Virulence of entomopathogenic nematodes and their symbiotic bacteria, under laboratory conditions, aiming controlling Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) on sugarcane / Virulência de nematoides entomopatogênicos e suas bactérias simbióticas, sob condições de laboratório, visando controlar Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) na cana-de-açúcar

Sugarcane crops Saccharum spp. (Poales: Poaceae) produces different derivatives to the world: sugar, ethanol and bioenergy. Despite the application of pesticides, insect pests still cause economic losses, among these the pink sugarcane mealybug Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) causing direct and indirect damage to the plant. This study assess the virulence of three entomopathogenic nematodes (EPNs) species and their symbiont bacteria against the pink sugarcane mealybug, under laboratory conditions. Fourteen treatments represented by control (distilled water), Heterorhabditis bacteriophora Poinar, 1976 (HB EN01) (Rhabditida: Heterorhabditidae), Steinernema rarum (Doucet, 1986) (PAM25) and Steinernema carpocapsae Weiser, 1955 (All) (Rhabditida: Steinermatidae) at concentrations of 25, 50, 75 and 100 infective juveniles (IJs)/insect, and the standard chemical product, thiamethoxam, were assayed. In a second experiment, the bacteria Photorhabdus luminescens (Thomas and Poinar, 1979), Xenorhabdus szentirmaii Lengyel, 2005 and Xenorhabdus nematophila (Poinar and Thomas, 1965) (Enterobacterales: Morganellaceae) at 3.0 x 109 cells/ml were assessed for each treatment. Ten replications were stablished, each one counting ten females/mealybugs inside a 10 cm Petri dish, amounting 100 individuals/treatment. All treatments were kept under stable conditions (25±1 ºC, H 70±10%, in the dark). All nematodes species infected S. sacchari. Steinerma rarum (PAM25) provided the highest mortality against the pink sugarcane mealybug (79.25%), followed by H. bacteriophora (HB EN01) (58.25%) and S. carpocapsae (All) (42.50%) (P<0.001). The mortality rate caused by X. szentirmaii, P. luminescens and X. nematophila were 40, 45 and 20%, respectively. Steinerma rarum (PAM25) has conditions to be a potential agent to be incorporate into the integrated pest management in sugarcane.

A cultura da cana-de-açúcar Saccharum spp. (Poales: Poaceae) produz diferentes derivados para o mundo: açúcar, etanol e bioenergia. Apesar da aplicação de pesticidas, os insetos-praga ainda causam prejuízos econômicos, dentre eles a cochonilha rosada da cana-de-açúcar Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) causando danos diretos e indiretos à planta. Este estudo avaliou a virulência de três espécies de nematoides entomopatogênicos (NEPs) e suas bactérias simbiontes contra a cochonilha rosada da cana-de-açúcar, em condições de laboratório. Quatorze tratamentos representados pelo controle (água destilada), Heterorhabditis bacteriophora Poinar, 1976 (HB EN01) (Rhabditida: Heterorhabditidae), Steinernema rarum (Doucet, 1986) (PAM25) e Steinernema carpocapsae Weiser, 1955 (All) (Rhabditida: Steinermatidae) nas concentrações de 25, 50, 75 e 100 juvenis infectantes (JIs)/inseto, e o produto químico padrão, tiametoxam, foram testados. Em um segundo experimento, a bactéria Photorhabdus luminescens (Thomas e Poinar, 1979), Xenorhabdus szentirmaii Lengyel, 2005 e Xenorhabdus nematophila (Poinar e Thomas, 1965) (Enterobacterales: Morganellaceae) em 3,0 x 109 células/ml foram avaliadas para cada tratamento. Dez repetições foram estabelecidas, cada uma contendo dez fêmeas/cochonilhas dentro de uma placa de Petri de 10 cm, totalizando 100 indivíduos/tratamento. Todos os tratamentos foram mantidos em condições estáveis (25±1 ºC, U 70±10%, no escuro). Todas as espécies de nematoides infectaram S. sacchari. Steinerma rarum (PAM25) proporcionou a maior mortalidade contra a cochonilha rosada da cana-de-açúcar (79,25%), seguida por H. bacteriophora (HB EN01) (58,25%) e S. carpocapsae (All) (42,50%) (P<0,001). As taxas de mortalidade causada por X. szentirmaii, P. luminescens e X. nematophila foram de 40, 45 e 20%, respectivamente. Steinerma rarum (PAM25) tem condições de ser um agente potencial a ser incorporado ao manejo integrado de pragas da cana-de-açúcar.

