Gilberto Santos Andrade

Estimativa de Trichogramma pretiosum para controle de Tuta absoluta em tomateiro estaqueado

The objective of this work was to estimate the ideal number of Trichogramma pretiosum Riley to be released in field for the tomato leafminer control Tuta absoluta (Meyrick). An experiment was carried out in a greenhouse, in which tomato plants with 60 days, after the transplantation, were infested with 200 eggs of Anagasta kuehniella (Zeller), an alternative host, in the subsequent ratios: 70% of eggs were put on the top of the plants, 24% on the medium height and 6% on the very bottom of the plants. Females of T. pretiosum were released following the ratios of 1, 2, 4, 8, 16 and 32 parasitoids per host egg. Independently of the three distinct plant parts (top, medium or bottom), the ratio of 16 parasitoids per host egg delivered the best results. This ratio value was closer to the ideal number for field releasing in commercial crop production of stalked tomato, aiming the tomato leafminer control.

Immunity of an Alternative Host Can Be Overcome by Higher Densities of Its Parasitoids Palmistichus elaeisis and Trichospilus diatraeae

Interactions of the parasitoids Palmistichus elaeisis Delvare & LaSalle and Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae) with its alternative host Anticarsia gemmatalis (Hübner) (Lepidoptera: Noctuidae) affect the success or failure of the mass production of these parasitoids for use in integrated pest management programs. The aim of this study was to evaluate changes in the cellular defense and encapsulation ability of A. gemmatalis pupae against P. elaeisis or T. diatraeae in adult parasitoid densities of 1, 3, 5, 7, 9, 11 or 13 parasitoids/pupae. We evaluated the total quantity of circulating hemocytes and the encapsulation rate versus density. Increasing parasitoid density reduced the total number of hemocytes in the hemolymph and the encapsulation rate by parasitized pupae. Furthermore, densities of P. elaeisis above 5 parasitoids/pupae caused higher reduction in total hemocyte numbers. The encapsulation rate fell with increasing parasitoid density. However, parasitic invasion by both species induced generally similar responses. The reduction in defensive capacity of A. gemmatalis is related to the adjustment of the density of these parasitoids to their development in this host. Thus, the role of the density of P. elaeisis or T. diatraeae by pupa is induced suppression of cellular defense and encapsulation of the host, even without them possesses a co-evolutionary history. Furthermore, these findings can predict the success of P. elaeisis and T. diatraeae in the control of insect pests through the use of immunology as a tool for evaluation of natural enemies.

Reproductive biology of Palmistichus elaeisis (Hymenoptera: Eulophidae) with alternative and natural hosts

Mass rearing of parasitoids depends on choosing appropriate alternative hosts. The objective of this study was to select alternative hosts to rear the parasitoid Palmistichus elaeisis Delvare & LaSalle, 1993 (Hymenoptera: Eulophidae). Pupae of the lepidopterans Anticarsia gemmatalis Hubner, 1818 (Lepidoptera: Noctuidae), Bombyx mori Linnaeus, 1758 (Lepidoptera: Bombycidae) and Thyrinteina arnobia (Stoll, 1782) (Lepidoptera: Geometridae) were exposed to parasitism by females of P. elaeisis. The duration of the life cycle of P. elaeisis was 21.60 ± 0.16 and 24.15 ± 0.65 days on pupae of A. gemmatalis and B. mori, respectively, with 100.0% parasitism of the pupae and 71.4 and 100.0% emergence of parasitoids from the first and second hosts, respectively. The offspring number of P. elaeisis was 511.00 ± 49.70 and 110.20 ± 19.37 individuals per pupa of B. mori and A. gemmatalis, respectively. The reproduction of P. elaeisis from pupae of T. arnobia after six generations was similar to the other hosts.

CARACTERÍSTICAS BIOLÓGICAS DE TRICHOGRAMMA EXIGUUM EM OVOS DE ANAGASTA KUEHNIELLA E SITOTROGA CEREALELLA

O objetivo deste trabalho foi obter informacoes sobre alguns aspectos biologicos de Trichogramma exiguum Pinto & Platiner, (Hymenoptera: Trichogrammatidae) criado nos hospedeiros alternativos Anagasta kuehniella Zeller (Lepidoptera: Pyralidae) e Sitotroga cerealella Oliver (Lepidoptera: Gelechiidae), visando a producao desses parasitoides para utilizacao no controle biologico de pragas. A maior taxa de parasitismo de T. exiguum foi encontrada em ovos de A. kuehniella. A viabilidade foi superior em ovos de S. cerealella. A razao sexual foi semelhante para ambos os hospedeiros alternativos. Estes resultados demonstram que ambos hospedeiros alternativos podem ser utilizados na criacao massal de T. exiguum, porem levando em consideracao a importância da taxa de parasitismo, A. kuehniella demonstrou maior aptidao.

