Search

In this study, we used the specialist egg parasitoid Trichogramma galloi Zucchi, 1988 (Hymenoptera: Trichogrammatidae) to test whether development over multiple generations on a factitious host would later influence performance on the target pest. We also investigated possible adaptations to laboratory rearing conditions by monitoring over 50 and 46 generations life history traits of T. galloi populations maintained on the natural [Diatraea saccharalis (Fabr., 1794) (Lepidoptera: Crambidae)] and factitious host [Ephestia kuehniella (Zeller, 1879) (Lepidoptera: Pyralidae)], respectively. We detected a possible sign of adaptation to rearing conditions in early generations on the emergence of the population maintained on the natural host. We also verified a reduction in fecundity and emergence of parasitoids maintained on the factitious host when fitness was evaluated on the natural host, confirming the prediction that the use of factitious hosts can lower fitness on the target pest. The importance of these results for the effectiveness of biological control programs is discussed.

The sugarcane borer, Diatraea saccharalis (F.), is a major maize borer pest and a target of transgenic maize expressing Bacillus thuringiensis (Bt) proteins in South America and the mid-southern region of the United States. Evolution of resistance in target pest populations is a great threat to the long-term efficacy of Bt crops. In this study, we compared the genetic basis of resistance to Cry1Ab protein in 3 resistant colonies of sugarcane borer established from field populations in Louisiana, USA. Responses of larvae to the Cry1Ab protein for the parental and 10 other cross colonies were assayed in a diet-incorporated bioassay. All 3 resistant colonies were highly resistant to the Cry1Ab protein with a resistance ratio of >555.6 fold. No maternal effect or sex linkage was evident for the resistance in the 3 colonies; and the resistance was functionally nonrecessive at the Cry1Ab concentrations of ≤ 3.16 μg/g, but it became recessive at ≥10 μg/g. In an interstrain complementation test for allelism, the F1 progeny from crosses between any 2 of the 3 resistant colonies exhibited the similar resistance levels as their parental colonies, indicating that the 3 colonies most likely shared a locus of Cry1Ab resistance. Results generated from this study should provide useful information in developing effective strategies for managing Bt resistance in the insect.

Use of genetically modified hybrids of maize, Zea mays L., is a pest management tool with special significance when a pest such as sugarcane borer, Diatraea saccharalis (F.) (Lepidoptera: Crambidae), becomes less responsive to conventional control methods. Resistance of genetically modified maize hybrids ‘AgrisureTM 3000 GT’ and ‘Agrisure® VipteraTM 3111’ were evaluated against stalk borers and compared with conventional hybrids with or without insecticide. During evaluation, few borers were found, especially during the first year (2012), but, in most cases, stalk damage by larvae was less in AgrisureTM 3000 GT and Agrisure® VipteraTM 3111 than in their conventional isolines. Insecticide did not prevent damage by the pest and even treated conventional maize was damaged. Use of AgrisureTM 3000 GT and Agrisure® VipteraTM 3111 hybrids can be a management tool to prevent damage by sugarcane borer in maize.

Paraíba is prominent in the sugarcane production, being the third state with highest productive impact in the Northeast. In the 2018/2019 harvest, the state processed 5,675,107.870 million tons destined to the production of 118 thousand tons of sugar and 382 thousand m³ of ethanol. Among the multiple aspects that permeate the sugarcane culture, this study focus on the biological control, more precisely the biological cycle and behavioral aspects of Cotesia flavipes and Diatraea saccharalis produced in laboratory, on the Paraíba north coast. The research experiments were carried out at the Mass Production of Biological Control Laboratory (LPMCB) of the Paraíba Sugarcane Growers Association (ASPLAN), in Mamanguape, the north coast of Paraíba. Regarding the C. flavipes insects there were measured the egg-larva duration; the pupa duration; the quantitative of adults; the number of cocoons per caterpillar; the pupae viability; the sex ratio at the three temperatures (21, 25 and 29oC) and the efficiency among male and female handlers. Regarding the D. saccharalis pest host behavioral variables, it was observed the D. saccharalis egg-adult biological cycle, the larvae and pupae viability, adult sex ratio and the number of larvae per couple. In the first stage, corresponding to the egg-adult life biological cycle evaluation, the experiment used 34 couples randomly selected from the laboratory commercial creation, individually accommodated. In the second stage, to diagnose the larva-pupa, larva-adult and pupa-adult viability, as well as the D. saccharalis adult sex ratio, 600 larvae were collected during five weeks, 120 units per week. In the third stage, regarding the experiment evaluations to measure the number of larvae per couple, it was necessary to perform four treatments with 10 repetitions each, using one adult couple of insects per mating chamber. As analysis of variance was performed and the average was compared through the statistical program of the Student Newlman Keuls Test – Cloud Radio Access Networks (CRAN) version 2019. In the results obtained by the study, the laboratory-produced parasitoids behavioral aspects present differences among the controlled temperatures. Concluding that the parasitoid sample presents satisfactory quality to the analyzed parameters and that temperature is an important factor to extend or reduce the C. flavipes and D. saccharali life cycle. Nenhuma A Paraíba é proeminente na produção de cana-de-açúcar, sendo o terceiro estado com maior impacto produtivo no Nordeste. Na safra 2018/2019, o estado processou 5.675.107,870 milhões de toneladas destinadas à produção de 118 mil toneladas de açúcar e de 382 mil m3 de etanol. Dentre os múltiplos aspectos que perpassam pela cultura da cana-de-açúcar, esse estudo privilegia o controle biológico, mais precisamente o ciclo biológico e os aspectos comportamentais de Cotesia flavipes e Diatraea saccharalis produzidas em laboratório, no litoral norte paraibano. Os experimentos da pesquisa foram desenvolvidos no Laboratório de Produção Massal de Controle Biológico (LPMCB) da Associação de Plantadores de Cana da Paraíba (ASPLAN), em Mamanguape, no litoral norte da Paraíba. Em relação aos insetos C. flavipes foram mensuradas a duração de ovo-larva; a duração de pupa; o quantitativo de adultos; a quantidade de casulos por lagarta; a viabilidade de pupas; a razão sexual nas três temperaturas (21, 25 e 29⁰C) e a eficiência entre manipuladores masculino e feminino. No tocante às variáveis comportamentais do hospedeiro da praga D. saccharalis, foram observados o ciclo biológico da D. saccharalis do ovo-adulto, a viabilidade de larvas e pupas, e razão sexual dos adultos e a quantidade de larvas por casais. Na primeira etapa, correspondente à avaliação do ciclo biológico de vida ovo-adulto, o experimento utilizou 34 casais selecionados aleatoriamente da criação comercial do laboratório, acomodados de modo individualizado. Na segunda etapa, para diagnosticar a viabilidade de larva-pupa, larva-adulto e pupa-adulto, bem como a razão sexual dos adultos de D. saccharalis, foram coletadas 600 larvas durante cinco semanas, sendo 120 unidades semanais. Na terceira etapa, em relação às avaliações do experimento para mensurar a quantidade de larvas por casais, fez-se necessário executar quatro tratamentos com 10 repetições cada um, sendo utilizado um casal adulto de inseto por câmara de acasalamento. Realizou-se uma análise de variância e a média comparada pelo programa estatístico do teste de Student-Newlman-Keuls conhecido por Cloud Radio Access Networks (CRAN), versão 2019. Nos resultados obtidos no presente estudo, os aspectos comportamentais de parasitoides produzidos em laboratório apresentam diferenças entre as temperaturas controladas. Concluindo que a amostra de parasitoide apresenta qualidade satisfatória para os parâmetros analisados e que a temperatura é um fator importante para prolongar ou diminuir o ciclo de vida de C. flavipes e D. saccharalis.

