances of 9, 18, 27, and 36 m from the trap. A significant interactive effect of pheromone installation and distance was found in egg parasitism by both parasitoids. Parasitism on eggs recovered from 9 m away was up to 2.2 and 3.2 times higher in presence of pheromone than without pheromone for O. nezarae and G. japonicum, respectively. Parasitism by O. nezarae was always higher than that by G. japonicum, but their relative abundance, clutch size, and sex ratio were not affected by pheromone installation, irrespective of distance from the trap. In conclusion, aggregation pheromone increases abundance of parasitoids up to 18 m from trap installation points and does not affect the relative abundance of parasitoid species.

The aim of the study was to investigate the attractiveness to herbivores and parasitoids of two cultivars of Brassica oleracea L., namely, B. oleracea variety acephala (kale) and B. oleracea variety capitata (cabbage), that exhibit differences of morphological and biochemical traits. To this end, field samplings were replicated at seven localities in Galicia (northwestern Spain). Three specialist and three generalist lepidopteran species were sampled. In total, 7,050 parasitoids were obtained, belonging to 18 genera and 22 species. The results showed that 1) parasitism rate and parasitoid species richness changed with locality and was higher in cabbage, although this crop had lower herbivore abundance; 2) the proportion of specialist herbivores was higher in cabbage crops, whereas generalists dominated in kale crops; 3) the abundance of the parasitoids Telenomus sp. (Hymenoptera, Scelionidae), Cotesia glomerata L. (Hymenoptera: Braconidae), and Diadegma fenestrale (Holmgren) (Hymenoptera: Ichneumonidae) was higher in kale crops; and 4) parasitism rate of Pieris rapae larvae and pupae and Mamestra brassicae eggs were higher in kale crops. In contrast with the notion that plant structural complexity provides physical refuge to the hosts and can interfere with parasitoid foraging, parasitism rate was higher on cabbage plants, which form heads of overlapped leaves. Possibly, different chemical profiles of cultivars also influenced the host-parasitoid relationship. These results suggest that top-down and bottom-up forces may enhance cabbage crops to better control herbivore pressure during the studied season. In Spain, information on natural occurring parasitoid guilds of Brassica crops is still scarce. The data provided here also represent a critical first step for conservation biological control plans of these cultivations.

The parasitoid Trichogramma confusum Viggiani (Hymenoptera: Trichogrammatidae) is an important natural enemy of many lepidopterans throughout the world. Extensive toxicological tests have clarified the toxic effects of insecticides on trichogrammatids, but only few studies have examined these effects on T. confusum. Among the seven classes of tested chemicals, organophosphates and carbamates exhibited the highest intrinsic toxicity to the parasitoid with LC50 values ranging from 0.037 (0.030-0.046) to 0.29 (0.23-0.38) and from 0.17 (0.15-0.19) to 1.61 (1.45-1.79) mg AI L(-1), respectively. They were followed by phenylpyrazoles, avermectins, pyrethroids, and neonicotinoids, which induced variable toxicity responses with LC50 values ranging from 0.63 to 45.26, 1.06-21.73, 3.89-19.36, and 0.24-754.2 mg AI L(-1), respectively. In contrast, insect growth regulators (IGRs) showed the least toxicity to the parasitoid with LC50 values ranging from 3,907 (3,432-4,531) to 10,154 (8,857-12,143) mg AI L(-1). A risk quotient analysis indicated that neonicotinoids (except thiamethoxam), avermectins, pyrethroids, IGRs, and phenylpyrazoles are safe, but organophosphates and carbamates are slightly to moderately or dangerously toxic to T. confusum. This study provides informative data for implementing both biological and chemical control strategies in integrated pest management of lepidopterans.

Pseudoligosita plebeia (Perkins) (Hymenoptera: Trichogrammatidae) is a candidate biological control agent targeting the glassy-winged sharpshooter, Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), in California. Little is known about the biology of P. plebeia. Here we report the results of laboratory studies describing the longevity of P. plebeia adults provided alternative food resources, their ability to parasitize H. vitripennis eggs of different ages, lifetime offspring production when provided steady access to excess host eggs, and levels of mature ovarian eggs present when wasps were held without access to hosts. P. plebeia is a gregarious parasitoid, with up to six adults emerging from a single H. vitripennis egg. When provided with honey and water, water alone, or no food or water, P. plebeia adult females lived an average of 64.1, 2.3, and 2.0 d, respectively. P. plebeia were able to successfully parasitize all ages of H. vitripennis eggs (1-8 d old), with higher parasitism in younger host eggs (1-3 d old) than in older host eggs (5-7 d old). An increasing trend in offspring production was seen for P. plebeia from adult age 2-26 d followed by a decreasing trend with offspring produced up to age 75 d. P. plebeia females are at least partially synovigenic, as they contained fewer mature eggs at younger ages (1 and 3 d old) than at older ages (5, 11, 15, and 31 d old). Our results provide foundational information regarding the biology of P. plebeia useful for its further evaluation as a potential biological control agent in California.