Phenotypic plasticity in adults of Anticarsia gemmatalis exposed to sub-doses of Bt-based bioinsecticide / Plasticidade fenotípica morfométrica em adultos de Anticarsia gemmatalis Hübner, 1818 expostos a subdoses de Bacillus thuringiensis Berliner, 1911

Anticarsia gemmatalis Hünber, 1818 is one of the main defoliating species in the soybean crop. Bacillus thuringiensis Berliner, 1915, is a bacterium used in the biological control of this pest species. Resistant populations and their sublethal effects caused by the use of the bacteria have already been reported; however, there are no studies on phenotypic plasticity in adulthood exposed to Bt-based bioinsecticide sub-doses. This study aimed to evaluate the morphometry of A. gemmatalis adults under laboratory conditions submitted to the Bt-based bioinsecticide Dipel® over the three generations. The body segments mensuread were width, length, and area of the anterior and posterior wings, the weight of the integument, chest, abdomen, wings, and the whole adult of males and females. Among the treatments, LC5 in the first generation and LC10 in the second generation were those with lower thresholds in relation to the weight of the chest and abdomen, considering the proportions of the body smaller than the females. The female's weight adulthood was reduced by 10% about males, and, only in the first generation. Males have larger body size and more pronounced phenotypic plasticity than females. Here, we demonstrate the first study assessing the phenotypic plasticity of A. gemmatalis adults.

Anticarsia gemmatalis Hünber, 1818 é uma das principais espécies desfolhadoras da cultura da soja. Bacillus thuringiensis Berliner, 1915, é uma bactéria utilizada no controle biológico dessa espécie de praga. Populações resistentes e seus efeitos subletais causados pelo uso da bactéria já foram relatados, no entanto, não há estudos sobre a plasticidade fenotípica na idade adulta exposta a subdoses de bioinseticida à base de Bt. Este trabalho teve como objetivo avaliar a morfometria de adultos de A. gemmatalis em condições de laboratório submetidos ao bioinseticida Dipel® ao longo de três gerações. Os segmentos corporais mensuráveis eram largura, comprimento e área das asas anterior e posterior, o peso do tegumento, tórax, abdômen, asas e todo o adulto de machos e fêmeas. Dentre os tratamentos, CL5 na primeira geração e CL10 na segunda geração foram aqueles com limiares mais baixos em relação ao peso do tórax e abdômen, considerando as proporções do corpo menores que as do sexo feminino. O peso da fêmea na idade adulta foi reduzido em 10% em relação aos machos e, apenas na primeira geração. Os machos têm tamanho corporal maior e plasticidade fenotípica mais pronunciada do que as fêmeas. Este estudo demonstra o primeiro estudo avaliando a plasticidade fenotípica de adultos de A. gemmatalis.

Virulence of entomopathogenic nematodes and their symbiotic bacteria, under laboratory conditions, aiming controlling Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) on sugarcane

