Abstract Helicoverpa gelotopoeon is an endemic pest of South America that affects soybean and other important crops. Life tables are a fundamental tool used to study insect populations, resulting in crucial information for integrated pest management programs. Therefore, the aim of this study was to evaluate the biotic potential and the construction of a life table of this species under laboratory conditions. The biological parameters that showed significant differences between male and female were pupal duration, longevity and life span, which were all longer in duration for males. The net reproductive rate (R0) was 95.49, the mean generation time (T) 37.53, and the instantaneous rate of population increase “r” 0.12. The population doubling time (DT) was 5.70 days, and the daily finite rate of increase (λ) 1.13. The maximum rate of population growth occurred in the day 33. Fecundity had two peaks: at days 35 and 37. Gross and net fecundity rate, and the average number of eggs laid per female per day were 565.87, 496.07, and 18.76 respectively. The biotic potential was 2.026 x 1018 individuals/female/year. The survivorship curve showed that mortality was high during incubation period and first larval instars, then it declined until the death of last adult. These results provide important information to develop management strategies of H. gelotopoeon in South America.

ABSTRACT: Zoonotic parasitic infections are a major global public and veterinary health problem and widespread among stray dogs. The objective of this study was to establish the prevalence of intestinal parasites in stray dogs in the urban, rural and coastal areas of Mexicali County in northwest Mexico. In 2014, from January to December, 380 stray dogs were captured. The entire small intestine, cecum and faeces samples were collected and examined by using simple zinc sulfate flotation and Lugol’s solution staining. Data were statistically analysed. Overall, about 21.5% of examined dogs were found positive for intestinal parasites. Toxocara canis was the most frequent detected parasite, with a prevalence of 7.1%, followed by Toxascaris leonina (5.5%), Cystoisospora spp. (5.0%), Taenia spp. (3.9%) and Dipylidium caninum (2.8%). Dogs were more frequently found to be infected with a single genus of intestinal parasite (18.7%) than co-infected (2.8%). Intestinal parasites were more prevalent in samples from the coastal area (25%) than in those from the rural (24.4%) and urban (20.6%) areas, however, only statistical association was found between capture area and specific intestinal parasitic infection. There were significant differences in the prevalence of taeniasis among two age groups (P<0.01). A seasonal peak of prevalence for intestinal parasitic infections was found during spring (P<0.05), corresponding with a seasonal peak of prevalence of T. canis (P<0.05). The wide range of isolated parasites indicated that people residing in this area are at risk of exposure to these potentially hazardous zoonotic pathogens.

RESUMEN: Las infecciones zoonóticas parasitarias son un problema global público y para la medicina veterinaria, siendo diseminadas por perros callejeros. El objetivo del estudio fue determinar la prevalencia de parasitosis intestinales en perros callejeros de la zona urbana, rural y costera del municipio de Mexicali, noroeste de México. En 2014, entre enero y diciembre, se capturaron 380 perros. Se colectó el intestino, ciego y heces y se examinaron utilizando flotación con sulfato de zinc y tinción con la solución de Lugol. Los datos fueron analizados estadísticamente. En general, alrededor del 21,5% de los perros examinados fueron positivos a parásitos intestinales. Toxocara canis fue el parásito más frecuentemente, con una prevalencia del 7,1%, seguido por Toxascaris leonina (5,5%), Cystoisospora spp. (5,0%), Taenia spp. (3,9%) y Dipylidium caninum (2,8%). Los perros fueron más frecuentemente encontrados infectados con un solo género de parásito intestinal (18,7%) que coinfectados (2,8%). Las parasitosis intestinales fueron más prevalentes en muestras de la costa (25%) que del área rural (24,4%) y urbana (20,6%), sin embargo solo se encontró asociación estadística entre el área de captura y las parasitosis intestinales específicas. Hubo diferencias significativas en la prevalencia de taeniasis entre los dos grupos de edad (P<0,01). El pico estacional de la prevalencia de infecciones parasitarias intestinales se encontró durante la primavera (P<0,05), correspondiendo con el pico estacional de T. canis (P<0,05). La amplia gama de parásitos aislados indicó que las personas que residen en esta zona están en riesgo de exposición a estos patógenos zoonóticos potencialmente peligrosos.