The objective of this study was to evaluate the potential of Aprostocetus hagenowii (Ratzeburg) (Hymenoptera: Eulophidae) to control American cockroaches, Periplaneta americana (L.) (Dictyoptera: Blattidae), in sewer manholes and in crevices around buildings. Parasitoids were released weekly for 12 wk from laboratory parasitized heat-killed oothecae, and parasitism monitored using sentinel oothecae of American cockroaches. In addition, preference of A. hagenowii for 1- to 4-wk-old oothecae was evaluated in the laboratory. A. hagenowii females showed no preference for any ootheca age. Twenty of the 30 tested females parasitized one ootheca, whereas the other 10 parasitized two oothecae. The total progeny (males, females, and total) that emerged from a single ootheca parasitized by a female was not significantly different to the total progeny that emerged from two oothecae parasitized by a female. The number of males, females, and total progeny that emerged from the second parasitized ootheca was significantly less than the number that emerged from the first parasitized ootheca. The weekly mean sentinel oothecal parasitism rate in wall crevices was 18.1 +/- 3.2% and in sewer manholes was 13.3 +/- 2.0%. The mean number of released A. hagenowii females per number of parasitized sentinel oothecae recorded in crevices was 189 +/- 18, whereas it was 428 +/- 50 in sewers. A. hagenowii females were more effective at parasitizing sentinel oothecae placed at high and middle levels in manholes than at a low level when releases were made at the midpoint of the manhole shaft.

Riptortus pedestris (F.) (Hemiptera: Alydidae) is a key pest of soybean [Glycine max (L.) Merr.] in Korea and Japan. Aggregation pheromone traps have been used to attract R. pedestris. An aggregation pheromone, produced by males of R. pedestris, also attracts the egg parasitoid, Ooencyrtus nezarae Ishii (Hymenoptera: Encyrtidae). As a new method of pest management, we propose the use of nonviable host eggs in the pheromone trap together to both trap R. pedestris and propagate parasitoids on host eggs attached to the trap. Approximately ten-thousand nonviable refrigerated host eggs were placed outside pheromone traps in three soybean fields (0.167-0.284 ha.). During the sampling period from 7 August to 8 October in 2008, statistical significance of treatment was not found in any life stage of R. pedestris population. However, significantly higher parasitism of both natural (78-91%) and refrigerated eggs (36-59%) occurred in the treatment sites, compared with control sites where parasitism was 0-62% and 16-34% on natural and refrigerated eggs, respectively. The proportion of bean pods with stink bug feeding damage was significantly reduced by 47% in the treatment sites. This study is the first trial of an integrated pest management (IPM) strategy using both nonviable host eggs and trap that simultaneously targets both the pest and its natural enemy.

Brown stink bug, Euschistus servus (Say), and green stink bug, Acrosternum hilare (Say) (Hemiptera: Pentatomidae), are major agricultural pests. Although various insecticides are used to control nymphs and adults, little is known about how they affect eggs. Laboratory bioassays and field trials were conducted to determine the efficacy of common field rates of acephate, lamda-cyhalothrin, spinosad, and thiamethoxam on developing E. servus and A. hilare eggs, as well as Telenomus podisi Ashmead (Hymenoptera: Scelionidae) parasitoids developing in E. servus eggs. In laboratory bioassays, egg masses were dipped into insecticide and water solutions and assessed for mortality after 2 wk. In the field trials, egg masses on a cloth section were pinned to leaves in each plot ofa randomized complete block and returned to the laboratory 24 h after exposure to insecticide sprays. Mortality was assessed after 2 wk. In dip bioassays, there was a significant effect of insecticide treatment on A. hilare eggs with all insecticides resulting in greater mortality than the water control. However, no effect of treatment occurred in the field with A. hilare or for E. serous eggs in both the laboratory bioassays and the field trials. In contrast, developing T. podisi parasitoids showed significant mortality when exposed to all insecticide treatments, when dipped or field-treated. Spinosad and lamda-cyhalothrin treatments resulted in 100% mortality of T. podisi, and acephate resulted in greater mortality than thiamethoxam. Our results suggest that there is relatively little efficacy from insecticide sprays on stink bugs developing in eggs but that mortality of egg parasitoids may be significant.