Abstract Sugarcane crops Saccharum spp. (Poales: Poaceae) produces different derivatives to the world: sugar, ethanol and bioenergy. Despite the application of pesticides, insect pests still cause economic losses, among these the pink sugarcane mealybug Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) causing direct and indirect damage to the plant. This study assess the virulence of three entomopathogenic nematodes (EPNs) species and their symbiont bacteria against the pink sugarcane mealybug, under laboratory conditions. Fourteen treatments represented by control (distilled water), Heterorhabditis bacteriophora Poinar, 1976 (HB EN01) (Rhabditida: Heterorhabditidae), Steinernema rarum (Doucet, 1986) (PAM25) and Steinernema carpocapsae Weiser, 1955 (All) (Rhabditida: Steinermatidae) at concentrations of 25, 50, 75 and 100 infective juveniles (IJs)/insect, and the standard chemical product, thiamethoxam, were assayed. In a second experiment, the bacteria Photorhabdus luminescens (Thomas and Poinar, 1979), Xenorhabdus szentirmaii Lengyel, 2005 and Xenorhabdus nematophila (Poinar and Thomas, 1965) (Enterobacterales: Morganellaceae) at 3.0 x 109 cells/ml were assessed for each treatment. Ten replications were stablished, each one counting ten females/mealybugs inside a 10 cm Petri dish, amounting 100 individuals/treatment. All treatments were kept under stable conditions (25±1 ºC, H 70±10%, in the dark). All nematodes species infected S. sacchari. Steinerma rarum (PAM25) provided the highest mortality against the pink sugarcane mealybug (79.25%), followed by H. bacteriophora (HB EN01) (58.25%) and S. carpocapsae (All) (42.50%) (P 0.001). The mortality rate caused by X. szentirmaii, P. luminescens and X. nematophila were 40, 45 and 20%, respectively. Steinerma rarum (PAM25) has conditions to be a potential agent to be incorporate into the integrated pest management in sugarcane.

Resumo A cultura da cana-de-açúcar Saccharum spp. (Poales: Poaceae) produz diferentes derivados para o mundo: açúcar, etanol e bioenergia. Apesar da aplicação de pesticidas, os insetos-praga ainda causam prejuízos econômicos, dentre eles a cochonilha rosada da cana-de-açúcar Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) causando danos diretos e indiretos à planta. Este estudo avaliou a virulência de três espécies de nematoides entomopatogênicos (NEPs) e suas bactérias simbiontes contra a cochonilha rosada da cana-de-açúcar, em condições de laboratório. Quatorze tratamentos representados pelo controle (água destilada), Heterorhabditis bacteriophora Poinar, 1976 (HB EN01) (Rhabditida: Heterorhabditidae), Steinernema rarum (Doucet, 1986) (PAM25) e Steinernema carpocapsae Weiser, 1955 (All) (Rhabditida: Steinermatidae) nas concentrações de 25, 50, 75 e 100 juvenis infectantes (JIs)/inseto, e o produto químico padrão, tiametoxam, foram testados. Em um segundo experimento, a bactéria Photorhabdus luminescens (Thomas e Poinar, 1979), Xenorhabdus szentirmaii Lengyel, 2005 e Xenorhabdus nematophila (Poinar e Thomas, 1965) (Enterobacterales: Morganellaceae) em 3,0 x 109 células/ml foram avaliadas para cada tratamento. Dez repetições foram estabelecidas, cada uma contendo dez fêmeas/cochonilhas dentro de uma placa de Petri de 10 cm, totalizando 100 indivíduos/tratamento. Todos os tratamentos foram mantidos em condições estáveis (25±1 ºC, U 70±10%, no escuro). Todas as espécies de nematoides infectaram S. sacchari. Steinerma rarum (PAM25) proporcionou a maior mortalidade contra a cochonilha rosada da cana-de-açúcar (79,25%), seguida por H. bacteriophora (HB EN01) (58,25%) e S. carpocapsae (All) (42,50%) (P 0,001). As taxas de mortalidade causada por X. szentirmaii, P. luminescens e X. nematophila foram de 40, 45 e 20%, respectivamente. Steinerma rarum (PAM25) tem condições de ser um agente potencial a ser incorporado ao manejo integrado de pragas da cana-de-açúcar.

Phenotypic plasticity in adults of Anticarsia gemmatalis exposed to sub-doses of Bt-based bioinsecticide

Abstract Anticarsia gemmatalis Hünber, 1818 is one of the main defoliating species in the soybean crop. Bacillus thuringiensis Berliner, 1915, is a bacterium used in the biological control of this pest species. Resistant populations and their sublethal effects caused by the use of the bacteria have already been reported; however, there are no studies on phenotypic plasticity in adulthood exposed to Bt-based bioinsecticide sub-doses. This study aimed to evaluate the morphometry of A. gemmatalis adults under laboratory conditions submitted to the Bt-based bioinsecticide Dipel® over the three generations. The body segments mensuread were width, length, and area of the anterior and posterior wings, the weight of the integument, chest, abdomen, wings, and the whole adult of males and females. Among the treatments, LC5 in the first generation and LC10 in the second generation were those with lower thresholds in relation to the weight of the chest and abdomen, considering the proportions of the body smaller than the females. The females weight adulthood was reduced by 10% about males, and, only in the first generation. Males have larger body size and more pronounced phenotypic plasticity than females. Here, we demonstrate the first study assessing the phenotypic plasticity of A. gemmatalis adults.