ABSTRACT This study presents registers of Helicoverpa armigera (Hübner) occurrence to assess its spatial and temporal distribution in Brazil. We used data from collections, especially from the Southern Region, systematic collections in Rio Grande do Sul, occasional collections of caterpillars and adults in different regions of Brazil, as well as literature registers. We conclude that the introduction of H. armigera in Brazil probably occurred before October 2008. We also register that in August 2012 H. armigera was already present from the extreme southern part (Rio Grande do Sul) to the extreme northern part (Amapá) of Brazil.

ABSTRACT The biotic potential and reproductive parameters of Spodoptera dolichos (Fabricius, 1794) were evaluated under controlled conditions (25 ± 1°C, 70 ± 10% RH and 14 hour photophase). The longevity, pre-, post- and oviposition periods, fecundity, and fertility of 25 couples were evaluated. The longevity of females (12.9 days) was not significantly different than that of males (12.4 days). The mean durations of the pre-, post- and oviposition periods were 3.0, 0.4 and 10.4 days, respectively. The mean fecundity was 4,086.0 eggs per female and mean fertility was 3,557.8 larvae per female. On average, a female copulated 1.4 times. The biotic potential of S. dolichos was estimated at 7.138 x 1018 individuals/female/year. The net reproductive rate (Ro) was 1,711.98 times per generation and the mean generation time (T) was 56.19 days. The intrinsic rate of increase (rm) was 0.133, with a finite rate of increase (l) of 1.142 per day. These results are compared with other species from Spodoptera and their relevance for management strategies of S. dolichos.

Este trabalho objetivou avaliar o potencial biótico e parâmetros da tabela de vida e fertilidade de Spodoptera albula (Walker, 1857) em condições controladas (25 ± 1°C, 70 ± 10% UR e fotofase de 14 horas). Avaliou-se a longevidade, períodos de pré, pós e oviposição, fecundidade e fertilidade de 13 casais. A longevidade das fêmeas (13,500 dias) foi significativamente maior que a dos machos (11,154 dias). A duração dos períodos médios de pré, pós e oviposição foram de 2,615, 1,769 e 9,385 dias, respectivamente. A fecundidade média foi de 1.417,69 ovos e a fertilidade 1.340,401 larvas por fêmea. Em média, as fêmeas copularam 1,231 vezes. Observou-se forte correlação positiva entre número de cópulas e a fecundidade (r = 0,847, p < 0,001) e, forte correlação negativa, entre o número de cópulas e a duração do período de pré-oviposição (r = -0,762, p = 0,002), e a longevidade (r = -0,788, p = 0,001). O potencial biótico de S. albula foi estimado em 8,768 x 1022 indivíduos/fêmea/ano. A taxa líquida de reprodução (Ro) foi de 353.904 vezes por geração e o tempo médio de uma geração (T) foi de 37,187 dias. A taxa intrínseca de aumento (rm) foi de 1,105, com uma razão finita de aumento (λ) de 3,019.

This study aimed to evaluate the biotic potential, life table parameters and fertility of Spodoptera albula (Walker, 1857) under controlled conditions (25 ± 1°C, 70 ± 10% RH and 14 hour photo phase). The longevity, pre, post and oviposition periods, fecundity and fertility of 13 couples were evaluated. The longevity of females (13.500 days) was significantly higher than those of males (11.154 days). The mean durations of the pre, post and oviposition periods were 2.615, 1.769 and 9.385 days, respectively. The mean fecundity was 1.417.69 eggs and mean fertility was 1.340.401 larvae, per female. On average, females copulated 1, 231 times. A strong positive correlation was observed between the number of copulations and fecundity (r = 0.847, p <0.001), as well as a strong negative correlation between the number of copulations and the duration of the pre-oviposition period (r = -0.762, p = 0.002), and longevity (r = -0.788, p = 0.001). The biotic potential of S. albula was estimated at 8.768 x 1022 individuals / female / year. The net reproductive rate (Ro) was 353,904 times per generation and the mean generation time (T) was 37.187 days. The intrinsic rate of increase (rm) was 1,105, with a finite rate of increase (λ) of 3,019.