La mayor plaga de caña de azúcar en América la constituyen los barrenadores del tallo, Diatraea spp. (Lepidoptera: Crambidae) y en Colombia los estudios de resistencia varietal solo contemplan hasta el momento, evaluaciones en campo sujetas a la dinámica, distribución y nivel poblacional del barrenador y no permiten caracterizar la resistencia o susceptibilidad de las variedades cuando diferentes especies coexisten en un área. En este trabajo se desarrolló una metodología para establecer la resistencia y/o susceptibilidad de diferentes variedades de caña frente a Diatraea. Se seleccionaron genotipos de caña de azúcar con daño contrastante (testigos) a Diatraea spp. bajo condiciones de campo, luego se evaluó bajo condiciones de casa de malla el efecto de estas variedades contrastantes (CC 93-3826, susceptible y CC 93-3895, resistente) sobre el desarrollo de biología de D. saccharalis evaluando la densidad y edad de las larvas y el sitio de infestación en la planta. Posteriormente, estos dos genotipos se evaluaron con D. saccharalis, D. busckella, D. tabernella, D. indigenella, indicando que la resistencia no dependió de la especie del barrenador por lo cual finalmente, se validó la metodología de caracterización de resistencia a D. saccharalis empleando variedades comerciales. Para caracterizar la resistencia o susceptibilidad de las variedades se puede utilizar D. saccharalis empleando en la comparación las variedades testigo y las variables de daño en la planta (porcentaje de entrenudos barrenados, perforaciones de entrada, perforaciones de salida), recuperación de individuos según sus estados de desarrollo (larvas, pupas y adultos) y la Relación de Resistencia Relativa (RRR4) que contempla el daño generado por el insecto en cogollo, hojas y tallos, y la capacidad de la variedad para evitar su desarrollo de pupa y/o adulto. Maestría

The sugarcane borer Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) is considered the main sugarcane pest in many countries. The use of plant genotypes less preferred by insects are among the alternative methods to control this species which can be used alone or associated with other control methods such as biological control in Integrated Pest Management (IPM) programs. We assessed if the nonpreference for oviposition of D. saccharalis in sugarcane genotypes established by seedlings is different according to ripening group and plant age. For that purpose, four experiments were performed: 1) seedlings of early-ripening genotypes, 2) seedlings of late-ripening genotypes, 3) and mix of early- and late-ripening genotypes, seedlings, and 4) plants. There were least preferred genotypes for oviposition by D. saccharalis among seedlings of early-ripening (RB965902 and RB966928) and late-ripening (RB987935) genotypes. It was also observed when the groups were mixed as seedlings (RB965902) or plants (RB925345). The nonpreference for egg deposition in different ripening groups and plant age might be useful to integrate with other strategies for the management of D. saccharalis. Moreover, results of egg distribution might indicate the likely position of resistance factors on leaves, whether morphological or chemical.

El barrenador de caña de azúcar Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) es la plaga más importante del cultivo en Tucumán, Argentina. Los estadios larvales más avanzados perforan los tallos facilitando la colonización de microorganismos que reducen indirectamente el rendimiento y la calidad del azúcar. El objetivo del presente trabajo fue optimizar sistemas de fenotipado de D. saccharalis en caña de azúcar, en condiciones controladas, con el fin de evaluar diferentes estrategias de manejo de la plaga. En primer lugar, diferentes números de larvas neonatas fueron colocadas en el cogollo de plantines de caña de azúcar de dos meses de edad de las variedades TUC 95-10, TUC 03-12 y LCP 85-384. Por otro lado, en plantas individuales de seis meses de edad de TUC 95-10 se inocularon 10 larvas de diferentes estadios y se determinó el número de perforaciones y de vainas dañadas, la longitud total del túnel y elsíntoma del corazón muerto. En ensayos in vitro se inocularon dos larvas neonatas en ápices caulinares extraídos de plantines y se determinó el porcentaje de supervivencia de larvas. Todos los ensayos se realizaron en condiciones controladas (28-30ºC; 50-70% de HR), con dos o tres repeticiones y con 5 - 10 unidades experimentales por tratamiento. En plantines se observó el síntoma del corazón muerto en todos los tratamientos con diferente número de larvas neonatas. Las plantas de seis meses de edad presentaron daños en vaina y tallo cuando se infestaron con los estadios larvales L2, L3 y L4, mientras que las larvas neonatas solo produjeron daño en la vaina. En los ensayos de laboratorio el porcentaje de supervivencia de larvas obtenido fue elevado. Los resultados sugieren que diferentes sistemas de fenotipado empleando material vegetal de distinta edad fueron optimizados y están disponibles para evaluar potenciales estrategias de manejo del barrenador. Sugarcane borer Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae) is the most important sugarcane pest in Tucumán, Argentina. Older larvae bore into the stalks, facilitating microorganism colonization which indirectly reduces yield and quality of sugar. The aim of the present work was to optimize a sugarcane plant phenotyping method with D. saccharalis under controlled conditions to evaluate different strategies to manage the pest. Different numbers of neonate larvae were placed in the leaf whorl of sugarcane seedling (2-months-old) of cultivars TUC 95-10, TUC 03-12 and LCP 85-384. On the other hand, on single plants 6-month old of TUC 95-10, 10 larvae of several instars were added and the number of perforations and damaged sheath, the tunnel total length and the dead heart symptom were evaluated. In in vitro tests, immature leaf roll disks cut from seedlings were inoculated with two neonate larvae and the larval survival percentage was determined. Each assay was repeated twice or three times with 5 -10 replicates per treatment and conducted under controlled conditions (28-30ºC; 50-70% RH). In seedlings the symptom of the dead heart was observed in all the treatments with different larval number. In the case of the 6-month-old plants, damage in the sheath and stem were observed when infested with L2, L3 and L4 instars, whereas neonate larvae only produced sheath damage. In the laboratory tests, the survival percentage of larvae obtained was high. The results suggest that several methodologies were optimized to evaluate different types of plant material, which are available to study potential strategies for sugarcane borer management. Fil: Budeguer, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina Fil: Perera, María Francisca. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina Fil: Michavila, Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina Fil: Racedo, Josefina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina Fil: Vera, Alejandro. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina Fil: Noguera, Aldo Sergio. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina Fil: Cuenya, María Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán; Argentina. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina Fil: Castagnaro, Atilio Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina

A study was conducted in Florida to determine sugarcane borer, Diatraea saccharalis (F.), injury and infestation levels in sugarcane (Saccharum spp. hybrids), D. saccharalis parasitism rates, and ant foraging activity in 32 commercial fields as affected by soil type (shallow organic vs deep organic vs mineral). In 2017 and 2018, each field was sampled four times during the summer for D. saccharalis by inspecting 100 sugarcane stalks and for foraging ants using plastic tubes baited with hot dog at 12 locations. One non-parasitized D. saccharalis larva was collected in 2017 and in 2018 out of 12,100 and 12,600 stalks sampled, respectively. Additional sampling of 50 stalks per field in October showed that 0.6% (2017) and 0.1% (2018) of the sugarcane stalks had bored internodes, and one Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) cocoon mass was observed. Seven ant species foraged in sugarcane fields, including the red imported fire ant, Solenopsis invicta Buren, which was the most abundant ant. Solenopsis invicta was not affected by soil type; however, sugarcane fields on shallow organic soils might represent a more suitable environment. The third most abundant foraging ant, Nylanderia bourbonica (Forel), was more abundant in mineral soil fields than in shallow and deep organic soil fields. Results suggest that D. saccharalis population levels in Florida sugarcane are extremely low under current production conditions regardless of soil type. In addition, the observation of C. flavipes, S. invicta, and six other ant species suggest that biological control contributes to these low D. saccharalis population levels.

The endoparasitoid wasp Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) is inundatively released in Brazilian sugarcane plantations to control the sugarcane borers Diatraea saccharalis (Fabricius) and Diatraea flavipennella (Box) (Lepidoptera: Crambidae). In conjunction with these releases, several synthetic insecticides are used to control the neonate larvae of these pests. We assessed the lethal and transgenerational sublethal effects of seven of these insecticides on C. flavipes. Leaf discs were sprayed at the highest field concentrations of chlorantraniliprole, lambda-cyhalothrin + chlorantraniliprole, chlorfluazuron, triflumuron, lambda-cyhalothrin + thiamethoxam, tebufenozide, and novaluron. Distilled water was used as a negative control. Newly emerged females (24 h old) were placed in Petri dishes containing the treated leaves, and the lethal and transgenerational sublethal effects were assessed for the next two generations. Lambda-cyhalothrin + chlorantraniliprole and lambda-cyhalothrin + thiamethoxam caused 100% mortality of the parasitoid and were highly persistent, causing more than 30% mortality at 30 days after spraying. Chlorantraniliprole, chlorfluazuron, novaluron, and triflumuron did not cause significant mortality compared to the negative control, but did have transgenerational sublethal effects. The length of the tibia of the right posterior leg, used as a growth measurement, was reduced in the progeny (F1 generation) of exposed female parasitoids. In addition, chlorantraniliprole increased and chlorfluazuron reduced the proportion of females in the F1 generation, whereas novaluron reduced the proportion of females in the F2 generation. Overall, only tebufenozide was considered harmless to C. flavipes. The results of this study suggest that lambda-cyhalothrin + chlorantraniliprole and lambda-cyhalothrin + thiamethoxam are harmful to C. flavipes, although field studies are needed to obtain results for actual sugarcane crops.

Made available in DSpace on 2019-10-06T16:47:23Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-11-30 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) The relevance of Bacillus thuringiensis in pest control strategies have been increasing in recent decades. This entomopathogenic microorganism is considered safe, and its action is highly selective to target organisms. Its toxic effect is attributed to the toxins synthesized during sporulation. The nature of the produced toxins depends on the bacterial variety. Some varieties of B. thuringiensis can synthesize from one to eight distinct toxins, which have specific effects on different orders of susceptible insects. The sugarcane borer, Diatraea saccharalis, is a holometabolous lepidopteran that causes severe damage to sugar cane cultures during its larval phase. Therefore, to evaluate B. thuringiensis serovar Aizawai GC-91 efficiency and its effects on the midgut of first instar D. saccharalis larvae, we reared the insects with contaminated artificial diet for 144 h. Larvae mortality during this period revealed that 5, 10, and 20 g/L concentrations were the most efficient, resulting in 100% mortality of treated larvae, with LC50 and LC90 estimated at 0.307 and 1.330 g/L, respectively. Furthermore, histological and ultrastructural analyses revealed damage to midgut cells. Within the first 24 h of treatment, the midgut of infected insects presented peritrophic membrane degeneration, cytoplasmic vacuolization, and cellular hypertrophy; spherites and calcium granules were also observed. At 48 h of treatment, the digestive system had collapsed, with microvilli degeneration, basement membrane and muscular fiber bundles disruption, and cellular lysis. These results confirm the toxicity of the B. thuringiensis serovar Aizawai GC-91 on D. saccharalis larvae and its potential use as a biocontroller against this pest species. Laboratory of Biological Control Morphology and Insect Cytogenetics Department of Biotechnology Genetics and Cell Biology State University of Maringá - UEM Laboratory of Insects Department of Morphology Institute of Biosciences of Botucatu São Paulo State University - UNESP Microscopy Center Complex of Research Support Centers of the State University of Maringá - UEM Laboratory of Animal Genetics Department of Biotechnology Genetics and Cell Biology State University of Maringá - UEM Laboratory of Microbiology Department of Biotechnology Genetics and Cell Biology State University of Maringá - UEM Laboratory of Insects Department of Morphology Institute of Biosciences of Botucatu São Paulo State University - UNESP

Diatraea saccharalis F is considered the most important pest of sugarcane in the United States. This article focuses on the history of pest management as it relates to the control of this stem borer in Louisiana sugarcane, and how control practices have become more in tune with integrated pest management paradigms. Various pest management strategies are employed against D. saccharalis and the interactions between each of these provide farmers with the tools needed to curb damaging infestations. However, the invasion of the Mexican rice borer, Eoreuma loftini (Dyar), and other confounding environmental factors have presented farmers, consultants, and researchers with new pest management challenges. We address these challenges and provide an overview of ongoing developments, particularly in the Louisiana sugarcane pest management program.

