Optimizing the releasing strategy used for the biological control of the sugarcane borer Diatraea saccharalis by Trichogramma galloi with computer modeling and simulation.

One of the challenges in augmentative biological control programs is the definition of releasing strategy for natural enemies, especially when macro-organisms are involved. Important information about the density of insects to be released and frequency of releases usually requires a great number of experiments, which implies time and space that are not always readily available. In order to provide science-based responses for these questions, computational models offer an in silico option to simulate different biocontrol agent releasing scenarios. This allows decision-makers to focus their efforts to more feasible options. The major insect pest in sugarcane crops is the sugarcane borer Diatraea saccharalis, which can be managed using the egg parasitoid Trichogramma galloi. The current strategy consists in releasing 50,000 insects per hectare for each release, in three weekly releases. Here, we present a simulation model to check whether this releasing strategy is optimal against the sugarcane borer. A sensitive analysis revealed that the population of the pest is more affected by the number of releases rather than by the density of parasitoids released. Only the number of releases demonstrated an ability to drive the population curve of the pest towards a negative growth. For example, releasing a total of 600,000 insects per hectare in three releases led to a lower pest control efficacy that releasing only 250,000 insects per hectare in five releases. A higher number of releases covers a wider range of time, increasing the likelihood of releasing parasitoids at the correct time given that the egg stage is short. Based on these results, it is suggested that, if modifications to the releasing strategy are desired, increasing the number of releases from 3 to 5 at weekly intervals is most likely preferable.

Season and herbivore defence trait mediate tri-trophic interactions in tropical rainforest.

Bottom-up effects from host plants and top-down effects from predators on herbivore abundance and distribution vary with physical environment, plant chemistry, predator and herbivore trait and diversity. Tri-trophic interactions in tropical ecosystems may follow different patterns from temperate ecosystems due to differences in above abiotic and biotic conditions. We sampled leaf-chewing larvae of Lepidoptera (caterpillars) from a dominant host tree species in a seasonal rainforest in Southwest China. We reared out parasitoids and grouped herbivores based on their diet preferences, feeding habits and defence mechanisms. We compared caterpillar abundance with leaf numbers ('bottom-up' effects) and parasitoid abundance ('top-down' effects) between different seasons and herbivore traits. We found bottom-up effects were stronger than top-down effects. Both bottom-up and top-down effects were stronger in the dry season than in the wet season, which were driven by polyphagous rare species and host plant phenology. Contrary to our predictions, herbivore traits did not influence differences in the bottom-up or top-down effects except for stronger top-down effects for shelter-builders. Our study shows season is the main predictor of the bottom-up and top-down effects in the tropics and highlights the complexity of these interactions.

A peculiar case of parasitisation with two new species of wasps parasitizing the rice leaf-roller Pelopidas mathias (Fabricius, 1798) (Lepidoptera: Hesperiidae) from southern India.

Paddy, Oryza sativa L. (Poales: Poaecea) is infested by a series of lepidopteran, coleopteran, hemipteran, and acarine pests in India. Of the long list, the species Rice Leaf-Roller Pelopidas mathias (Fabricius, 1798) (Lepidoptera: Hesperiidae) is one of most encountered defoliators on paddy. Here we record and describe with illustrations, a new parasitic complex comprising of two new species of parasitic wasps, viz. Brachymeria eastwoodi Binoy, sp. nov. and Sympiesis eastwoodi James & Santhosh, sp. nov. on the pupae of P. mathias from southern India. The parasitoid complexes on P. mathias are also augmented.

TARANTOBELUS JEFFDANIELSI N. SP. (PANAGROLAIMOMORPHA; PANAGROLAIMIDAE), A NEMATODE PARASITE OF TARANTULAS.