Este estudo objetivou detalhar parâmetros biológicos dos estágios imaturos de Spodoptera albula (Walker 1857) em condições controladas (25 ± 1°C, 70 ± 10% UR e fotofase de 14 horas) e reunir informações sobre as plantas hospedeiras de suas larvas. Para tanto foram empregadas e validadas novas metodologias de criação e dieta artificial. A viabilidade das fases de ovo, larva, pré-pupa e pupa foi de 94,54; 97,33; 93,84 e 92,34%, respectivamente. A duração média das fases de ovo, larva, pré-pupa e pupa foi de 4,14; 16,37; 1,69; e 9,34 dias, respectivamente. Na fase de larva observou-se que 80,85% das fêmeas e 93,99% dos machos passaram por seis instares e os demais por sete, com protandria larval significativa. As larvas que passaram por seis e sete instares apresentaram razão média de crescimento de 1,58 e 1,48, respectivamente. Foram relacionadas 55 plantas pertencentes a 29 famílias botânicas. As pupas femininas foram significativamente maiores, observando-se protoginia. Tanto a metodologia de criação quanto a dieta larval mostraram-se adequadas, pois permitiram sobrevivência total de praticamente 80% e um detalhamento muito maior das observações relacionadas ao ciclo biológico, especialmente do estágio larval.

This study aimed to detail the temporal and morphological parameters of the immature stages of Spodoptera albula (Walker 1857) under controlled conditions (25 ± 1°C, 70 ± 10% RH and 14 hour photophase) and to gather information about their larval host plants. For this purpose, a new rearing method and artificial diet was employed and validated. The viability of the egg, larval, pupal and pre-pupal stages was 94.54, 97.33, 93.84 and 92.34%, respectively. The average duration of the egg, larval, pupal and pre-pupal stages was 4.14, 16.37, 1.69, and 9.34 days, respectively. During the larval stage, 80.85% of females and 93.99% of males passed through six and remaining through seven instars, with significant larval protandry. The larvae that developed through six and seven instars exhibited a mean growth rate of 1.58 and 1.48, respectively. Fifty five host plant species belonging to 29 families are listed. The female pupae were significantly larger, exhibiting protogyny. Both the rearing methods as well as the larval diet proved adequate, providing more detailled observations of the biological cycle, especially the larval stage, and resulting in an overall survival of almost 80%.

Chlosyne lacinia saundersii é uma das mais importantes pragas da cultura do girassol e o principal alvo das aplicações de inseticidas. As larvas foram coletadas em Londrina (PR), Santa Maria (RS), Dourados (MS), Ribeirão Preto (SP), Brasília (DF), Barreiras (BA), Uberaba (MG) e Vilhena (RO). O DNA genômico foi extraído e amplificado com dez primers, que produziram 101 locos. O tamanho das amplificações de RAPD variou de 180 a 2564 pb. O polimorfismo entre as populações variou de 31% a 67%, com maior polimorfismo 57% e 67%, detectado em populações de Uberaba e Vilhena, respectivamente. As populações com maior similaridade determinada com o coeficiente de Dice foram de Ribeirão Preto e Barreiras, enquanto os insetos coletados em Londrina apresentaram maior similaridade entre eles. O fluxo gênico de C. lacinia saundersii de 1,1 foi menor que o observado para a Anticarsia gemmatalis Hübner Noctuidae, sugerindo que as populações de C. lacinia saundersii estão mais isoladas do que estes noctuideos. Através da análise de variância molecular (AMOVA), RAPD a variação foi de 33,64% entre as populações geográficas e 66,36% dentro das populações. Estes resultados sugere que as populações de C. lacinia saundersii são geneticamente estruturadas.

Chlosyne lacinia saundersii is one of the most important pests of sunflower and it is the main target of insecticides applications. Larvae were collected in Londrina (PR), Santa Maria (RS), Dourados (MS), Ribeirão Preto (SP), Brasília (DF), Barreiras (BA), Uberaba (MG) and Vilhena (RO). Genomic DNA was extracted and amplified with ten-mer primers, which produced 101 loci. The size of the RAPD amplicons ranged from 180 to 2564 bp. Polymorphism among populations ranged from 31% to 67%, with the highest polymorphisms of 57% and 67% being detected in Uberaba and Vilhena populations, respectively. Populations with the highest similarity determined with Dice coefficient were from Ribeirão Preto and Barreiras, while insects from Londrina showed the highest similarity among them. Gene flow of C. lacinia saundersii 1.1 was lower than those previously observed for the noctuid Anticarsia gemmatalis Hübner, suggesting that C. lacinia saundersii populations are more isolated than the ones of this noctuid. Through the Analysis of Molecular Variance (AMOVA), RAPD variance was 33.64% among geographical populations and 66.36% within populations. These results suggest that populations of C. lacinia saundersii are genetically structured.