Koinobiont endoparasitoid wasps regulate the host’s physiology to their own benefit during their growth and development, using maternal, immature and/or derived-tissue weaponry. The tools used to subdue the wasps’ hosts interfere directly with host transcription activity. The broad range of host tissues and pathways affected impedes our overall understanding of the host-regulation process during parasitoid development. Next-generation sequencing and de novo transcriptomes are helpful approaches to broad questions, including in non-model organisms. In the present study, we used Illumina sequencing to assemble a de novo reference transcriptome of the sugarcane borer Diatraea saccharalis, to investigate the regulation of host gene expression by the larval endoparasitoid Cotesia flavipes. We obtained 174,809,358 reads and assembled 144,116 transcripts, of which 44,325 were putatively identified as lepidopteran genes and represented a substantial number of pathways that are well described in other lepidopteran species. Comparative transcriptome analyses of unparasitized versus parasitized larvae identified 1,432 transcripts of D. saccharalis that were up-regulated under parasitization by C. flavipes, while 1,027 transcripts were down-regulated. Comparison of the transcriptomes of unparasitized and pseudoparasitized D. saccharalis larvae led to the identification of 1,253 up-regulated transcripts and 972 down-regulated transcripts in the pseudoparasitized larvae. Analysis of the differentially expressed transcripts showed that C. flavipes regulated several pathways, including the Ca+2 transduction signaling pathway, glycolysis/gluconeogenesis, chitin metabolism, and hormone biosynthesis and degradation, as well as the immune system, allowing us to identify key target genes involved in the metabolism and development of D. saccharalis.

Made available in DSpace on 2019-10-06T17:12:03Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-09-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Biological control using entomopathogens and natural enemies is an ecofriendly method for pest management in agriculture. Biological control agents often can be simultaneously employed and compatibility between agents may improve pest suppression. We investigated the influence of the entomopathogen Bacillus thuringiensis (Bt) on the immune system of the sugarcane borer Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) to determine if such changes impact parasitization by Cotesia flavipes Cameron, 1891 (Hymenoptera: Braconidae). The immune response of surviving D. saccharalis larvae fed with an LC25 dosage of a Bt-based biopesticide (Dipel®) was analyzed (total hemocyte count, hemocyte adhesion, and activities of phenoloxidase and lysozyme). Furthermore, the suitability of surviving Bt-fed larvae as hosts for C. flavipes was assessed by measuring parasitoid attributes such as number and size of teratocytes, weight of pupae, length of adult female tibia and number of emerged adults. Total hemocyte count, but not hemocyte adhesion, total protein content and phenoloxidase activity increased in the hemolymph of non-parasitized Bt-fed larvae (Bt-NP) compared to control larvae (NBt-NP). Lysozyme activity increased only after parasitization without Bt exposure (NBt-P). After parasitization, the immunological parameters activated in Bt-NP larvae decreased to levels at or below those observed in control larvae, showing that C. flavipes can regulate the activated immune response of Bt-fed larvae. The development of C. flavipes was not impaired in Bt-fed larval hosts (Bt-P); no changes were observed for teratocyte size, weight of pupal mass, length of hind tibia and number of adults emerged. São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences São Paulo State University (Unesp) School of Agricultural and Veterinarian Sciences

A Cry1Ac-expressing sugarcane cultivar, CTC91087-6, has been developed by Centro de Tecnologia Canavieira (CTC) to be resistant to the sugarcane borer (Diatraea saccharalis). This genetically modified event was developed using Agrobacterium-mediated transformation and the help of the selectable marker phosphinothricin N-acetyltransferase (PAT) expressed from bar gene. We describe here a detailed characterization of CTC91087-6 event with respect to protein expression, nutritional composition, and assessment of its derived DNA and proteins in raw sugar. Expression of the Cry1Ac and PAT (bar) proteins produced by CTC91087-6 was evaluated in different tissues and at different times during the growing season. The new proteins are preferentially expressed in leaves, are produced at low levels in stalks, and are near the limits of detection in root tissues. The levels of Cry1Ac were much higher than PAT in all evaluated tissues. Furthermore, Cry1Ac levels in CTC91087-6 leaves are stable at various times during sugarcane cultivation cycle, assuring borer control throughout the complete crop cycle. Assessment of CTC91087-6 tissues for key food and feed nutrients as recommended by OECD to assess the safety of new varieties of sugarcane showed compositional equivalence to the conventional counterpart CTC9001 and to other commercial sugarcane varieties used as references. Raw sugar samples produced from CTC91087-6 did not contain DNA corresponding to cry1Ac and bar genes nor DNA specifically derived from CTC91087-6. In a similar way, there is no detection of Cry1Ac and PAT proteins in raw sugar produced from CTC91087-6. Taken together these results show that CTC91087-6 stably expresses Cry1Ac and PAT proteins and is substantially equivalent to the conventional counterpart CTC9001.

This study evaluated the effects of the sugarcane borer Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae) on cultivars of sweet and biomass sorghum for the selection of resistant cultivars. The present work consisted of two trials, with natural pest infestation. In the first one, 10 sweet sorghum cultivars were analyzed for the following variables: plant height, number of healthy and damaged internodes, gallery position and size, stem infestation level and soluble solids content (°Brix). In the second trial, it was analyzed 16 genotypes of high biomass sorghum, with the same variables above mentioned, in addition to the lignin, cellulose and hemicellulose contents. Among sweet sorghum genotypes evaluated, the genotype CMSXS647 stood out due to the traits: plant height, infestation level, gallery size and soluble solids content. Among the sorghum genotypes evaluated, CMSXS7030, CMSXS7012 and CMSXS7028 presented ideal characteristics for infestation level, plant height and number of lignocellulosic compounds. Such information, in addition to supporting the bioenergy sorghum breeding program, will assist in integrated pest management for sorghum cultivation. Foram estudados os efeitos causados pela broca-do-colmo Diatraea saccharalis (Fabricius, 1794) (Lepidoptera: Crambidae), em cultivares de sorgo sacarino e biomassa visando seleção de cultivares resistentes à praga. O presente trabalho foi constituído de dois ensaios, com infestação natural da praga. No primeiro, 10 cultivares de sorgo sacarino foram analisadas quanto às seguintes variáveis: altura das plantas, quantidade de internódios sadios e com injúrias, posição e tamanho da galeria, intensidade de infestação de colmos e teor de sólidos solúveis (°Brix). No segundo ensaio, foram analisados 16 genótipos de sorgo biomassa, com as mesmas variáveis supracitadas, além dos teores de lignina, celulose e hemicelulose. Entre os genótipos de sorgo sacarino avaliados, o genótipo CMSXS647 foi o que se destacou em função das características: altura de plantas, intensidade de infestação, tamanho de galerias e teor de sólidos solúveis. Entre os genótipos de sorgo biomassa avaliados: CMSXS7030, CMSXS7012 e CMSXS7028 apresentaram características ideais para intensidade de infestação, altura de plantas e quantidade de compostos lignocelulósico. Tais informações, além de prover o programa de melhoramento de sorgo energia podem ajudar o programa de MIP para a cultura do sorgo, uma vez que o produtor conhece a suscetibilidade dos materiais escolhidos.