Multiple tarantula deaths for a wholesale breeder were reported in 2018. The breeder noticed white discharge in the oral cavities of the tarantulas. Upon inspection, it was discovered that the white discharge was a large group of nematodes intertwined inside the tarantula's oral cavity. We examined the nematodes and propose a new species, Tarantobelus jeffdanielsi n. sp., in the currently monotypic genus Tarantobelus based on a combination of morphological and morphometrical data and unique nuclear rDNA 28S and 18S sequences. Based on phylogenetic analyses, the previously described Tarantobelus arachnicida was relocated, along with T. jeffdanielsi, into the family Panagrolaimidae. We also provide evidence of the ability of T. jeffdanielsi to parasitize Galleria mellonella larvae and the tarantula Grammostola pulchra. The life span and fecundity of the new species were also assessed, resulting in an 11.2-d average life span, and a total fertility rate of 158 nematodes/adult.

Combination of generalist predators, Nesidiocoris tenuis and Macrolophus pygmaeus, with a companion plant, Sesamum indicum: What benefit for biological control of Tuta absoluta?

Tuta absoluta is one of the most damaging pests of tomato crops worldwide. Damage due to larvae may cause up to 100% loss of tomato production. Use of natural enemies to control the pest, notably predatory mirids such as Nesidiocoris tenuis and Macrolophus pygmaeus, is increasingly being promoted. However, considering the potential damage caused to tomatoes by these omnivorous predators in the absence of T. absoluta, an alternative solution could be required to reduce tomato damage and improve the predators' performance. The use of companion plants can be an innovative solution to cope with these issues. The present study aimed to determine the influence of companion plants and alternative preys on the predators' performance in controlling T. absoluta and protecting tomato plants. We evaluated the effect of predators (alone or combined) and a companion plant (sesame (Sesamum indicum)) on T. absoluta egg predation and crop damage caused by N. tenuis. The influence of an alternative prey (Ephestia kuehniella eggs) on the spatial distribution of predators was also evaluated by caging them in the prey presence or absence, either on tomato or sesame plants or on both. We found that the presence of sesame did not reduce the efficacy of N. tenuis or M. pygmaeus in consuming T. absoluta eggs; hatched egg proportion decreased when N. tenuis, M. pygmaeus, or both predators were present. More specifically, this proportion was more strongly reduced when both predators were combined. Sesame presence also reduced necrotic rings caused by N. tenuis on tomato plants. Nesidiocoris tenuis preferred sesame over tomato plants (except when food was provided only on the tomato plant) and the upper part of the plants, whereas M. pygmaeus preferred tomato to sesame plants (except when food was provided only on the sesame plant) and had no preference for a plant part. Combination of predators N. tenuis and M. pygmaeus allows for better coverage of cultivated plants in terms of occupation of different plant parts and better regulation of T. absoluta populations. Sesamum indicum is a potential companion plant that can be used to significantly reduce N. tenuis damage to tomatoes.

Performance of Trichogramma japonicum under field conditions as a function of the factitious host species used for mass rearing.

Different factitious hosts were used to mass rear Trichogramma japonicum Ashmead in different parts of the globe because thorough details were lacking in both the laboratory and the field. The objective of this study was to compare, parasitoid, T. japonicum reared in different factitious hosts. Three commonly used factitious host eggs, Corcyra cephalonica (Stainton), Ephestia kuehniella Zeller and Sitotroga cerealella Olivier were tested under laboratory conditions and then in the field over a yellow stem borer, Scirpophaga incertulus (Walker) of rice. The highest parasitism by T. japonicum was observed on E. kuehniella eggs. The parasitoid's highest emergence (88.99%) was observed on S. cerealella eggs at 24 h exposure, whereas at 48 h it was on E. kuehniella eggs (94.66%). Trichogramma japonicum females that emerged from E. kuehniella eggs were significantly long-lived. The days of oviposition by hosts and the host species were significant individually, but not their interaction. Higher proportions of flying T. japonicum were observed when reared on E. kuehniella and C. cephalonica eggs. Field results showed that T. japonicum mass-reared on E. kuehniella showed higher parasitism of its natural host, S. incertulus eggs. Hence, by considering these biological characteristics and field results, E. kuehniella could be leveraged for the mass rearing of quality parasitoids of T. japonicum in India, the Asian continent and beyond.

