Perceptions, maltreatment and religion as predictors of the psycho-emotional impact on nurses during the COVID-19 pandemic.

OBJECTIVES: to analyze the relationship between perceptions, abuse and religion with the psycho-emotional impact on nurses during the COVID-19 pandemic. METHODS: descriptive-analytical cross-sectional study. It took place between 2020 and 2021 and a total of 319 clinical nurses in Peru were interviewed using the DASS-21. Associations were assessed using Spearman's Rho and multiple regression. RESULTS: 18.5% had some degree of stress; 50.2%, anxiety and 29.1%, depression. Experience of abuse, self-perception of mental health and religion were predictors of stress, anxiety and depression. The length of work experience predicts stress and anxiety. In addition, self-perception of information and gender were predictors of depression. CONCLUSIONS: peruvian nurses have high levels of stress, anxiety and depression, and this psycho-emotional impact was associated with perceptions, experiences of abuse and religion.

Perceptions, maltreatment and religion as predictors of the psycho-emotional impact on nurses during the COVID-19 pandemic / Percepções, maltrato e religião como preditores do impacto psicoemocional em enfermeiros durante a pandemia de COVID-19 / Percepciones, maltrato y religión como predictores del impacto psicoemocional en enfermeros durante la pandemia COVID-19

ABSTRACT Objectives: to analyze the relationship between perceptions, abuse and religion with the psycho-emotional impact on nurses during the COVID-19 pandemic. Methods: descriptive-analytical cross-sectional study. It took place between 2020 and 2021 and a total of 319 clinical nurses in Peru were interviewed using the DASS-21. Associations were assessed using Spearman's Rho and multiple regression. Results: 18.5% had some degree of stress; 50.2%, anxiety and 29.1%, depression. Experience of abuse, self-perception of mental health and religion were predictors of stress, anxiety and depression. The length of work experience predicts stress and anxiety. In addition, self-perception of information and gender were predictors of depression. Conclusions: peruvian nurses have high levels of stress, anxiety and depression, and this psycho-emotional impact was associated with perceptions, experiences of abuse and religion.

RESUMO Objetivos: analisar a relação entre percepções, abuso e religião com o impacto psicoemocional nos enfermeiros durante a pandemia de COVID-19. Métodos: estudo transversal descritivo-analítico. Realizado entre 2020 e 2021; foram entrevistados 319 enfermeiros assistenciais no Peru por meio do DASS-21; as associações foram avaliadas usando Rho de Spearman e regressão múltipla. Resultados: 18,5% apresentaram algum grau de estresse; 50,2%, ansiedade e 29,1%, depressão. Experiência de abuso, autopercepção de saúde mental e religião foram preditores de estresse, ansiedade e depressão. O tempo de experiência de trabalho prediz estresse e ansiedade. Além disso, a autopercepção das informações e o gênero foram preditores de depressão. Conclusões: os enfermeiros peruanos apresentam altos níveis de estresse, ansiedade e depressão; e esse impacto psicoemocional foi associado a percepções, experiências de abuso e religião.

RESUMEN Objetivos: analizar la relación entre percepciones, maltrato y religión con el impacto psicoemocional en enfermeros durante la pandemia por covid-19. Métodos: estudio transversal descriptivo-analítico. Fue realizado entre los años 2020 y 2021; se encuestó a 319 enfermeros asistenciales de Perú mediante DASS-21; se evaluaron asociaciones mediante Rho de Spearman y regresión múltiple. Resultados: el 18,5 % presentó algún grado de estrés; el 50,2 %, ansiedad y el 29,1 %, depresión. La experiencia de maltrato, la autopercepción de la salud mental y la religión fueron predictores de estrés, ansiedad y depresión. El tiempo de experiencia laboral predice el estrés y ansiedad. Además, la autopercepción de la información y el género fueron predictores de la depresión. Conclusiones: los enfermeros peruanos presentaron altos niveles de estrés, ansiedad y depresión; y este impacto psicoemocional estuvo asociado a las percepciones, experiencias de maltrato y la religión.