Chemical insecticides are used for Spodoptera frugiperda control, a key pest affecting corn crops in North Western Argentina. These insecticides, however, frequently show low effectiveness. The baculoviruses are a biological alternative to control the fall armyworm. The objective of this research was to assess Nucleopolyhedrovirus native and foreign strains as regards their effectiveness in controlling S. frugiperda. The results showed that S. frugiperda larvae death rate rose with increasing viral concentrations, while viral susceptibility of larvae decreased with insect age. LC50 (lethal concentration for 50% of the tested sample) of 7.6 x 10(4) and 4.5 x 10(5) polyhedra/ml for three and five day-old larvae, respectively, were determined for the nuclear polyhedrosis virus (NPV) isolated in Leales (Tucumán, Argentina). Similar control levels were determined for the NPV isolated in Oliveros (Santa Fe, Argentina), with lethal viral concentrations (LC50) of 8.6 x 10(4) and 4.0 x 10(5) polyhedra/ml, respectively. The Brazilian isolate was characterized by LC50 levels of 5.9 x 10(5) and 1.5 x 10(6) polyhedral/ml for three-day-old and five-day-old larvae, respectively. The local isolate (VPNSf -Tucumán) showed the most lethal effect on the native population of young S. frugiperda (three to five-day-old) larvae, with an average lifespan of six days at LC50 levels, while the Oliveros and Brazil isolates showed an average lifespan of seven and nine days, respectively. The VPNSf - Leales isolate was therefore selected as the object of study for this research. Moreover, being a native isolate, it was considered the best alternative from the environmental impact standpoint.

Para el control de Spodoptera frugiperda (Smith), plaga clave del maíz en el noroeste argentino (NOA), se utilizan insecticidas químicos que muestran en muchas ocasiones, una baja efectividad. Los baculovirus constituyen una alternativa biológica para el manejo del gusano cogollero. El propósito de este trabajo fue evaluar la susceptibilidad de estadios larvales de S. frugiperda a distintas concentraciones de tres aislamientos del Nucleopolyhedrovirus de diferentes procedencias. Los resultados obtenidos permitieron constatar que la mortalidad de las orugas de S. frugiperda aumentó con el incremento de la concentración viral y que la susceptibilidad larval al virus decreció con el aumento de la edad del insecto. Se determinó una concentración letal media (CL50) de 7,6 x 10(4) y 4,5 x 10(5) poliedros/ml en larvas de tres y cinco días respectivamente, para el VPN aislamiento Leales (Tucumán, Argentina). Con niveles similares se ubicó el aislamiento Oliveros (Santa Fe, Argentina), cuya CL50 fue de 8,6 x 10(4) poliedros/ml y 4 x 10(5) poliedros/ml, respectivamente. Por último, el aislamiento oriundo de Brasil presentó CL50 igual a 5,9 x 105 poliedros/ml para larvas de tres días, y 1,5 x 106 poliedros/ml para orugas de cinco días. El aislamiento local demostró la mayor virulencia en la población nativa de larvas de S. frugiperda, registrando para larvas jóvenes (tres y cinco días de edad) y a los valores de concentración letal media, un tiempo medio de mortalidad de seis días, resultando siete días para el aislamiento Oliveros y nueve días para el aislamiento Brasil. Considerando los resultados obtenidos, el VPNSf aislamiento Leales tuvo el mejor desempeño y sería conveniente continuar los estudios destinados a desarrollar un bioinsecticida para uso local, ya que evidencia una adecuada virulencia. Además, al ser un aislamiento nativo, su empleo sería el más apropiado en términos de impacto ambiental.