Horizontally transmitted parasitoid killing factor shapes insect defense to parasitoids.

Interkingdom competition occurs between hymenopteran parasitoids and insect viruses sharing the same insect hosts. It has been assumed that parasitoid larvae die with the death of the infected host or as result of competition for host resources. Here we describe a gene family, parasitoid killing factor (pkf), that encodes proteins toxic to parasitoids of the Microgastrinae group and determines parasitism success. Pkfs are found in several entomopathogenic DNA virus families and in some lepidopteran genomes. We provide evidence of equivalent and specific toxicity against endoparasites for PKFs found in entomopoxvirus, ascovirus, baculovirus, and Lepidoptera through a mechanism that elicits apoptosis in the cells of susceptible parasitoids. This highlights the evolutionary arms race between parasitoids, viruses, and their insect hosts.

Cold storage-mediated rearing of Trichogramma evanescens Westwood on eggs of Plodia interpunctella (Hübner) and Galleria mellonella L.

The egg parasitoid Trichogramma evanescens Westwood is considered as an efficient biological control agent for managing several lepidopteran pests and it is widely distributed throughout the world. Mass rearing protocols of parasitoids that are currently in use in biocontrol programs require a meticulous quality control plan, in order to optimize their efficacy, but also their progeny production capacity. In this paper, the effect of different factors on the quality control in mass rearing of T. evenescens, using Plodia interpunctella (Hübner) and Galleria mellonella L. as host species, were investigated. The impact of egg agewas significant in the rates of parasitism, for both host species tested. Significantly highest percent of parasitoid emergence was noticed in two day-old eggs for both host species, while one day-old eggs day exhibited the maximum emergence when both species were used togetherin the same trials. Age-dependent storage egg preservation at either 4 or 9°C significantly influenced the parasitism percentages on both species. The highest parasitism percentage was recorded in two day-old G. mellonella eggs that are kept for 15 days at 9°C while the lower in one day-old P. interpunctella eggs for 60 d storage. Moreover, the highest parasitoid mortality was recorded in T. evanescens reared either on P. interpunctella or G. mellonella at 20°C. Rearing of the parasitoid on a mixture of eggs of both host species resulted in higher parasitism, but not always in higher rates of parasitoid emergence. The results of the present work provide useful information that can be further utilized in rearing protocols of T. evanescens.

Analysis of the Glyphodes pyloalis larvae immune transcriptome in response to parasitization by its endoparasitoid, Aulacococentrum confusum.

The interaction between a host and its parasitoid is one of the most fascinating relationships of insects. Immune-related genes play crucial roles in this association. Nevertheless, until now, identification of these genes on a large scale has not received much attention. To gain insight into the parasitic effects of the endoparasitoid Aulacocentrum confusum (Hymenoptera: Braconidae) on Glyphodes pyloalis (Lepidoptera: Pyralidae) larva, which is a destructive pest of mulberry (Morus alba L.) trees in China, we presented a transcriptome dataset for uncovering immune-related genes in parasitized G. pyloalis larvae. In total, 91,118,138 and 92,778,814 clean reads were obtained from parasitized and healthy host larvae, respectively, and de novo assembly generated 57,122 unigenes. The transcriptional profile of G. pyloalis larvae was remarkably influenced by parasitism. A total of 3259 differentially expressed genes (DEGs) were identified in parasitized and nonparasitized G. pyloalis larvae and 55 genes related to immune response were screened from these DEGs. Among the 55 DEGs, 37 genes were significantly upregulated, and 18 genes were downregulated. qRT-PCR validated the sequencing results and revealed that the expression levels of selected immune-related genes depended on the parasitization and duration after parasitization. Knocking down the C type lectin gene (CTL) changed the expression of serine proteinase, serine protease inhibitor, antimicrobial peptide, prophenoloxidase activating enzymes and peroxiredoxin in G. pyloalis larvae, suggesting CTL can modulate the immune response after parasitization by A. confusum females. The present study provides a foundation for revealing the molecular mechanisms of immune response in G. pyloalis larvae when they are parasitized by A. confusum and promotes the development of novel biological control practices for G. pyloalis.