Worry and fear as predictors of fatalism by COVID-19 in the daily work of nurses. / Preocupação e medo como preditores de fatalismo por COVID-19 no cotidiano de trabalho dos enfermeiros.

OBJECTIVE: to analyze the relationship between the concern and fear of COVID-19 with fatalism in the daily work of nurses. METHOD: analytical cross-sectional study carried out with a total of 449 nurses. Data collection was performed using instruments validated in Peru. In the analysis, the Shapiro-Wilk test and the Spearman correlation coefficient were used, and two multiple regression models were estimated, with variable selection in stages. RESULTS: nurses had a moderate level of fatalism and a low level of fear and concern about COVID-19. The first statistical model, which included sociodemographic variables, explains only 3% of the fatalism variance. However, a second model that includes fear and perception explains 33% of it. CONCLUSION: Worry, fear and having been diagnosed with COVID-19 were predictors of fatalism. It is suggested the implementation of psycho-emotional interventions in daily work - aimed at Nursing professionals who present high levels of fear or concern - to reduce fatalism and prevent fatal consequences of the pandemic and promote health.

Preocupação e medo como preditores de fatalismo por COVID-19 no cotidiano de trabalho dos enfermeiros / Worry and fear as predictors of fatalism by COVID-19 in the daily work of nurses / Preocupación y miedo como predictores de fatalismo por COVID-19 en lo cotidiano laboral de enfermeros

Resumo Objetivo: analisar a relação entre a preocupação e o medo da COVID-19 com o fatalismo no cotidiano de trabalho dos enfermeiros. Método: estudo transversal analítico, realizado com 449 enfermeiros. A coleta de dados foi realizada por meio de instrumentos validados no Peru. Na análise, foram utilizados o teste de Shapiro-Wilk e o coeficiente de correlação de Spearman, sendo estimados dois modelos de regressão múltipla, com seleção de variáveis por etapas. Resultados: os enfermeiros apresentaram nível moderado de fatalismo e baixo nível de medo e preocupação com a COVID-19. O primeiro modelo estatístico, que incluiu variáveis sociodemográficas, explica apenas 3% da variância de fatalismo. No entanto, um segundo modelo que inclui medo e percepção explica 33%. Conclusão: a preocupação, o medo e ter sido diagnosticado com COVID-19 foram fatores preditores de fatalismo. Sugere-se a implementação de intervenções psicoemocionais no cotidiano de trabalho, voltadas para profissionais de Enfermagem que apresentem altos níveis de medo ou preocupação, para reduzir o fatalismo e, assim, prevenir consequências fatais da pandemia e promover a saúde.

Abstract Objective: to analyze the relationship between the concern and fear of COVID-19 with fatalism in the daily work of nurses. Method: analytical cross-sectional study carried out with a total of 449 nurses. Data collection was performed using instruments validated in Peru. In the analysis, the Shapiro-Wilk test and the Spearman correlation coefficient were used, and two multiple regression models were estimated, with variable selection in stages. Results: nurses had a moderate level of fatalism and a low level of fear and concern about COVID-19. The first statistical model, which included sociodemographic variables, explains only 3% of the fatalism variance. However, a second model that includes fear and perception explains 33% of it. Conclusion: Worry, fear and having been diagnosed with COVID-19 were predictors of fatalism. It is suggested the implementation of psycho-emotional interventions in daily work - aimed at Nursing professionals who present high levels of fear or concern - to reduce fatalism and prevent fatal consequences of the pandemic and promote health.

Resumen Objetivo: analizar la relación entre la preocupación y el miedo al COVID-19 con el fatalismo, en lo cotidiano laboral de los enfermeros. Método: estudio transversal tipo analítico, realizado en 449 enfermeros. La recolección de datos se realizó mediante instrumentos validados en Perú. En el análisis se utilizó la prueba de Shapiro-Wilk, el coeficiente de correlación de Spearman y se estimaron dos modelos de regresión múltiple, con selección de variables por pasos. Resultados: los enfermeros presentaron un nivel moderado de fatalismo y un nivel bajo de miedo y preocupación por la COVID-19. El primer modelo estadístico que incluyó las variables sociodemográficas apenas explica un 3% de la varianza de fatalismo; sin embargo, un segundo modelo que incluye el miedo y la percepción explica el 33%. Conclusión: la preocupación, el miedo y el haber sido diagnosticado con COVID-19 fueron factores predictores de fatalismo. Se sugiere implementar intervenciones psicoemocionales en el cotidiano laboral - focalizadas en profesionales de Enfermería que presenten altos niveles de miedo o preocupación - para reducir el fatalismo y de esta manera prevenir consecuencias fatales de la pandemia y promover la salud.