Resumo Anticarsia gemmatalis Hünber, 1818 é uma das principais espécies desfolhadoras da cultura da soja. Bacillus thuringiensis Berliner, 1915, é uma bactéria utilizada no controle biológico dessa espécie de praga. Populações resistentes e seus efeitos subletais causados pelo uso da bactéria já foram relatados, no entanto, não há estudos sobre a plasticidade fenotípica na idade adulta exposta a subdoses de bioinseticida à base de Bt. Este trabalho teve como objetivo avaliar a morfometria de adultos de A. gemmatalis em condições de laboratório submetidos ao bioinseticida Dipel® ao longo de três gerações. Os segmentos corporais mensuráveis eram largura, comprimento e área das asas anterior e posterior, o peso do tegumento, tórax, abdômen, asas e todo o adulto de machos e fêmeas. Dentre os tratamentos, CL5 na primeira geração e CL10 na segunda geração foram aqueles com limiares mais baixos em relação ao peso do tórax e abdômen, considerando as proporções do corpo menores que as do sexo feminino. O peso da fêmea na idade adulta foi reduzido em 10% em relação aos machos e, apenas na primeira geração. Os machos têm tamanho corporal maior e plasticidade fenotípica mais pronunciada do que as fêmeas. Este estudo demonstra o primeiro estudo avaliando a plasticidade fenotípica de adultos de A. gemmatalis.

Phenotypic plasticity in adults of Anticarsia gemmatalis exposed to sub-doses of Bt-based bioinsecticide.

Anticarsia gemmatalis Hünber, 1818 is one of the main defoliating species in the soybean crop. Bacillus thuringiensis Berliner, 1915, is a bacterium used in the biological control of this pest species. Resistant populations and their sublethal effects caused by the use of the bacteria have already been reported; however, there are no studies on phenotypic plasticity in adulthood exposed to Bt-based bioinsecticide sub-doses. This study aimed to evaluate the morphometry of A. gemmatalis adults under laboratory conditions submitted to the Bt-based bioinsecticide Dipel® over the three generations. The body segments mensuread were width, length, and area of the anterior and posterior wings, the weight of the integument, chest, abdomen, wings, and the whole adult of males and females. Among the treatments, LC5 in the first generation and LC10 in the second generation were those with lower thresholds in relation to the weight of the chest and abdomen, considering the proportions of the body smaller than the females. The female's weight adulthood was reduced by 10% about males, and, only in the first generation. Males have larger body size and more pronounced phenotypic plasticity than females. Here, we demonstrate the first study assessing the phenotypic plasticity of A. gemmatalis adults.

Virulence of entomopathogenic nematodes and their symbiotic bacteria, under laboratory conditions, aiming controlling Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) on sugarcane.