Insect Immune Evasion by Dauer and Nondauer Entomopathogenic Nematodes.

The immune response of animals, including insects, is overcome by some parasites. For example, dauer larvae (DL) of the obligate entomopathogenic nematodes (EPNs) Heterorhabditis and Steinernema can invade insects, evade their defenses, and cause death. Although DL were long assumed to be the only infective stage of nematodes, recent reports suggest that L2-L3 larvae of facultative EPNs are also capable of killing insects. There are no studies, to our knowledge, about the role of nonimmunological barriers (the exoskeleton and its openings) in avoiding infection by DL and L2-L3 larvae, or whether these larval stages evade the host immune system in the same way. The objective of this study was to examine these questions by infecting Galleria mellonella with the facultative parasitic nematode Rhabditis regina. DL or L2-L3 larvae were either deposited on or near the moths or injected into their hemocoel. Once nematodes reached the hemocoel, the following host immune response parameters were quantified: prophenoloxidase, phenoloxidase, lytic activity, and the number of granular hemocytes. DL showed a greater ability to penetrate the exoskeleton than L2-L3 larvae. Once inside, however, both went unnoticed by the immune system and killed the insect. A higher number of granular hemocytes was activated by L2-L3 larvae than DL. We show for the first time that L2-L3 larvae can penetrate and evade the insect immune system. Further research is needed to compare facultative and specialized EPNs to determine which is more likely, with both DL and L2-L3 larvae, to evade insect defense barriers and produce death. The results will contribute to understanding the evolution of virulence in entomopathogenic nematodes.

Tetrastichus howardi (Hymenoptera: Eulophidae): first report of parasitism in Oxydia vesulia (Lepidoptera: Geometridae) / Tetrastichus howardi (Hymenoptera: Eulophidae): primeiro relato de parasitismo em Oxydia vesulia (Lepidoptera: Geometridae)

The adaptation of native lepidopteran species to eucalyptus plantations reduces the productivity of this crop in Brazil. Oxydia vesulia Cramer (Lepidoptera: Geometridae) is a secondary pest, frequently reported in eucalyptus plantations with population outbreaks and economic damages. Methods of biological control of this pest may include the use of the exotic pupae endoparasitoid Tetrastichus howardi Olliff (Hymenoptera: Eulophidae), reported as efficient to controlling lepidopteran pests. The parasitism of O. vesulia caterpillars and pupae by T. howardi was evaluated under controlled conditions (25 ± 1 ºC, 60 ± 20% humidity and 12:12 h L:D). Each O. vesulia caterpillar or pupae was individually placed in a flat-bottom tube with 10 and 15 females of T. howardi for 48h, respectively. The parasitoids were removed after that period, the caterpillars were fed and the pupae were maintained until emergence of the parasitoid or formation of pupae and emergence of adults of this pest. The fourth-instar caterpillars of O. vesulia, after the parasitism period, were kept in pots with Eucalyptus urophylla leaves, changed daily until the end of the experiment. A total of 40% of the caterpillars died before the pre-pupae stage, 40% reached the pupae stage and died due to inadequate adult formation and 20% generated moths, but none adult parasitoid emerged from the caterpillars. All pupae of O. vesulia were parasitized and showed emergence of parasitoids. The parasitism of O. vesulia caterpillars and pupae by T. howardi shows the potential of this natural enemy for the integrated management of this defoliator pest in eucalyptus plantations.