Side Effects of Fungicides Used in Cucurbitaceous Crop on Trichogrammaatopovirilia Oatman & Platner (Hymenoptera: Trichogramatidae)

Trichogramma spp. (Hymenoptera: Trichogrammatidae) can control Diaphania hyalinata Linnaeus (Lepidoptera: Pyralidae). On the other hand, pesticides may reduce the efficiency of natural enemies. The objective was to evaluate the side-effects of fungicides used in the production of cucurbitaceous crops on Trichogramma atopovirilia Oatman & Platner parasitizing D. hyalinata eggs. The fungicides used in bioassays were: azoxystrobin (0.08 g active ingredient [ai] L -1 ), chlorothalonil (2.00 g ai L -1 ), mancozeb (1.60 g ai L -1 ), tebuconazole (0.25 g ai L -1 ) and thiophanate-methyl (0.49 g ai L -1 ). Cardboards with 30 D. hyalinata eggs previously immersed in fungicide solutions and distilled water (control) were offered separately to 20 newly emerged T. atopovirilia females in glass tubes. Parasitism, parasitism reduction, emergence, sex ratio, and number of individuals per egg were evaluated. The fungicides chlorothalonil, thiophanate-methyl and tebuconazole reduced parasitism of T. atopovirilia by 43.37, 27.64 and 18.51%, respectively. However, parasitism with azoxystrobin (79.21%) was higher than the control (67.37%) (P ≤ 0.05). Chlorothalonil, thiophanate-methyl and tebuconazole reduced emergence by 73.77, 75.62 and 79.35% (P ≤ 0.05), respectively. Azoxystrobin and thiophanate-methyl reduced the sex ratio by 0.77 and 0.76 (P ≤ 0.05), respectively. Fungicides did not reduce the number of individuals per egg. The fungicides azoxystrobin and mancozeb were selective for T. atopovirilia for most studied parameters suggesting that these products must have the priority in crop disease management to allow efficient biological control of T. atopovirilia against D. hyalinata.

DESENVOLVIMENTO E REPRODUÇÃO DE PODISUS NIGRISPINUS (HETEROPTERA: PENTATOMIDAE) ALIMENTADO COM LAGARTAS DE HELIOTHIS VIRESCENS (LEPIDOPTERA: NOCTUIDAE)

Heliothis virescens (Fabr.) (Lepidoptera: Noctuidae) e um inseto polifago amplamente distribuido no continente americano, onde o controle quimico e a tatica mais utilizada. Os impactos de seu uso tornam necessaria a busca de alternativas de manejo desse inseto-praga. Assim, este trabalho teve por objetivo avaliar o desenvolvimento e a reproducao de Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) com lagartas de H. virescens, comparado a alimentacao com pupas de Tenebrio molitor L. (Coleoptera: Tenebrionidae). O experimento foi conduzido em sala climatizada a 25 ± 1 oC, 70 ± 15% de umidade relativa e 14 horas de fotofase. O delineamento foi o inteiramente casualizado com 50 e 20 repeticoes nas etapas I e II, respectivamente. O desenvolvimento ninfal desse predador foi semelhante com essas presas, mas o numero de posturas, ovos e ninfas por femea, alem do intervalo entre posturas de P. nigrispinus apresentaram melhores resultados com T. molitor. Assim, P. nigrispinus apresentou desenvolvimento ninfal satisfatorio com lagartas de H. virescens, mas o sucesso reprodutivo foi melhor quando recebeu T. molitor como presa.

OCORRÊNCIA DE PARASITÓIDES ASSOCIADOS À BROCA-DO-CAFÉ NO SUL DO ESPÍRITO SANTO-BRASIL

O objetivo deste trabalho foi verificar a ocorrencia de insetos parasitoides, da broca-do-cafe, Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae) em plantios de cafe no Sul do Estado do Espirito Santo. Os parasitoides encontrados foram Prorops nasuta (Hym.: Bethilidae) e Cephalonomia stephanoderis (Hym.: Bethilidae), com niveis de parasitismo de ate 33%. A presenca destes inimigos naturais sugere um potencial de regulacao natural de H. hampei, e perspectivas para utilizacao em programas de Manejo Integrado de Pragas.