The sugarcane borer, Diatraea saccharalis (F.), rice stalk borer, Chilo plejadellus Zincken, and Mexican rice borer, Eoreuma loftini (Dyar), are stem borers (Lepidoptera: Crambidae) that infest rice (Oryza sativa L.) in the southern United States. A 2-yr study was conducted to determine stem borer injury, infestation, and parasitism levels in Florida. Thirty commercial rice fields were selected during the 2017 and 2018 growing seasons throughout the rice production region in southern Florida. Sampling for stem borer injury and infestations was conducted in each field between the milk and early maturation stages by observing plants at 10 locations, with three 1-m2 quadrats per location. In addition, monitoring for E. loftini adults was conducted using one pheromone trap adjacent to each field. In 2017, the number of rice tillers exhibiting stem borer injury averaged 0.024 tillers/m2 and infestation levels averaged 0.008 stem borers/m2, with only D. saccharalis being observed. In 2018, injury and infestation levels averaged 0.062 injured tillers/m2 and 0.023 D. saccharalis larvae or pupae/m2, respectively. The solitary parasitoid Alabagrus stigma Brullé (Hymenoptera: Braconidae) parasitized 33 and 40% of the collected D. saccharalis in 2017 and 2018, respectively. In addition, pheromone traps did not capture E. loftini adults. This study shows that D. saccharalis infests rice in Florida but at relatively low levels not threatening production and that rice fields are habitats for D. saccharalis parasitoids. This study also suggests that C. plejadellus and E. loftini do not occur in southern Florida.

The development of processes for the production of cellulases with high specific activity is a challenge for industrial biotechnology. Although the performance of commercial cellulases has improved significantly in the last decade, the same has not happened with cellulases produced in research laboratories, being the production of this type of enzyme still a high cost factor in the processes that require its use. Thus, the present study aimed to investigate the presence of cellulolytic bacteria isolated from the intestinal tract of Diatraea saccharalis larvae in order to determine their potential use in the hydrolysis of sugarcane bagasse. For this, cellulolytic bacteria were screened from the intestinal tract of Diatraea saccharalis larvae through specific culture media using sugarcane bagasse and carboxymethylcellulose (CMC) as sole carbon sources. In this scenario, sugarcane bagasse was used as the inducible biomass of cellulase by means of liquid fermentation. Through an experimental planning were determined the best conditions of cellulase production (inoculum concentration and pH). The physico-chemical-morphological characterization of the biomass was performed by means of chromatographic (HPLC) and spectroscopic analyzes (FTIR, XRD). Then electrophoretic techniques were used to measure the endoglucanase protein profile of cellulolytic bacterial isolates, electrophoretic purification techniques to determine molecular weight of proteins and molecular techniques (PCR and DNA sequencing) for bacterial genome identification. The results of chemical characterization showed that cellulose and hemicellulose decreased after pretreatment, suggesting carbohydrate loss and formation of other products such as furfural, HMF, acetic acid and formic acid. FTIR spectra revealed similarity between untreated and pretreated material spectra, qualitatively evidencing that pretreatment was efficient in extracting hemicellulose and lignin. Peaks in the XRD diffractograms confirmed the removal of lignin and hemicellulose from the pretreated biomass. However, for the crystallinity index there was no significant change (73.25 and 73.70% for untreated and pretreated biomass, respectively). Gram staining of cellulolytic bacterial isolates revealed the presence of one Gram-positive encapsulated bacillus and three Gram-negative bacteria. The degradation activity of CMC revealed higher extracellular cellulase activity for the isolates INTB2, INTB3 and INTB4. For extracellular endoglucanase activity, the 4 isolates reported similar patterns of endoglucanase excretion, however, the INTB4 isolate reported the lowest extracellular activity (3.0 cm). The results of cellulase production through the INTB3 isolate showed to be more stable compared to the other isolates INTB1, INTB2, INTB4. As for purification, the specific activity for the INTB3 extract was 30.13 U/mg for INTB4 19, 97, INTB2 11,15 and INTB1 5,53 U/mg, after precipitation with ammonium sulfate. Native PAGE presented to the four isolates 3 protein bands corresponding to ~ 89, 58 and 48 kDa. In SDS-PAGE the enzyme extracts investigated (crude and precipitated) reflect multiple proteins detected in the gel and show that the enzymes presented several bands (between 150 and 17 kDa). The zymogram-CMC analysis exhibited cellulolytic activity, suggesting that the enzymes were able to hydrolyze sodium carboxymethylcellulose and have at least two sizes, ~ 89 and 58 kDa. The method applied for the cellulase isolation of the INTB3 isolate presented a single peak of cellulolytic activity and through 12% SDS-PAGE, 3 protein bands were observed around 113, 76, 52 kDa. In the present study, of the microorganisms isolated for enzymatic production, INTB3 was identified as the main producer of cellulase, having the highest specific activity after partial purification (30.13 U/mg). A purificação da endoglucanase de INTB3 através da cromatografia 11 por exclusão de tamanho triplicou (96,25 UI/mL) a atividade específica celulolítica. Mais distante outros estudos tornam-se importantes para dar continuidade a estes experimentos para obter alto rendimento de produção, purificação e aplicação de celulase. CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior O desenvolvimento de processos para produção de celulases com alta atividade específica é um desafio para a biotecnologia industrial. Embora o desempenho das celulases comerciais tenha melhorado significativamente na última década, o mesmo não aconteceu com as celulases produzidas em laboratórios de pesquisa, sendo, a produção desse tipo de enzima ainda um fator de custo elevado nos processos que exigem seu uso. Dessa forma, o presente estudo teve como objetivo investigar a presença de bactérias celulolíticas isoladas do trato intestinal de larvas de Diatraea saccharalis a fim de determinar seu potencial uso na hidrólise do bagaço da cana-de-açúcar. Para isto, realizou-se uma triagem de bactérias celulolíticas do trato intestinal de larvas de Diatraea saccharalis através de meios de cultura específicos utilizando o bagaço da cana-de-açúcar e carboximetilcelulose – CMC como únicas fontes de carbono. Nesse cenário, utilizou-se como biomassa indutível de celulase o bagaço da cana-de-açúcar por meio de fermentação em estado líquido. Através de um planejamento experimental foram ,determinado as melhores condições de produção de celulase (concentração do inóculo e pH). Realizou-se a caracterização físico-química-morfológica da biomassa por meio de análises cromatográficas (CLAE) e espectroscópicas (FTIR, DRX). Em seguida, aplicou-se técnicas eletroforéticas para mensurar o perfil proteico da endoglucanase dos isolados bacterianos celulolíticos, técnicas de purificação associadas às eletroforéticas para determinar o peso molecular das proteínas e técnicas moleculares (PCR e sequenciamento de DNA) para identificação de genoma bacteriano. Os resultados de caracterização química mostraram que a celulose e hemicelulose diminuíram após o pré-tratamento, sugerindo perda de carboidratos e formação de outros produtos como furfural, HMF, ácido acético e ácido fórmico. Os espectros de FTIR revelaram semelhança entre os espectros dos materiais não tratados e pré-tratado, evidenciando, qualitativamente, que o pré-tratamento foi eficiente na extração da hemicelulose e lignina. Os picos nos difratogramas do DRX confirmaram a remoção de lignina e hemicelulose da biomassa pré-tratada. No entanto, para o índice de cristalinidade não houve mudança significativa (73,25 e 73,70% para biomassa não tratada e pré-tratada, respectivamente). A coloração de Gram dos isolados bacterianos celulolíticos revelou a presença de um bacilo Gram-positivo encapsulado, e três bactérias Gram-negativas. A atividade de degradação de CMC revelou maior atividade de celulase extracelular para os isolados INTB2, INTB3 e INTB4. Para atividade de endoglucanase extracelular, Os 4 isolados reportaram padrões semelhantes de excreção de endoglucanase, no entanto, o isolado INTB4 foi o que reportou menor atividade extracelular (3,0 cm). Os resultados de produção de celulase através do isolado INTB3 mostraram-se mais estáveis em comparação aos demais isolados INTB1, INTB2, INTB4. Quanto a purificação, após precipitação com sulfato de amônio a atividade específica para o extrato INTB3 foi de 30,13 U/mg, para INTB4 19,97, INTB2 11,15 e INTB1 5,53 U/mg. A PAGE nativa apresentou para os quatros isolados 3 bandas de proteínas correspondentes a ∼89, 58 e 48 kDa. No SDS-PAGE os extratos enzimáticos investigados (bruto e precipitado) refletem múltiplas proteínas detectadas no gel e revelam que as enzimas apresentaram várias bandas (entre 150 a 17 kDa). A análise do zimograma-CMC exibiu atividade celulolítica, sugerindo que as enzimas conseguiram hidrolisar a carboximetilcelulose sódica e possuem pelo menos dois tamanhos, ∼ 89 e 58 kDa. O método aplicado para o isolamento da celulase do isolado INTB3 apresentou um único pico de atividade celulolítica e através de SDS-9 PAGE a 12%, observou-se 3 bandas proteicas em torno de 113, 76, 52 kDa. No presente estudo, Dos microrganismos isolados para produção enzimática, o INTB3 foi identificado como o principal produtor de celulase, tendo a maior atividade específica após purificação parcial (30,13 U/mg). A purificação da endoglucanase de INTB3 através da cromatografia por exclusão de tamanho triplicou (96,25 UI/mL) a atividade específica celulolítica. Mais distante outros estudos tornam-se importantes para dar continuidade a estes experimentos para obter alto rendimento de produção, purificação e aplicação de celulase.