Sugarcane crops Saccharum spp. (Poales: Poaceae) produces different derivatives to the world: sugar, ethanol and bioenergy. Despite the application of pesticides, insect pests still cause economic losses, among these the pink sugarcane mealybug Saccharicoccus sacchari (Cockerell, 1895) (Hemiptera: Pseudococcidae) causing direct and indirect damage to the plant. This study assess the virulence of three entomopathogenic nematodes (EPNs) species and their symbiont bacteria against the pink sugarcane mealybug, under laboratory conditions. Fourteen treatments represented by control (distilled water), Heterorhabditis bacteriophora Poinar, 1976 (HB EN01) (Rhabditida: Heterorhabditidae), Steinernema rarum (Doucet, 1986) (PAM25) and Steinernema carpocapsae Weiser, 1955 (All) (Rhabditida: Steinermatidae) at concentrations of 25, 50, 75 and 100 infective juveniles (IJs)/insect, and the standard chemical product, thiamethoxam, were assayed. In a second experiment, the bacteria Photorhabdus luminescens (Thomas and Poinar, 1979), Xenorhabdus szentirmaii Lengyel, 2005 and Xenorhabdus nematophila (Poinar and Thomas, 1965) (Enterobacterales: Morganellaceae) at 3.0 x 109 cells/ml were assessed for each treatment. Ten replications were stablished, each one counting ten females/mealybugs inside a 10 cm Petri dish, amounting 100 individuals/treatment. All treatments were kept under stable conditions (25±1 ºC, H 70±10%, in the dark). All nematodes species infected S. sacchari. Steinerma rarum (PAM25) provided the highest mortality against the pink sugarcane mealybug (79.25%), followed by H. bacteriophora (HB EN01) (58.25%) and S. carpocapsae (All) (42.50%) (P<0.001). The mortality rate caused by X. szentirmaii, P. luminescens and X. nematophila were 40, 45 and 20%, respectively. Steinerma rarum (PAM25) has conditions to be a potential agent to be incorporate into the integrated pest management in sugarcane.

Potential of Entomopathogenic Fungi as Biological Control Agents of Diamondback Moth (Lepidoptera: Plutellidae) and Compatibility With Chemical Insecticides.

The objectives were to evaluate the efficiency of entomopathogenic fungi against Plutella xylostella (L.) and the compatibility of the most virulent isolates with some of the insecticides registered for use on cabbage crops. Pathogenicity tests used isolates of Beauveria bassiana, Metarhizium rileyi, Isaria fumosorosea, Isaria sinclairii, and Lecanicillium muscarium standardized at a concentration of 10(7) conidia/ml. Cabbage leaf discs were immersed in these suspensions, and after evaporation of the excess water, were placed 10 second-instar larvae of P. xylostella, totaling 10 leaf discs per treatment. Mortality was assessed 7 d after treatment, and the isolates that caused mortality>80% were used to estimate LC50 and LT50. The compatibilities of the most virulent isolates and the insecticides were tested from the mixture of these into the culture medium, and after solidifying, the medium was inoculated with an aliquot of the isolated suspension. The following parameters were evaluated: growth of the colony, number and viability of conidia after 7 d. The isolated IBCB01, IBCB18, IBCB66, and IBCB87 of B. bassiana, LCMAP101 of M. rileyi, and ARSEF7973 of I. sinclairii caused mortality between 80 and 100%, with LC50 and LT50 between 2.504 to 6.775×10(4) conidia/ml and 52.22 to 112.13 h, respectively. The active ingredients thiamethoxam and azadirachtin were compatible with the entomopathogenic fungi. The results suggest that the use of these isolates is an important alternative in the pesticidal management of P. xylostella, with the possible exception of the associated use of chemical controls using the active ingredients thiamethoxam or azadirachtin.

Interactions Between Bt-Bioinsecticides and Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae), a Predator of Plutella xylostella (L.) (Lepidoptera: Plutellidae).

Bioinsecticides are being increasingly used to protect vegetable crops against herbivores, but data on the side effects of such strategy on the third trophic level are still required. We investigated the influence of the Bacillus thuringiensis subsp. kurstaki HD-1 strain and of the commercial bioinsecticide Agree® on the biological aspects of the predator Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) when feeding on Plutella xylostella (L.) (Lepidoptera: Plutellidae)-infected larvae. On average, infected larvae were consumed more often than the non-infected larvae throughout the predator nymphal development, and no effect on nymph survival was observed. Population growth parameters (R 0, r m, and λ) resulting from the fertility life tables did not differ among treatments. The results led to the conclusion that P. nigrispinus can be used in combination with the product Agree® or the strain HD-1 for the control of P. xylostella. The combined use of these control agents helps to maintain the balance of the ecosystem and contributes for the production of food for healthy human consumption.