O complexo de percevejos da soja possui um grande potencial de dano, seu controle é difícil ao final da safra por suas elevadas densidades populacionais. Trabalhos relacionados com organismos entomopatogênicos em percevejos são interessantes devido a suas possibilidades como agentes de controle e porque eles podem ser agentes causais de doenças em criação massal. A prevalência de tripanossomatídeos foi determinada nas espécies mais importantes da cultura da soja, no Brasil, Nezara viridula (L.), Euschistus heros (Fabricius) e Piezodorus guildinii (Westwood). Os insetos foram coletados na soja e hospedeiros alternativos durante a entressafra. Gotas de hemolinfa de cada adulto foram montadas em lâminas e observadas ao microscópio; o número de percevejos com e sem flagelados foi registrado. Os flagelados encontrados nas populações de P. guildinii e E. heros foram menores que os observados em N. viridula. A maior prevalência dos tripanossomatídeos foi observada nos espécimes de N. viridula coletados na soja alcançando 30% de infecção em janeiro, 2001, e 44% prevalência em fevereiro de 2003. Em P. guildinii as máximas prevalências foram observadas em janeiro e fevereiro de 2003 (16%) e em 27 de julho de 2003 com 20% dos espécimes infectados. Os flagelados na hemolinfa de E. heros foram menos freqüentes (máxima prevalência de 8,7%), sugerindo que esta espécie é menos suscetível que N. viridula e P. guildinii. Embora os níveis de prevalência sejam mais elevados que os observados para fungos entomopatogênicos, os tripanossomatídeos não parecem ser eficientes reguladores das populações de percevejos de percevejos em curto prazo.

The stink bug complex in soybeans has a great potential to cause damage, their control has been difficult due to high population densities at the end of the season. Studies related to entomopathogenic organisms in stink bugs are interesting for their possibilities to be used as biological control agents and because they could be an etiological agent in mass rearing. We determined the prevalence of trypanosomatids in the most important species of the stink bug complex in soybean, from Brazil, Nezara viridula (L.), Euschistus heros (Fabricius) and Piezodorus guildinii (Westwood). Insects were collected in soybean and on alternate hosts during the intercrop season. Hemolymph drops from each adult were mounted on slides and observed under microscope; stink bug numbers with and without flagellates were recorded. The flagellates found in P. guildinii or E. heros populations were smaller than that found in N. viridula. The higher prevalence of the trypanosomatids was observed on soybean reaching a peak of 30% of the sampled N. viridula specimens in January, 2001, and 44% prevalence in February, 2003. The maximum prevalences (16%) in P. guildinii were observed in January and February, 2003 and on July 27, 2003 with 20% of the specimens infected. Flagellates in the hemolymph of E. heros were less frequent (maximum prevalence of 8.7%), suggesting that this species is less susceptible than N. viridula and P. guildinii. Trypanosomatid prevalence was higher than that observed for entomopathogenic fungi, however they seem to be inefficient control agents in short term condition.

The velvetbean caterpillar (VBC), Anticarsia gemmatalis Hübner, 1818 (Insecta: Lepidoptera: Noctuidae), is one of the most important New World soybean agro-ecosystems pests, occurring from 40° N in the USA to 39° S in Argentina. Information on the migration patterns of the VBC moth may be important for managing the resistance of VBC populations to insecticides or plants carrying the Bacillus thuringiensis insecticide genes, especially since sedentary populations have a higher potential to became resistant than migratory populations. We studied intraspecific variations of geographically distinct VBC populations in order to determine the genetic distance between them and to assess the variability of VBC populations from near the city of Londrina (Paraná (PR) state, Brazil). Samples of the VBC were obtained from sites near the following towns or cities: Marianna and Quincy (Florida, USA); La Virginia (Tucumán province, Argentina); Londrina (PR), Passo Fundo (Rio Grande do Sul, Brazil) and Planaltina (Goiás, Brazil). The VBC samples were used to construct a genetic similarity matrix based on random amplified polymorphic DNA (RAPD) allele frequencies, the cotton leafworm, Alabama argillacea, Hübner 1823 (Insecta: Lepidoptera: Noctuidae), being used as an outgroup. Interestingly, despite the great distance (about 6,500 km) between Planaltina and Quincy some of the specimens from the Quincy population clustered in a group genetically close to the Planaltina populations. Larvae collected on peanuts in Marianna and on soybean in Quincy, 70 km apart, appeared genetically similar. The population from Planaltina was the most heterogeneous (polymorphism = 85.6%; heterozygosity = 0.1505). The Argentinean VBC population was entirely different from the Brazilian populations. The genetic similarities found between individuals from geographically distant populations and effective migration rate values (2.0566 > Nm < 15.2618) indicate that migration occurs.