The sugarcane borer, Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae), is one of the main lepidopteran pests of sugarcane and maize. The association of insects with different environments and/or host plants may occur by adaptation and this can generate host races. Adaptation may produce phenotypic or genotypic variation, which results in the differences in bioecological characteristics such as reproductive compatibility that reduces gene flow among populations. The objective of this study was to determine the reproductive compatibility of three population combinations collected in various geographic locations and from different host plants, thereby determining the influence of geographic distance and/or insect plant association. Interpopulation crosses of D. saccharalis populations from Tucumán (maize and sugarcane) and Jujuy (sugarcane) provided evidence of pre-zygotic and post-zygotic incompatibility. The results indicate that gene flow barriers are influenced by the host plant. However, populations from various locations revealed that geographical location is the main factor influencing gene flow among populations of D. saccharalis. Fil: Fogliata, Sofia Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina Fil: Herrero, María Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina Fil: Vera, Martin Alejandro. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina Fil: Castagnaro, Atilio Pedro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina Fil: Gastaminza, Gerardo Alfredo. Gobierno de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial Obispo Colombres; Argentina Fil: Murúa, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Tecnología Agroindustrial del Noroeste Argentino. Provincia de Tucumán. Ministerio de Desarrollo Productivo. Estación Experimental Agroindustrial "Obispo Colombres" (p). Instituto de Tecnología Agroindustrial del Noroeste Argentino; Argentina

A T1 (sugarcane population originating from true seeds) and T2 (first sugarcane clonal stage) population were used to estimate genetic parameters and compare selection strategies for Diatraea saccharalis (Lepidoptera: Crambidae) resistance in sugarcane. In the T1 stage, heritability at the family mean level (h²=0.77) was higher than individual genotype heritability (h²=0.16), and the additive genetic effect was more important for sugarcane borer resistance than non-additive effects. In addition, there was high genotypic variance among and within full-sib families. In the T2 population, genotypic variance was high, and heritability at the clone mean level was moderate (h²=0.61). We can conclude that family experiments enable selection of more promising families and parents for borer resistance. However, due to high genotypic variance within families, family selection at the T1 stage must be followed by clone selection at the T2 stage. Made available in DSpace on 2019-11-08T18:18:39Z (GMT). No. of bitstreams: 1 2019M.DeonCBABGenetic.pdf: 409995 bytes, checksum: 180f20613e1186d677c2f71ea30e6383 (MD5) Previous issue date: 2019

Fungal phytopathogens are known to induce changes in plant metabolite profile and defense levels that consequently affect insect herbivores. Although it is expected that fungal plant infection may also affect herbivore natural enemies that are guided by plant chemical cues, few studies have addressed this interaction. Here, we examined the effect of infection in sugarcane by the red-rot fungus, which is usually associated with the injury of the sugarcane-borer Diatraea saccharalis, on plant defenses by assessing borer weight gain and the attractiveness of herbivore-induced plant volatiles to the parasitoid Cotesia flavipes. Olfactometer assays and GC–MS analysis showed that although red-rot-infected plants released a different volatile blend from mock-inoculated, the wasps showed no preference for either of the two treatments. Red-rot disease also caused qualitative and quantitative changes in the volatile blend emitted by herbivore-damaged plants relative to healthy and damaged plants, such as the addition of the fungal-derived 1-octen-3-ol and either a reduction or an increase of volatiles. These differences were detected by C. flavipes, which preferred volatiles released by herbivore-damaged healthy over herbivore-damaged infected plants. When given a choice between mock-inoculated and herbivore-damaged infected plants, the wasps preferred infected ones. Sugarcane-borer larvae were larger when fed on healthy plants relative to red-rot infected sugarcane plants, indicating that parasitoid wasps likely benefit from being attracted to volatiles of healthy over infected damaged sugarcane. Although the infection did not seem to disrupt the parasitoid host-location, red-rot disease attenuates the attractiveness of herbivore-induced sugarcane volatiles to C. flavipes.

SUGARWIN1 and 2 are defense proteins from sugarcane. Their gene expression is known to be induced in response to wound and Diatraea saccharalis damage. Although the recombinant SUGARWIN protein does not affect insect development, it promotes significant morphological and physiological changes in Fusarium verticillioides and Colletotrichum falcatum, which lead to fungal cell death via apoptosis. In this study, we deepen our understanding of the role of SUGARWINs in plant defense and the molecular mechanisms by which these proteins affect fungi by elucidating their molecular targets. Our results show that SUGARWINs play an important role in plant defense against opportunistic pathogens. We demonstrated that SUGARWINs are induced by C. falcatum, and the induction of SUGARWINs can vary among sugarcane varieties. The sugarcane variety exhibiting the highest level of SUGARWIN induction exhibited a considerable reduction in C. falcatum infection. Furthermore, SUGARWIN1 exhibited ribonuclease, chitosanase, and chitinase activity, whereas SUGARWIN2 exhibited only chitosanase activity. This variable enzymatic specificity seems to be the result of divergent amino acid composition within the substrate-binding site.