Iflavirus Covert Infection Increases Susceptibility to Nucleopolyhedrovirus Disease in Spodoptera exigua.

Naturally occurring covert infections in lepidopteran populations can involve multiple viruses with potentially different transmission strategies. In this study, we characterized covert infection by two RNA viruses, Spodoptera exigua iflavirus 1 (SeIV-1) and Spodoptera exigua iflavirus 2 (SeIV-2) (family Iflaviridae) that naturally infect populations of Spodoptera exigua, and examined their influence on susceptibility to patent disease by the nucleopolyhedrovirus Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) (family Baculoviridae). The abundance of SeIV-1 genomes increased up to ten-thousand-fold across insect developmental stages after surface contamination of host eggs with a mixture of SeIV-1 and SeIV-2 particles, whereas the abundance of SeIV-2 remained constant across all developmental stages. Low levels of SeIV-2 infection were detected in all groups of insects, including those that hatched from surface-decontaminated egg masses. SeIV-1 infection resulted in reduced larval weight gain, and an unbalanced sex ratio, whereas larval developmental time, pupal weight, and adult emergence and fecundity were not significantly affected in infected adults. The inoculation of S. exigua egg masses with iflavirus, followed by a subsequent infection with SeMNPV, resulted in an additive effect on larval mortality. The 50% lethal concentration (LC50) of SeMNPV was reduced nearly 4-fold and the mean time to death was faster by 12 h in iflavirus-treated insects. These results suggest that inapparent iflavirus infections may be able to modulate the host response to a new pathogen, a finding that has particular relevance to the use of SeMNPV as the basis for biological pest control products.

Covert Infection of Insects by Baculoviruses.

Baculoviruses (Baculoviridae) are occluded DNA viruses that are lethal pathogens of the larval stages of some lepidopterans, mosquitoes, and sawflies (phytophagous Hymenoptera). These viruses have been developed as biological insecticides for control of insect pests and as expression vectors in biotechnological applications. Natural and laboratory populations frequently harbor covert infections by baculoviruses, often at a prevalence exceeding 50%. Covert infection can comprise either non-productive latency or sublethal infection involving low level production of virus progeny. Latency in cell culture systems involves the expression of a small subset of viral genes. In contrast, covert infection in lepidopterans is associated with differential infection of cell types, modulation of virus gene expression and avoidance of immune system clearance. The molecular basis for covert infection may reside in the regulation of host-virus interactions through the action of microRNAs (miRNA). Initial findings suggest that insect nudiviruses and vertebrate herpesviruses may provide useful analogous models for exploring the mechanisms of covert infection by baculoviruses. These pathogens adopt mixed-mode transmission strategies that depend on the relative fitness gains that accrue through vertical and horizontal transmission. This facilitates virus persistence when opportunities for horizontal transmission are limited and ensures virus dispersal in migratory host species. However, when host survival is threatened by environmental or physiological stressors, latent or persistent infections can be activated to produce lethal disease, followed by horizontal transmission. Covert infection has also been implicated in population level effects on host-pathogen dynamics due to the reduced reproductive capacity of infected females. We conclude that covert infections provide many opportunities to examine the complexity of insect-virus pathosystems at the organismal level and to explore the evolutionary and ecological relationships of these pathogens with major crop and forest pests.

Co-infection with iflaviruses influences the insecticidal properties of Spodoptera exigua multiple nucleopolyhedrovirus occlusion bodies: Implications for the production and biosecurity of baculovirus insecticides.