O fungo Nomuraea rileyi (Farlow) Samson é um dos inimigos naturais mais importantes de lagartas da soja, principalmente em condições de tempo úmido. Surtos de oídio têm demandado a aplicação de fungicidas na soja, especialmente nas etapas iniciais do ciclo agrícola, época na qual a interferência sobre N. rileyi pode favorecer a ocorrência de lagarta por redução do inóculo desse fungo. Ensaios de laboratório mostraram que benomil, difenoconazole, enxofre e carbendazim reduziram a germinação de N. rileyi sendo o último menos deletério. Para avaliar o impacto dos fungicidas utilizados no controle do oídio sobre N. rileyi, foram realizadas aplicações com difenoconazole (75 g i.a./ha) ou benomil (262,5 g i.a./ha) em parcelas de soja. No ensaio realizado em 1997/1998 foi realizada apenas uma aplicação de fungicida, estando as plantas no estágio R1-R2. No ensaio realizado em 1998/99 realizaram-se duas aplicações, espaçadas de 19 dias, quando as plantas estavam nos estágios V5 e V7, respectivamente. O número de lagartas foi significativamente maior nas parcelas tratadas com os fungicidas que nas parcelas testemunhas. Em 1997/98, a parcela tratada com benomil apresentou população mais elevada da lagarta-da-soja que nas parcelas testemunhas ou na tratada com difenoconazole. Em 1998/99, a população da lagarta-da-soja foi maior entre o sétimo e décimo segundo dia após a primeira aplicação, e continuou alta até o décimo nono dia após a segunda aplicação. Os fungicidas causaram um atraso de 2 a 14 dias na iniciação da epizootia de N. rileyi.

The fungus Nomuraea rileyi (Farlow) Samson is one of the most important natural enemies of soybean caterpillars, mainly under humid weather conditions. Outbreaks of the fungus Microsphaera diffusa Cooke & Peck have demanded fungicide applications on soybeans, which could result in outbreaks of noctuid populations by reduction of the natural inocula of N. rileyi. The recommended fungicides have shown to be detrimental to beneficial fungi, reducing infection, delaying epizootics, and resulting in increased host population densities. In laboratory assays, benomyl, difenoconazole, sulphur and carbendazim affected conidial germination of N. rileyi, being the latter less deleterious. To assess the impact of fungicides used to control M. diffusa, on N. rileyi, two tests were carried on, spraying difenoconazole (75 g a.i./ha) and benomyl (262.5 g a.i./ha) on soybean plots. In the 1997/98 trial, fungicide was sprayed once on soybean plants at R1-R2 developmental stages. In the 1998/99 test, two applications were made, when plants were at V5 and V7 developmental stages, respectively. The number of VBC larvae was significantly higher in the fungicide treated plots than in the control plots. In the 1997/98 test, benomyl treated plots resulted in higher populations of VBC than in the control or in the difenoconazole plots. In the 1998/99 test, VBC population was higher from 7 to 12 days after the first application, and remained high until 19 days after the second application. In general, fungicide treatments delayed the begining of N. rileyi epizootics from 2 to 14 days.

A ocorrência de fungos entomopatogênicos Metarhizium, Beauveria e Paecilomyces foi estudada em condições de semeadura direta e convencional da soja. Foi determinada a densidade de unidades formadoras de colônia por g de solo e por cm² de folíolos de soja. Verificou-se que no solo sob semeadura direta ocorreu maior incidência dos entomopatógenos, mas sobre os folíolos essa diferença não ocorreu, proporcionando as mesmas possibilidades de infecção nos insetos da parte aérea suscetíveis que ocorrem nas duas condições de cultivo.

The occurrence of the entomopathogenic fungi Metarhizium, Beauveria and Paecilomyces in soybean under till and no-till cultivation systems was studied. The number of colony forming units per g of soil and per cm² of leaf area was determined. Soil under no-till system showed a higher incidence of entomopathogenic fungi, but no difference in fungal density was observed on leaves. Thus the probability of infection for susceptible leaf inhabiting insects should be similar in both systems.