The objective of the present investigation was the characterization and molecular variation in Diatraea saccharalis Fabricius from the cultivation of Saccharum officinarum L. "Caña de azúcar" from La Libertad and Lima regions using RAPDS for its easy application and low cost. For this, the OPA-08, OPA-11, OPC-11, OPP-17 and GyakuU-13 markers were used. First, total DNA extraction was done with the help of commercial Kit, which was then PCR-tested with the following conditions: denaturation of the initial DNA was 94ºC for 3 minutes. This step was followed by 30 cycles of amplification (94 ° C: 1 min, 35 ° C: 1 min, 72 ° C: 1:30 min.). After the cycles, a final extension of 3 minutes was made at 72 ºC. PCR results were observed in 4% polyacrylamide gels. It was observed that OPA8 generated 18 bands, OPA11 23 bands, OPP17 12 bands, the OPC11 marker 19 bands and Gyaku13 23 bands. With this, matrices of presence and absence were filled and then entered into the Popgene32 program to perform the different statistical analyzes, showing that the populations have low intrepoblational and high intrapopulation genetic differentiation. Similarly, in the dendograms a grouping between the populations is observed of Casa Grande and Barranca, likewise, different groups and individuals are observed within each population. RESUMEN La presente investigación tuvo como objetivo la caracterización y variación molecular de las tres poblaciones de Diatraea saccharalis Fabricius proveniente del cultivo de Saccharum officinarum L. “caña de azúcar” de las regiones La Libertad y Lima haciendo uso de RAPDS. Para esto se utilizaron los marcadores OPA-08, OPA-11, OPC-11, OPP-17 y GyakuU-13. Primero se hizo extracción de ADN total con ayuda de Kit comercial a los cuales luego se realizó PCR con las siguientes condiciones: desnaturalización del ADN inicial fue de 94ºC por 3 minutos. Este paso fue seguido por 30 ciclos de amplificación (94ºC: 1 min, 35ºC: 1 min, 72ºC: 1:30 min.). Después de los ciclos, se realizó una extensión final de 3 minutos a 72 ºC. Los resultados de PCR fueron observados en geles de poliacrilamida al 4%. Se observó que OPA8 generó 18 bandas, OPA11 23 bandas, OPP17 12 bandas, el marcador OPC11 19 bandas y Gyaku13 23 bandas. Con esto se llenaron matrices de presencia y ausencia que luego fueron ingresadas en el programa Popgene32 para realizar los diferentes análisis estadísticos, obteniéndose que las poblaciones no se diferencian genéticamente entre ellas pero si dentro de ellas, del mismo modo se observó en los dendogramas un agrupamiento entre las poblaciones de Casa Grande y Barranca. Se llega a la conclusión que dentro de cada población existen sub grupos e individuos diferenciados genéticamente. Tesis

Background Sugarcane (Saccharum spp. hybrids) is considered the most globally important sugar-producing crop and raw material for biofuel. Insect attack is a major issue in sugarcane cultivation, resulting in yield losses and sucrose content reductions. Stem borer (Diatraea saccharalis F.) causes serious yield losses in sugarcane worldwide. However, insect-resistant germplasms for sugarcane are not available in any collections all over the world, and the molecular mechanism of insect resistance has not been elucidated. In this study, cry1Ac transgenic sugarcane lines were obtained and the biological characteristics and transgene dosage effect were investigated and a global exploration of gene expression by transcriptome analysis was performed. Results The transgene copies of foreign cry1Ac were variable and random. The correlation between the cry1Ac protein and cry1Ac gene copies differed between the transgenic lines from FN15 and ROC22. The medium copy lines from FN15 showed a significant linear relationship, while ROC22 showed no definite dosage effect. The transgenic lines with medium copies of cry1Ac showed an elite phenotype. Transcriptome analysis by RNA sequencing indicated that up/down regulated differentially expressed genes were abundant among the cry1Ac sugarcane lines and the receptor variety. Foreign cry1Ac gene and endogenous borer stress-related genes may have a synergistic effect. Three lines, namely, A1, A5, and A6, were selected for their excellent stem borer resistance and phenotypic traits and are expected to be used directly as cultivars or crossing parents for sugarcane borer resistance breeding. Conclusions Cry1Ac gene integration dramatically improved sugarcane insect resistance. The elite transgenic offspring contained medium transgene copies. Foreign cry1Ac gene integration and endogenous borer stress-related genes may have a synergistic effect on sugarcane insect resistance improvement. Electronic supplementary material The online version of this article (10.1186/s12870-018-1536-6) contains supplementary material, which is available to authorized users.

A expansão no cultivo da cana-de-açúcar atrai vários insetos-praga, representando um fator limitante à cultura canavieira no Brasil. O objetivo da pesquisa foi analisar aspectos, em laboratório, da broca da cana-de-açúcar Diatraea saccharalis como hospedeiro de Cotesia flavipes. O experimento foi desenvolvido em três etapas, de modo inteiramente casualizado. Na primeira etapa, correspondente à avaliação do ciclo biológico de vida ovo-adulto, o experimento utilizou 30 casais selecionados aleatoriamente da criação comercial do laboratório, sendo acomodados de modo individualizado. Na segunda etapa, realizou-se o diagnóstico da viabilidade de larva-pupa, larva-adulto e pupa-adulto, bem como a razão sexual dos adultos de D. saccharalis. Foram coletadas 600 larvas durante cinco semanas (120 unidades por semana). . Em todas as fases estudadas, os resultados destacam que a viabilidade desse hospedeiro apresenta índices acima de 90%. Na razão sexual dos adultos, as fêmeas são maioria. Durante o período de oviposição, a quantidade média obtidas de larva por casal foi de 243 indivíduos. Conclui-se que a temperatura é um fator importante para prolongar ou diminuir o ciclo de vida da D. saccharalis. Essa fase consta no material e métodos: A terceira etapa, em relação às avaliações do experimento para mensurar a quantidade de larvas por casais de D. saccharalis, executou-se quatro tratamentos com 10 repetições cada um, sendo utilizado um casal adulto de inseto por câmara de acasalamento, totalizando 400 casais de D. saccharalis. Observar sexto parágrafo da seção Material e Métodos (A terceira etapa, em relação às avaliações do experimento para mensurar a quantidade de larvas por casais de D. saccharalis, executou-se quatro tratamentos com 10 repetições cada um, sendo utilizado um casal adulto de inseto por câmara de acasalamento, totalizando 400 casais de D. saccharalis.)