Biological insecticides based on Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) can efficiently control S. exigua larvae on field and greenhouse crops in many parts of the world. Spanish wild populations and laboratory colonies of S. exigua are infected by two iflaviruses (SeIV-1 and SeIV-2). Here we evaluated the effect of iflavirus co-infection on the insecticidal characteristics of SeMNPV occlusion bodies (OBs). Overall, iflavirus co-inoculation consistently reduced median lethal concentrations (LC50) for SeMNPV OBs compared to larvae infected with SeMNPV alone. However, the speed of kill of SeMNPV was similar in the presence or absence of the iflaviruses. A reduction of the weight gain (27%) associated with iflavirus infection resulted in a 30% reduction in total OB production per larva. Adult survivors of SeMNPV OB inoculation were examined for covert infection. SeMNPV DNA was found to be present at a high prevalence in all SeIV-1 and SeIV-2 co-infection treatments. Interestingly, co-inoculation of SeMNPV with SeIV-2 alone or in mixtures with SeIV-1 resulted in a significant increase in the SeMNPV load of sublethally infected adults, suggesting a role for SeIV-2 in vertical transmission or reactivation of sublethal SeMNPV infections. In conclusion, iflaviruses are not desirable in insect colonies used for large scale baculovirus production, as they may result in diminished larval growth, reduced OB production and, depending on their host-range, potential risks to non-target Lepidoptera.

Iflavirus increases its infectivity and physical stability in association with baculovirus.

Virus transmission and the prevalence of infection depend on multiple factors, including the interaction with other viral pathogens infecting the same host. In this study, active replication of an iflavirus, Spodoptera exigua iflavirus 1 (order Picornavirales) was observed in the offspring of insects that survived following inoculation with a pathogenic baculovirus, Spodoptera exigua multiple nucleopolyhedrovirus. Tracking the origin of the iflavirus suggested the association of this virus with the occlusion bodies of the baculovirus. Here we investigated the effect of this association on the stability and infectivity of both viruses. A reduction in baculovirus pathogenicity, without affecting its infectivity and productivity, was observed when associated with the iflavirus. In contrast, viral association increased the infectivity of the iflavirus and its resistance to ultraviolet radiation and high temperature, two of the main factors affecting virus stability in the field. In addition, electron microscopy analysis revealed the presence of particles resembling iflavirus virions inside the occlusion bodies of the baculovirus, suggesting the possible co-occlusion of both viruses. Results reported here are indicative of facultative phoresis of a virus and suggest that virus-virus interactions may be more common than currently recognized, and may be influential in the ecology of baculovirus and host populations and in consequence in the use of baculoviruses as biological insecticides.

Baculovirus-Induced Climbing Behavior Favors Intraspecific Necrophagy and Efficient Disease Transmission in Spodoptera exigua.

Shortly prior to death, many species of Lepidoptera infected with nucleopolyhedrovirus climb upwards on the host plant. This results in improved dissemination of viral occlusion bodies over plant foliage and an increased probability of transmission to healthy conspecific larvae. Following applications of Spodoptera exigua multiple nucleopolyhedrovirus for control of Spodoptera exigua on greenhouse-grown sweet pepper crops, necrophagy was observed by healthy S. exigua larvae that fed on virus-killed conspecifics. We examined whether this risky behavior was induced by olfactory or phagostimulant compounds associated with infected cadavers. Laboratory choice tests and olfactometer studies, involving infected and non-infected cadavers placed on spinach leaf discs, revealed no evidence for greater attraction of healthy larvae to virus-killed over non-infected cadavers. Physical contact or feeding on infected cadavers resulted in a very high incidence of transmission (82-93% lethal disease). Observations on the behavior of S. exigua larvae on pepper plants revealed that infected insects died on the uppermost 10% of foliage and closer to the plant stem than healthy conspecifics of the same stage, which we considered clear evidence of baculovirus-induced climbing behavior. Healthy larvae that subsequently foraged on the plant were more frequently observed closer to the infected than the non-infected cadaver. Healthy larvae also encountered and fed on infected cadavers significantly more frequently and more rapidly than larvae that fed on non-infected cadavers. Intraspecific necrophagy on infected cadavers invariably resulted in virus transmission and death of the necrophagous insect. We conclude that, in addition to improving the dissemination of virus particles over plant foliage, baculovirus-induced climbing behavior increases the incidence of intraspecific necrophagy in S. exigua, which is the most efficient mechanism of transmission of this lethal pathogen.