Interactions between the entomopathogenic fungi Beauveria bassiana (Ascomycota: Hypocreales) and the aphid parasitoid Diaeretiella rapae (Hymenoptera: Braconidae) on Myzus persicae (Hemiptera: Aphididae).

The interactions between the entomopathogenic fungus Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Ascomycota: Hypocreales) and the aphid parasitoid Diaeretiella rapae McIntoch (Hymenoptera: Braconidae) were evaluated under laboratory conditions. Nymphs of Myzus persicae Sulzer (Hemiptera: Aphididae) were first exposed to parasitoid females for 24 h and then 0, 24, and 48 h afterwards sprayed with a solution of B. bassiana. Likewise, aphids were also sprayed with B. bassiana and then exposed to parasitoids at 0, 24, and 48 h afterwards. Parasitism rate varied from 13 to 66.5%, and were significantly lower in treatments where the two agents were exposed within a 0-24 h time interval compared with the control (without B. bassiana). Parasitoid emergence was negatively affected in treatments with B. bassiana spraying and subsequent exposure to D. rapae. Decreases in longevity of adult females of the D. rapae F1 generation were observed in treatments with B. bassiana spraying. The application of these two biological control agents can be used in combination on the control of M. persicae, wherein this use requires effective time management to avoid antagonistic interactions.

[Influence of Diaphania hyalinata (L.) (Lepidoptera: Crambidae) egg density on the parasitization capacity of Trichogramma exiguum Pinto & Platner and Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae)]. / Influência da densidade de ovos de Diaphania hyalinata (L.) (Lepidoptera: Crambidae) na capacidade de parasitismo de Trichogramma exiguum Pinto & Platner e Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae).

The effects of the egg density of Diaphania hyalinata (L.) on several biological parameters of Trichogramma exiguum Pinto & Platner and T. pretiosum Riley were investigated. For that, 24h-old egg masses were isolated in glass tubes (15 replicates; 1 egg mass = 1 replicate), and offered to parasitization by a newly-emerged female of T. pretiosum or T. exiguum 24h at the proportion of one female to 5, 10, 15, 20, 25, 30, 35 and 40 eggs of D. hyalinata. The following parameters were evaluated: number of parasitized eggs, number of individuals per egg, viability and sex ratio. Trichogramma exiguum parasitized more eggs than T. pretiosum when more than 25 eggs were available per female. The percentage of emergence was satisfactory to T. pretiosum in densities up to 15 eggs/female and up to 20 eggs/female for T. exiguum. The number of individuals per egg was not statistically different in both species except in the density of 25 eggs/female. It can be concluded that T. exiguum performed better than T. pretiosum at larger clutch sizes, as T. exiguum parasitization capacity increased as a result of the size of the host clutch size.

Seleção e caracterização molecular de Bacillus thuringiensis Berliner com atividade tóxica para Trichoplusia ni Huebner (Lepidoptera: Noctuidae) / Selection and molecular characterization of Bacillus thuringiensis Berliner with toxic activity against Trichoplusia ni Huebner (Lepidoptera: Noctuidae)

Trichoplusia ni é uma praga polífaga importante em plantios de crucíferas, soja e algodão. O presente estudo objetivou selecionar e caracterizar por método molecular isolados de Bacillus thuringiensis (Bt) com potencial para atuar com agentes de controle biológico de T. ni. Para os bioensaios de patogenicidade, uma alíquota com 3 x 108 esporos/mL de suspensão de Bt de cada isolado foi aplicada na superfície do disco de dieta artificial, previamente distribuída em placas de acrílico com 50 lagartas, distribuídas em 5 repetições. Nos bioensaios para a obtenção da CL50, apenas os isolados com 100% de mortalidade foram pré-selecionados, sendo testadas as seguintes concentrações: 102, 5 x 102, 103, 2 x 103, 4 x 103, 6 x 103, 8 x 103 esporos/mL, sendo os tratamentos compostos por 120 lagartas, distribuídas em 3 repetições. Foi feita caracterização molecular para detectar os genes cry1, cry2 e Vip para os isolados que obtiveram mortalidade acima de 95%. Os isolados HD-1 (Padrão), Bt-1043N-V, Bt-1034F, Bt-1009K, Bt-1000, Bt-969A causaram 100% de mortalidade nos testes de patogenicidade e CL50 de 1,17 x 103, 1,45 x 103, 1,46 x 103, 1,01 x 103, 9,43 x 102, 1,22 x 103, respectivamente. Não foram encontrados genes cry1, cry2 e Vip nos isolados testados, podendo outras toxinas Cry estar causando a mortalidade de T. ni, visto que os isolados testados são específicos para a ordem Lepidoptera. Estes isolados mostraram potencial para o controle de T. ni, sendo virulentos a este inseto, com potencial para serem utilizados em programa de manejo desta praga.