Diatraea lineolata and Diatraea saccharalis (Lepidoptera: Crambidae) are moths with stemboring larvae that feed and develop on economically important grasses. This study investigated whether these moths have diverged from a native host plant, corn, onto introduced crop plants including sorghum, sugarcane, and rice. Diatraea larvae were collected from these four host plants throughout the year in El Salvador and were reared on artificial diet until moths or parasitoids emerged. Adult moths were subsequently identified to species. Amplified fragment length polymorphisms (AFLPs) and mitochondrial DNA cytochrome oxidase I (COI) were used to examine whether or not there was genetic divergence of D. lineolata or D. saccharalis populations on the four host plants. Percent parasitism was also determined for each moth on its host plants. D. lineolata was collected from corn in the rainy season and sorghum in the dry season. D. saccharalis was most abundant on sugarcane in the rainy season and sorghum in the dry season. The AFLP analysis found two genetically divergent populations of both D. lineolata and D. saccharalis. Both moths had high levels of parasitism on their dominant host plant in the rainy season, yet had low levels of parasitism on sorghum in the dry season. The presence of two genotypes of both Diatraea spp. on sorghum suggest that host‐associated differentiation is occurring on this novel introduced crop plant.

A seed mix strategy has been used to provide refuge to susceptible insects for resistance management in planting transgenic maize expressing Bacillus thuringiensis Berliner (Bt) proteins. To determine whether larval movement in a seed mix planting creates favorable conditions for resistant heterozygotes of a target pest, performance of Cry1Ab-susceptible (SS) and -heterozygous resistant (RS) populations of the sugarcane borer, Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae), was evaluated in sequential feeding on non-Bt and Cry1Ab (event MON 810) maize plant tissue. For each insect population, nine feeding sequences were employed. SS and RS feeding on non-Bt plants for their entire larval stages survived well and >60% of the adult pairs produced viable eggs, with an average of 269 progeny per female, whereas none of the two populations on Bt maize plants survived to the pupal stage. SS larvae could not develop to adults if the larvae fed on non-Bt plants for ≤15 days and then moved to Bt plants. In contrast, 4.2–29.2% of RS larvae that fed on non-Bt plants for ≥9 days and then moved to Bt plants developed to adults, and 63.6% of pairs of these adults produced viable eggs, with an average of 185 progeny per female. For SS larvae that fed on Bt plants for 1 or 2 days and then moved to non-Bt plants, few larvae developed to adults with varied emergence times, whereas 28.1 and 13.5% RS larvae feeding on Bt plants for 1 and 2 days, respectively, successfully developed to adults; 43.8% of pairs of these adults produced viable eggs, with an average of 220 progeny per female. For the case of the single Bt gene maize plants (event MON 810), the results suggest that RS insects may have advantages in survival and reproduction over SS if RS larvae hatch and feed on Bt plants during the first 1 or 2 days and then move to non-Bt plants. This advantage is less for RS larvae that hatch and feed on non-Bt plants first and then move to Bt plants, unless the larval movement occurs in the later stages (e.g., fourth or fifth instars).

Sugarcane borer, Diatraea saccharalis (Fabricius) (Lepidoptera: Crambidae), is a key insect pest that affects crop yield in Mexico. Immature stages of the pest are naturally attacked by a complex of parasitoids. We identified the parasitoid Siphosturmia rafaeli (Townsend) to be a new record at Tabasco, Mexico, and reported a new host.

We present the development of a genomic library using RADseq (restriction site associated DNA sequencing) protocol for marker discovery that can be applied on evolutionary studies of the sugarcane borer Diatraea saccharalis, an important South American insect pest. A RADtag protocol combined with Illumina paired-end sequencing allowed de novo discovery of 12 811 SNPs and a high-quality assembly of 122.8M paired-end reads from six individuals, representing 40 Gb of sequencing data. Approximately 1.7 Mb of the sugarcane borer genome distributed over 5289 minicontigs were obtained upon assembly of second reads from first reads RADtag loci where at least one SNP was discovered and genotyped. Minicontig lengths ranged from 200 to 611 bp and were used for functional annotation and microsatellite discovery. These markers will be used in future studies to understand gene flow and adaptation to host plants and control tactics.

Peptidase inhibitors (PIs) are essential proteins involved in plant resistance to herbivorous insects, yet many insect species are able to escape the negative effects of these molecules. We compared the effects of acute and chronic ingestion of soybean peptidase inhibitors (SPIs) on Spodoptera frugiperda and Diatraea saccharalis, two Lepidoptera species with different sensitivities to SPI ingestion. We analyzed the trypsin and chymotrypsin gene expression profiles in both species. Acute exposure of S. frugiperda to the inhibitors activated seven genes (SfChy5, SfChy9, SfChy19, SfChy22, SfTry6, SfTry8, and SfTry10), whereas chronic exposure activated 16 genes (SfChy2, SfChy4, SfChy5, SfChy8, SfChy9, SfChy11, SfChy12, SfChy15, SfChy17, SfChy21, SfChy22, SfTry6, SfTry8, SfTry9, SfTry10, and SfTry12). By contrast, the challenge of D. saccharalis with SPIs did not differentially induce the expression of trypsin- or chymotrypsin-encoding genes, with the exception of DsChy7. Bayesian phylogenetic analysis of S. frugiperda trypsin protein sequences revealed two gene clades: one composed of genes responsive to the SPIs and a second composed of the unresponsive genes. D. saccharalis trypsin proteins were clustered nearest to the S. frugiperda unresponsive genes. Overall, our findings support a hypothesized mechanism of resistance of Noctuidae moths to SPIs, involving gene number expansion of trypsin and chymotrypsin families and regulation of gene expression, which could also explain the variable susceptibility between S. frugiperda and D. saccharalis to these plant inhibitors.

Insects are organisms extremely well adapted to diverse habitats, primarily due to their innate immune system, which provides them with a range of cellular and humoral responses against microorganisms. Lepidoptera hemolymph proteins involved in humoral responses are well known; however, there is a lack of knowledge about the sugarcane borer Diatraea saccharalis. In this present work, the hemolymph proteins of this pest insect were studied by applying proteomic methodologies. Two-dimensional electrophoresis (2-DE) gels of proteins extracted from naive larvae and larvae challenged with Escherichia coli (ATCC 11224) and Bacillus subtilis (ATCC 6623) showed an average of 300 spots, and 92 of these spots corresponded in all three 2-DE gels. Forty-one spots were excised and digested with trypsin and analyzed using mass spectrometry. After analysis, 10 proteins were identified, including some proteins of the immune system: β-defensin-like protein, Turandot A-like protein, attacin-like protein, peptidoglycan recognition protein and cyclophilin-like protein. Nine proteins were present in both experimental conditions; however, β-defensin-like protein was present only in hemolymph challenged by B. subtilis. Notably, attacin-like protein was strongly induced by challenge with E. coli, suggesting an immune response against the infection. However, antimicrobial activity was observed in the test zone of microbial growth inhibition of B. subtilis solely with the hemolymph extract of the larvae challenged with B. subtilis. We made for the first time a proteomic profile of the hemolymph of D. saccharalis in which it was possible to identify the presence of important proteins involved in the immune response.