A fase reprodutiva dos fungos entomopatogênicos é dependente da quantidade de água em torno do local onde se encontram. Neste trabalho realizaram-se ensaios para quantificar a formação de conídios de Beauveria bassiana (Bals.) Vuill. sobre cadáveres de Diatraea saccharalis F. (Lepidoptera: Pyralidae), Nezara viridula (L.) e Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae) mantidos em diferentes níveis de umidade relativa (UR) (75%, 80%, 85%, 90% e 100%) associadas com temperaturas de 22°C, 26°C, 30°C e 34°C durante cinco dias. Os isolados formaram conídios entre 75% e 100% de UR. A conidiogênese foi incipiente a 75% de UR sobre larvas de D. saccharalis, mas não se manifestou sobre os percevejos N. viridula e P. guildinii. Foram determinadas as equações que explicam a conidiogênese dos isolados ARSEF 933 e ARSEF 2515 em um período de dez dias, em condições ideais de umidade. O número de conídios formados foi função da UR, temperatura, isolado de fungo, espécie hospedeira, fase do hospedeiro e tempo.

Assays were conducted to assess the number of Beauveria bassiana (Bals.) Vuill. conidia on Diatraea saccharalis F. (Lepidoptera: Pyralidae), Nezara viridula (L.) and Piezodorus guildinii (Westwood) (Hemiptera: Pentatomidae) corpses maintained at different levels of relative humidity (RH) (75%, 80%, 85%, 90% and 100%) and temperatures (22°C, 26°C, 30°C and 34°C) during five days. The isolates produced conidia when exposed to RH from 75% to 100%. Conidiogenesis was incipient at 75% RH on D. saccharalis larvae, but did not occur on N. viridula and P. guildinii. In ideal conditions of RH and during 10 days, mathematical equations were developed to estimate the number of conidia produced by isolates ARSEF 933 and ARSEF 2515. Conidia number were shown to be dependant on RH, temperature, fungal isolate, host species, host stage, and time

Avaliou-se em laboratório o efeito de diferentes concentrações de ácido bórico sobre a atividade do vírus de poliedrose nuclear (VPN) da lagarta-da-soja, Anticarsia gemmatalis Hüb., através da sua incorporação na dieta do inseto. O ácido bórico foi testado nas concentrações de 0,020,0,030,0,045,0,067 e 0,101 gramas/100 ml de dieta. A concentração letal média (CL50) do VPN isoladamente, calculada no sétimo dia após a infecção, foi de 1,52 x 10(5) corpos poliédricos de inclusão (CPI)/ml de dieta, enquanto que, para a suspensão adicionada de 0,045 g de ácido bórico, foi de 7,95 x 10² CPI/ml de dieta. Em datas subsequentes de avaliação (9, 11 e 14 dias da infecção) os valores da CL da mistura foram cerca de quatro vezes inferiores aos obtidos com o VPN isoladamente. O tempo letal médio (TL50) do VPN isoladamente, na dose de 250 CPI/ml de dieta, foi de 13,6 dias, enquanto que para doses crescentes do ácido bórico, em mistura com o VPN, o TL50 variou de 13,7 dias (0,02g de ácido bórico/100 ml de dieta) a 7,4 dias (O,101 g de ácido bórico/100 ml de dieta). Portanto, a adição de ácido bórico ao VPN aumentou a virulência do patógeno para A gemmatalis e diminuiu seu tempo de atuação sobre o inseto.

Boric acid concentrations (0.02,0.03,0.045,0.067 and 0.101 g/100 ml of diet) were evaluated in combination with the Anticarsia gemmatalis Hüb. nuclear polyhedrosis virus (AgNPV) for enhanced virali activity against the insect. Seven days after inoculation, the median lethal concentration (LC50) was 1.52 x 10(5) for the AgNPV alone and 7.95 x 10² for the NPV mixed with 0.045g of boric acid/100 ml of diet. At subsequent evaluation dates (9,11 and 14 days after inoculation) LC50's for NPV+boric acid were ca. 4x lower than those observed for the NPV alone. The median lethal time (LT50) was 13.6 days when the NPV was used alone, while, when in mixture with increasing concentrations of boric acid, LT50 values ranged from 13.7 days (boric acid at 0.02g/100 ml of diet) to 7.4 days (boric acid at 0.101 g/ml of diet). Therefore, boric acid added to the AgNPV significantly increased A. gemmatalis larval mortality and shortened mortality time by the pathogen.