This study assessed the effects of refrigerated storage on the suitability of eggs of the glassy-winged sharpshooter, Homalodisca coagulata (Say) (Hemiptera: Cicadellidae), as hosts for propagation of the parasitoid Gonatocerus ashmeadi Girault (Hymenoptera: Mymaridae). Development of the host eggs was terminated by chilling at 2 degrees C for 5 d before storage was initiated at 10 degresC for up to 70 d. Parasitism, adult emergence rate, developmental time, and sex ratio were used to gauge the suitability of the eggs as hosts after storage. In addition to these measures, demographic growth parameters also were used to assess the quality of the wasp progeny through the F2 generation. Host eggs stored 20 d remained fully acceptable to the wasps for attack. Although the parasitism rate decreased with storage time, > 80% adult parasitoid emergence was realized from eggs stored 30 d. After 70 d storage, adult emergence rate was decreased by 48%, fecundity decreased by 53%, female production by 19%, developmental time was extended 3 d, and female longevity was shortened 5 d. The emergence pattern of F1 but not F2 adults varied with storage time of the parental and grandparental hosts, respectively. For the F1 generation, emergence rate, development, and sex ratio did not vary with storage time when the F1 parents parasitized fresh host eggs. Demographic parameters for the F, population showed that net reproductive rate was > 20 although it decreased significantly after their parental host eggs were stored for > 30 d. The intrinsic and finite rates of increase, population doubling time, and mean generation time decreased only after storage for 60 d. Our results show that short-term cold storage could be used for maintaining wasp populations in a mass-rearing program and that the detrimental effects of chilling host eggs in storage for over 30 d do not extend to F2 generation.

The effects of shelving type, packaging, and release height on success of Trichogramma deion Pinto & Oatman (Hymenoptera: Trichogrammatidae) parasitizing Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) eggs was studied under laboratory conditions. In trials on multipletiered gondola-type or open shelving units, with or without packaging, foraging success was evaluated by comparing parasitism and total mortality rates of sentinel egg disks among shelves after a single point-release of T. deion. Results showed that T. deion parasitized more egg disks and killed more total eggs on open shelves than on gondola shelving. The presence of packaging had no effect on parasitoid foraging on open shelves; however, packaging did interfere with parasitism of P. interpunctella eggs on gondola shelving. Egg parasitism and mortality patterns among shelves were not as evenly distributed on gondola-type shelving compared with open shelving. On gondola shelves without packages, changing the release point of T. deion from the middle to the lowest shelf shifted the distribution of parasitism toward the floor. Gondola shelving, especially in the presence of packaging, reduced foraging efficiency of T. deion for P. interpunctella eggs. Thus, to attain adequate control of P. interpunctella, it may be necessary to use two release heights on gondola shelving.

As growers switch to transgenic crops and selective insecticides that are less toxic to natural enemies, natural enemies can become more important in agricultural pest management. Current decision-making guides are generally based on pest abundance and do not address pest and natural enemy toxicity differences among insecticides or the impact of natural enemies on pest survival. A refined approach to making pest management decisions is to include the impact of natural enemies and insecticides, thereby better integrating biological and chemical control. The result of this integration is a dynamic threshold that varies for each product and the level of biological control expected. To demonstrate the significance of conserved biological control in commercial production, a decision-making guide was developed that evaluates control options for European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), in sweet corn, Zea mays L., where the primary natural enemies are generalist predators. Management options are lambda-cyhalothrin (broad-spectrum insecticide), spinosad (selective insecticide), Trichogramma ostriniae (Peng and Chen) (Hymenoptera: Trichogrammatidae) (parasitoid), and Bacillus thuringiensis (Bt) sweet corn (transgenic variety). The key factors influencing thresholds for all treatments are the intended market, predator populations, and the presence of alternative foods for the predators. Treatment cost is the primary factor separating the threshold for each treatment within a common scenario, with the lowest cost treatment having the lowest pest threshold. However, when the impact of a treatment on natural enemies is projected over the 3-wk control period, the impact of the treatment on predators becomes the key factor in determining the threshold, so the lowest thresholds are for broad-spectrum treatments, whereas selective products can have thresholds > 6 times higher by the third week. This decision guide can serve as a framework to help focus future integrated pest management research and to aid in the selection of pest management tools.

Biological control using hymenopteran parasitoids presents an attractive alternative to insecticides for reducing infestations and damage from the Indianmeal moth, Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae), in retail and warehouse environments. We examined the potential for using combinations of the egg parasitoid Trichogramma deion Riley (Hymenoptera: Trichogrammatidae), and the larval parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) for preventing infestations of P. interpunctella in coarse-ground cornmeal as well as the influence of packaging on parasitoid effectiveness. Treatments included one or both parasitoids and either cornmeal infested with P. interpunctella eggs or eggs deposited on the surface of plastic bags containing cornmeal. H. hebetor had a significant impact on the number of live P. interpunctella, suppressing populations by approximately 71% in both unbagged and bagged cornmeal. In contrast, T. deion did not suppress P. interpunctella in unbagged cornmeal. However, when released on bagged cornmeal, T. deion significantly increased the level of pest suppression (87%) over bagging alone (15%). When H. hebetor was added to bagged cornmeal, there was a significant reduction of live P. interpunctella compared with the control (70.6%), with a further reduction observed when T. deion was added (96.7%). These findings suggest that, in most situations, a combined release of both T. deion and H. hebetor would have the greatest impact; because even though packaging may protect most of the stored products, there are usually areas in the storage landscape where poor sanitation is present.