Selection of native isolates of Beauveria bassiana (Ascomycota, Hypocreales) for the control of the coffee borer beetle Hypothenemus hampei (Scolytinae) in Brazil

Selection of native isolates of Beauveria bassiana (Ascomycota, Hypocreales) for the control of the coffee borer beetle Hypothenemus hampei (Scolytinae) in Brazil Hypothenemus hampei (coffee borer beetle or coffee berry borer) is the main pest of coffee Coffea spp. in the world. The aim of this study was to select native isolates of the ascomycete Beauveria bassiana for biological control of this pest. We collected 27 isolates on H. hampei from the state of Espírito Santo in Brazil. Isolates CCA-UFES/Bb-15, Bb-11, Bb-4 and Bb-18 were selected, with confirmed beetle mortality of > 60% after spraying with a suspension of 105 conidia/mL. The median lethal concentration (LC50) of these isolates varied from 4.0 × 104 to 7.9 × 104 conidia/mL. The standard isolate (ESALQ-447) showed the highest conidiogenesis, with 8.5 × 106 conidia, followed by CCA-UFES/Bb-18, Bb-11, Bb-15 and Bb-4, all exceeding 4 × 106. Isolates CCA-UFES/Bb-4, Bb-11, Bb-15, and Bb-18 have a potential to control H. hampei.

INFLUÊNCIA DA DENSIDADE DE OVOS DE Spodoptera frugiperda EM ALGUNS ASPECTOS BIOLÓGICOS DE TRÊS ESPÉCIES DE Trichogramma

O objetivo do presente trabalho foi determinar as isotermas de sorcao das espigas de milho para diversas condicoes de temperatura e umidade relativa do ar e ajustar diferentes modelos matematicos aos dados experimentais. Para obtencao do teor de agua de equilibrio higroscopico das espigas de milho foi utilizado o metodo estatico, em câmaras com temperatura controlada, contendo no seu interior dessecadores com solucoes salinas saturadas. A temperatura variou entre 10 e 50°C e a umidade relativa entre 0,11 e 0,84 (decimal). As amostras foram pesadas periodicamente, sendo o equilibrio higroscopio alcancado quando a variacao da massa das amostras foi igual ou inferior a 0,01 g. Os modelos matematicos recomendados pela ASAE foram ajustados as dados experimentais. Para a avaliacao do grau de ajuste de cada modelo considerou-se a magnitude do coeficiente de determinacao ajustado, erros medio relativo e estimado, e a verificacao do comportamento da distribuicao dos residuos. Conclui-se que a higroscopicidade da espiga de milho segue a mesma tendencia da maioria dos produtos agricolas e que os modelos de Chung-Pfost Modificado, Halsey Modificado e Oswin Modificado representam adequadamente o fenomeno.

Reproduction of Trichospilus diatraeae (Hymenoptera: Eulophidae) with Different Densities and Parasitism Periods in Anticarsia gemmatalis (Lepidoptera: Noctuidae) Pupae

Mass production of the endoparasitoid Trichospilus diatraeae Cherian & Margabandhu (Hymenoptera: Eulophidae) should be studied to allow its use in the biological control of Lepidoptera pests. The objective of this study was to evaluate the reproduction of T. diatraeae with Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) pupae with different host densities and parasitism periods in the laboratory. The experiment had 12 24/48-hour old A. gemmatalis pupae per replication individualized and exposed to 1:1, 3:1, 6:1, 9:1, 12:1, or 15:1 parasitoids/host densities for 12, 24, 48, or 72 hours, respectively, in a climatized chamber at 25 ± 2 °C, 70 ± 10% relative humidity and 14 hour photophase. Parasitoid emergence increased up to 10 parasitoids/host. Parasitoid life cycle (egg-adult) was shorter and parasitism percentage increased as parasitoid density and parasitism period increased. Increasing female parasitoid density reduced the sex ratio, but parasitism period did not affect this parameter. The combination of 10 parasitoids/pupa during 24 hours should be used for T. diatraeae reproduction.