A adaptação de espécies nativas de lepidópteros a plantios de eucalipto reduz a produtividade dessa cultura no Brasil. Oxydia vesulia Cramer (Lepidoptera: Geometridae) é praga-secundária, frequentemente, relatada em plantios de eucalipto com surtos populacionais e danos econômicos. Métodos de controle biológico, dessa praga, podem incluir o uso do endoparasitoide exótico de pupas Tetrastichus howardi Olliff (Hymenoptera: Eulophidae) relatado como eficiente para o controle de lepidópteros-pragas. O parasitismo de lagartas e pupas de O. vesulia por T. howardi foi avaliado em condições controladas (25 ± 1º C, 60 ± 20% umidade e 12h fotoperíodo). Cada lagarta ou pupa de O. vesulia foi colocada individualmente em tubos de fundo chato com 10 e 15 fêmeas de T. howardi por 48h, respectivamente e, após esse período, os parasitoides foram removidos, as lagartas alimentadas e as pupas mantidas até a emergência do parasitoide ou formação de pupas ou de adultos dessa praga. As lagartas de quarto ínstar de O. vesulia, após o período de parasitismo, foram mantidas em potes com folhas de Eucalyptus urophylla trocadas, diariamente, até o fim do experimento. Um total de 40% das lagartas de O. vesulia morreu antes da fase de pré-pupa, 40% atingiram o estágio de pupa e morreram devido à má formação ou problemas e 20% originaram mariposas, porém nenhum parasitoide adulto emergiu das lagartas. Todas as pupas de O. vesulia foram parasitadas e tiveram emergência de parasitoides. O parasitismo de lagartas e pupas de O. vesulia por T. howardi mostra o potencial desse inimigo natural para o manejo integrado desse desfolhador em cultivos de eucalipto.

Sistema de vigilancia epidemiológica del lepidopterismo por Hylesia metabus en el Estado Sucre, Venezuela / Epidemiological surveillance system for lepidopterism by Hylesia metabus in Sucre state, Venezuela

Las mariposas (lepidópteros) pueden ocasionar molestias en algunas ocasiones, Hylesia metabuses una mariposa de hábitos nocturnos, caracterizada por presentar pelos que se desprenden durante el vuelo causando dermatitis y diversas reacciones alérgicas (lepidopterismo) en la población. En Venezuela,las invasiones cíclicas de H. metabus en nororiente del país ocasionan un problema de salud pública, requiriendo mantener la vigilancia para orientar labores de control. En este trabajo se realizó una descripción de las actividades para la vigilancia epidemiológica de H. metabus y del lepidopterismo en el estado Sucre. A través de revisión documental, se estudiaron 154 documentos referentes a la vigilancia de H. metabus y del lepidopterismo, emitidos por el Ministerio del Poder Popular para la Salud. Se evidenció una definición clara y precisa de evento, las acciones para el monitoreo de las fases evolutivas de H. metabus se encuentran bien delimitadas; sin embargo, las actividades para el monitoreo de los casos de lepidopterismo no están claramente establecidas. Se observó una adecuada recolección y flujo de información referente alas fases evolutivas de la mariposa, pero poca recolección de datos referentes a los casos de lepidopterismo. El mecanismo del flujo de información estuvo basado en comunicaciones e informes técnicos eventuales y solamente en el nivel estadal de salud se realizó actividades de consolidación y análisis de datos. En conclusión, se encuentran claramente definidas las actividades para el monitoreo de las fases evolutivas de la mariposa, pero deficiencia en la vigilancia del lepidopterismo. Se observan debilidades para la vigilancia epidemiológica de H. metabus(AU)