Natural populations of Spodoptera exigua are infected by multiple viruses that are transmitted to their offspring.

Sublethal infections by baculoviruses (Baculoviridae) are believed to be common in Lepidoptera, including Spodoptera exigua. In addition, novel RNA viruses of the family Iflaviridae have been recently identified in a laboratory population of S. exigua (S. exigua iflavirus-1: SeIV-1; S. exigua iflavirus-2: SeIV-2) that showed no overt signs of disease. We determined the prevalence of these viruses in wild populations and the prevalence of co-infection by the different viruses in shared hosts. Infection by S. exigua multiple nucleopolyhedrovirus (SeMNPV) and iflaviruses in S. exigua adults (N=130) from horticultural greenhouses in southern Spain was determined using qPCR and RT-PCR based techniques respectively. The offspring of these insects (N=200) was reared under laboratory conditions and analyzed to determine virus transmission. Overall, 54% of field-caught adults were infected by SeMNPV, 13.1% were infected by SeIV-1 and 7.7% were infected by SeIV-2. Multiple infections were also detected, with 8.4% of individuals harboring SeMNPV and one of the iflaviruses, whereas 2.3% of adults were infected by all three viruses. All the viruses were transmitted to offspring independently of whether the parental female harbored covert infections or not. Analysis of laboratory-reared insects in the adult stage revealed that SeIV-1 was significantly more prevalent than SeMNPV or SeIV-2, suggesting high transmissibility of SeIV-1. Mixed infection involving three viruses was identified in 6.5% of laboratory-reared offspring. We conclude that interspecific interactions between these viruses in co-infected individuals are to be likely frequent, both in the field, following applications of SeMNPV-based insecticides, or in laboratory colonies used for SeMNPV mass production.

Simultaneous occurrence of covert infections with small RNA viruses in the lepidopteran Spodoptera exigua.

Viral covert infections in invertebrates have been traditionally attributed to sublethal infections that were not able to establish an acute infection. Recent studies are revealing that, although true for some viruses, other viruses may follow the strategy of establishing covert or persistent infections without producing the death of the host. Recently, and due to the revolution in the sequencing technologies, a large number of viruses causing covert infections in all type of hosts have been identified. The beet armyworm, Spodoptera exigua (Lepidoptera: Noctuidae) is a worldwide pest that causes significant losses to agricultural and ornamental plant industries. In a previous project we used NGS to obtain a comprehensive transcriptome of the larval stage, revealing the presence of an important number of unigenes belonging to novel RNA viruses, most of them from the order Picornavirales. In order to characterize S. exigua viral complex, in this work we have completed the genomic sequences of two picorna-like viruses, and compared them to a SeIV1, a member of Iflaviridae previously described by our group. We performed additional studies to determine virus morphology, horizontal transmission, tissue and life stage distribution and abundance in the hosts. We discuss the role of virus persistent infections on insect populations.

Gender-mediated differences in vertical transmission of a nucleopolyhedrovirus.

With the development of sensitive molecular techniques for detection of low levels of asymptomatic pathogens, it becoming clear that vertical transmission is a common feature of some insect pathogenic viruses, and likely to be essential to virus survival when opportunities for horizontal transmission are unfavorable. Vertical transmission of Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) is common in natural populations of S. exigua. To assess whether gender affected transgenerational virus transmission, four mating group treatments were performed using healthy and sublethally infected insects: i) healthy males (H♂) × healthy females (H♀); ii) infected males (I♂) × healthy females (H♀); iii) healthy males (H♂) × infected females (I♀) and iv) infected males (I♂) × infected females (I♀). Experimental adults and their offspring were analyzed by qPCR to determine the prevalence of infection. Both males and females were able to transmit the infection to the next generation, although female-mediated transmission resulted in a higher prevalence of infected offspring. Male-mediated venereal transmission was half as efficient as maternally-mediated transmission. Egg surface decontamination studies indicated that the main route of transmission is likely transovarial rather than transovum. Both male and female offspring were infected by their parents in similar proportions. Incorporating vertically-transmitted genotypes into virus-based insecticides could provide moderate levels of transgenerational pest control, thereby extending the periods between bioinsecticide applications.