Trichoplusia ni is a polyphagous pest that is becoming a major pest in plantations of cruciferous crops, soybeans and cotton. This study was aimed to select and molecularly characterize efficient isolates of Bacillus thuringiensis (Bt) for the control of T. ni. For the bioassays of pathogenicity, an aliquot with a 3 x 108 spores/mL suspension of Bt of each isolate was applied on the surface of the artificial diet disk, previously distributed on acrylic plates with 50 larvae, distributed in 5 repetitions. In bioassays to obtain the LC50, only isolates with 100% mortality were preselected, and tests were carried out at the concentrations 102, 5 x 102, 103, 2 x 103, 4 x 103, 6 x 103, and 8 x 103 spores/mL, and the treatments consisting of 120 larvae, distributed in 3 repetitions. A molecular characterization was performed to detect the genes cry1, cry2 and Vip for the isolates which obtained mortality over 95%. Isolates HD-1 (Standard), Bt-1043N-V, Bt-1034F, Bt-1009K, Bt-1000 and Bt-969A caused 100% mortality in the test for pathogenicity and presented an LC50 of 1.17 x 103, 1.45 x 103, 1, 46 x 103, 1.01 x 103, 9.43 x 102, 1.22 x 103, respectively. Genes cry1, cry2 and Vip were not found in the isolates tested, and other Cry toxins may have been causing the mortality of T. ni, since the isolates tested are specific for the Lepidoptera order. These isolates showed potential for the control of T. ni, being aggressive to this insect, with a potential to be used in a pest management program for this species.

Ocorrência de Lixophaga sp. (Diptera: Tachinidae) parasitando lagartas de Diaphania nitidalis (L) (Lepidoptera: Crambidae) em Cucurbita moschata no Brasil / Occurrence of Lixophaga sp. (Diptera: Tachinidae) parasitizing larvae of Diaphania nitidalis (L) (Lepidoptera: Crambidae) in Cucurbita moschata in Brazil

O parasitoide Lixophaga sp. (Diptera: Tachinidae) ocorreu em lagartas de Diaphania nitidalis (Cramer, 1782) (Lepidoptera: Crambidae) em plantio comercial de abóbora no Estado do Espírito Santo, Brasil. Não há registro de Lixophaga sp. parasitando Diaphania sp. na América do Sul e mesmo os registros para hospedeiros deste gênero são poucos. A caracterização morfológica dos adultos foi feita no Departamento e Zoologia, Instituto de Biociências da Universidade de São Paulo, Brasil. Das lagartas coletadas em campo, 26,2% estavam parasitadas, obtendo-se uma média de 2,2 pupas por lagarta e viabilidade de 14,3%. Esse parasitoide mostrou ter potencial para o controle de D. nitidalis.

The parasitoid Lixophaga sp. (Diptera: Tachinidae) occurred in larvae of Diaphania nitidalis (Cramer, 1782) (Lepidoptera: Crambidae) in a commercial pumpkin plantation in the State of Espírito Santo, Brazil. This is the first report of Lixophaga sp. parasitizing Diaphania sp. in the South America, and there are few reports concerning hosts of this genus. The morphologic characterization of the adults was made at the Department of Zoology, Institute of Bioscience, of the University of São Paulo, Brazil. Of the larvae collected in the field, 26.2% were parasitized, with an average of 2.2 pupae per larva and a viability of 14.3%. This parasitoid presented potential for the control of D. nitidalis.