Butterflies (Lepidoptera) can sometimes cause discomfort, Hylesia metabus is a nocturnal butterfly, characterized by hair shedding during flight causing dermatitis and various allergic reactions (Lepidopterism) in the population. In Venezuela, cyclical invasions of H. metabus in the northeast of the country cause a public health problem, requiring vigilance to guide control efforts. In this work, a description of the activities for the epidemiological surveillance of H. metabus and lepidopterism in Sucre state was made. Through a documentary review, 154 documents referring to the surveillance of H. metabus and lepidopterism, issued by the Ministry of Popular Power for Health, were studied. A clear and precise definition of the event was evidenced, the actions for monitoring the evolutionary phases of H. metabus are well defined; however, activities for the monitoring of lepidopterism cases are not clearly established. There was an adequate collection and flow of information regarding the evolutionary phases of the butterfly, but little data collection regarding the cases of lepidopterism. The information flow mechanism was based on communications and eventual technical reports and only at the state health level were data consolidation and analysis activities carried out. In conclusion, the activities for monitoring the evolutionary phases of the butterfly are clearly defined, but there is a deficiency in the surveillance of lepidopterism. Weaknesses are observed for the epidemiological surveillance of H. metabus(AU)

Infection of canola by the root pathogen Plasmodiophora brassicae increases resistance to aboveground herbivory by bertha armyworm, Mamestra configurata Walker (Lepidoptera: Noctuidae).

Infection of plants by pathogens can result in the upregulation of induced defenses; plants may be more or less susceptible to attack by insect herbivores following infection. We investigated the interaction between canola, Brassica napus L., plants infected with clubroot, Plasmodiophora brassicae Woronin, and a generalist herbivore the bertha armyworm (BAW) Mamestra configurata Walker using two canola cultivars that varied in susceptibility to clubroot disease. Volatile organic compounds released from experimental plants differed with infection and female adult BAW could discriminate between canola plants inoculated with P. brassicae and disease-free plants. Adult female moths preferentially laid eggs on disease-free plants of the susceptible cultivar to P. brassicae. Inoculation of resistant canola with P. brassicae, however, did not influence oviposition by female BAW. The fitness of BAW larvae was reduced when they were reared on susceptible canola inoculated with P. brassicae. Salicylic acid and its conjugates in susceptible canola plants were induced following P. brassicae inoculation as compared to disease-free susceptible plants. We conclude that suppression of BAW oviposition and offspring fitness may result in part from a change in the volatile profile of the plant as a result of inoculation and the induction of defenses in inoculated susceptible canola.

Lipid Dynamics, Identification, and Expression Patterns of Fatty Acid Synthase Genes in an Endoparasitoid, Meteorus pulchricornis (Hymenoptera: Braconidae).

In insect parasitoids, fatty acid synthases (FASs) have received less attention and their roles associated with lipogenesis loss are far from clear. Meteorus pulchricornis is a solitary endoparasitoid wasp of many larvae of lepidopteran pests. The lipid content during developmental stages of M. pulchricornis was measured; it was higher in the larval and pupal stages but declined from six-day-old pupae. Lipid accumulation constantly decreased in the adult stage, even after feeding on honey solutions. To investigate the roles of FASs in lipid synthesis in M. pulchricornis, four FAS genes (MpulFAS1~4) were identified from the transcriptome database of M. pulchricornis. All FAS genes included full-length open reading frames and shared 72-79% similarity with the sequences of Microplitis demolitor. qRT-PCR validation showed that all four FASs had the highest expression after the adult wasps were fed on honey diets. MpulFAS1 and MpulFAS2 reached their expression peaks at the adult stage but MpulFAS3 and MpulFAS4 peaked at the larval stage. To further study the function of FASs, dsRNA injection knocked down the expression of four MpulFASs and resulted in a significant decline of lipid content at the adult stage in M. pulchricornis. Results from this study suggest that M. pulchricornis adults cannot accumulate lipid content effectively and FASs may still contribute to lipid synthesis in the adult stage. This broadens the knowledge on the ability of lipid synthesis in parasitoid wasps and provides insight into the roles of FASs in insects with parasitic life-history traits.

Loss of dominant caterpillar genera in a protected tropical forest.

Reports of biodiversity loss have increasingly focused on declines in abundance and diversity of insects, but it is still unclear if substantive insect diversity losses are occurring in intact low-latitude forests. We collected 22 years of plant-caterpillar-parasitoid data in a protected tropical forest and found reductions in the diversity and density of insects that appear to be partly driven by a changing climate and weather anomalies. Results also point to the potential influence of variables not directly measured in this study, including changes in land-use in nearby areas. We report a decline in parasitism that represents a reduction in an important ecosystem service: enemy control of primary consumers. The consequences of these changes are in many cases irreversible and are likely to be mirrored in nearby forests; overall declines in the region will have negative consequences for surrounding agriculture. The decline of important tropical taxa and associated ecosystem function illuminates the consequences of numerous threats to global insect diversity and provides additional impetus for research on tropical diversity.

Performance of Trichogramaspp in small tomato borer (Neoleucinodes elegantalisGuenée): Pest management with egg parasitoid

The tomato is a crop of great importance for Brazilian agriculture. Among the most damaging pests, the small tomato borer, Neoleucinodes elegantalis Guenée (Lepidoptera: Crambiadae) has caused great losses, since they directly reach the fruits to be commercialized, being used for its handling a large volume of insecticides. In this way, the use of alternative techniques that help in the management of this pest becomes of great importance. Among them, the use of the egg parasitoid Trichogrammaspp. has been promising. Thus, the present study aimed to evaluate the performance of Trichogrammaspecies and/or strains in N. elegantalisby selection of strains. The selection was made based on four lineages maintained in the Nucleus of Scientific and Technological Development in Phytosanitary Management of Pests (NUDEMAFI), being three strains of the species T. pretiosumand one of T. galloispecies. The parameters evaluated were percentage of parasitized eggs, egg viability, number of individuals per eggs, sex ratio and number of Trichogrammaspp. to be released. The T. galloi(T. g1) showed the best parameters for selection of the strain. Estimating the optimal number of T. g1 in eggs of small-fruit-borerwas 82 individuals per egg parasitoid. Therefore, this strain wasselected for the management of the small tomato-borer, whose eggs presented favorable physicochemical characteristics for the development of the parasitoid.

The sex ratio of the koinobiont parasitoid Microcharops anticarsiae Gupta remains female-biased on young larvae of velvetbean in the laboratory environment

The natural parasitic behavior of parasitoidsshould be known by those in charge of planning strategies for the biological control of pests; therefore, the aim of the present study was to determine the larval instar of Anticarsia gemmatalisHübner parasitized by Microcharops anticarsiaeGupta in the field and the implication of such parasitic behavior in the sex ratio in the laboratory environment. The length of each larval instar of A. gemmatalisparasitized by M. anticarsiaein the field was determined, and the egg-to-pupa period of the parasitoid and its larval instar lengths were plotted in Gantt charts. According to the chart, A. gemmatalis was parasitized at the first (15%) and second (85%) larval instars in the field, but the length of the first, second and third larval instars of this species was not affected by the parasitism by M. anticarsiaein the field; however, its fourth larval instar was extended and the fifth one was shortened in 2015 but not affected in 2016. The sex ratio of A. gemmatalislarvae parasitized byM. anticarsiaein the field was female-biased, and the sex ratio of early parasitized larvae (3-day old) in the laboratory environment was also female-biased for three cultivated generations. The ‘generation’ factor has affected the egg-to-pupa, pupal and egg-to-adult periods of M. anticarsiae, since females pupated earlier than males in the egg-to-pupa period. Based on the results, M. anticarsiaemostly parasitized the second larval instar of A. gemmatalisin the field, and parasitism in 3-day old larvae in the laboratory environment produced female-biased sex ratio in M. anticarsiae, regardless of the generation.