Intra- and intergenerational persistence of an insect nucleopolyhedrovirus: adverse effects of sublethal disease on host development, reproduction, and susceptibility to superinfection.

Sublethal infections by Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) are common in field populations of the beet armyworm (S. exigua, Hübner) in the Almerian horticultural region of Spain. Inoculation of second, third, and fourth instars with occlusion bodies (OBs) of an isolate (VT-SeAl1) associated with vertically transmitted infections resulted in 15 to 100% of sublethal infection in adult survivors, as determined by reverse transcription-PCR (RT-PCR) detection of viral DNA polymerase transcripts, and quantitative PCR (qPCR) targeted at the DNA polymerase gene. The prevalence of adult sublethal infection was positively related to the inoculum OB concentration consumed during the larval stage. Sublethal infections persisted in OB-treated insects for at least five generations. Viral transcripts were more frequently detected in adult insects than in third instars. qPCR analysis indicated a consistently higher prevalence of sublethal infection than RT-PCR. Sublethal infection was associated with significant reductions in pupal weight, adult emergence, fecundity, and fertility (egg hatch) and significant increases in larval development time and duration of the preoviposition period. Insects taken from a persistently infected experimental population were significantly more susceptible to the OB inoculum than control insects that originated from the same virus-free colony as the persistently infected insects. We conclude that OB treatment results in rapid establishment of sublethal infections that persist between generations and which incur costs in the development and reproductive capacity of the host insect.

Evidence for covert baculovirus infections in a Spodoptera exigua laboratory culture.

A laboratory culture of Spodoptera exigua was examined to assess covert (latent or persistent) baculovirus infections and spontaneous disease outbreaks. Two nucleopolyhedrovirus (NPV) species were found to be reactivated from a covert state in a laboratory culture of S. exigua to fully lethal forms. These were identified as S. exigua multinucleopolyhedrovirus (SeMNPV) and Mamestra brassicae NPV (MbNPV) using restriction enzyme analysis of purified viral DNA. Sequence data derived from both overtly and covertly virus-infected insects revealed highly conserved sequences for lef-8, lef-9 and polyhedrin gene sequence (98-100 % nucleotide identity to SeMNPV published sequence). By monitoring spontaneous overt infections and quantifying viral DNA (by quantitative-PCR) in asymptomatic individuals over two generations we identified fluctuating trends in viral DNA levels from covert SeMNPV and MbNPV within an S. exigua host population. Virus levels per insect life stage ranged from 3.51±0.101×10(5) to 0.29±0.036 pg (detection limit at 0.06 pg). Bioassays performed with this culture of larvae showed a differential susceptibility to SeMNPV-like or MbNPV-like viruses, with SeMNPV superinfections being extremely virulent. The data presented has broad implications relating to our understanding of transmission patterns of baculovirus in the environment and the role of covert infections in host-pathogen interaction dynamics.

Application of the PCR-RFLP method for the rapid differentiation of Spodoptera exigua nucleopolyhedrovirus genotypes.

Quality control during mass production of Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV), and studies on environmental fate following the use of this virus as a biological pesticide, would be facilitated by a rapid method for the detection and identification of isolates. A molecular biology tool was developed that combined the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) to differentiate SeMNPV isolates. Oligonucleotide primers were designed to amplify five variable SeMNPV genomic regions (V01, V02, V03, V04, V05). Four wild-type SeMNPV strains isolated from the United States (US2) and Spain (SP1, SP2, and SP3), and a laboratory cloned genotype (US1A), were analyzed with 36 different primer-endonuclease combinations. BglII digestion of the variable region 1 (V01) amplicon was the only combination that differentiated each of the five virus isolates tested, although genetic heterogeneity limited the discriminatory power of the technique. Six novel SeMNPV isolates originating from greenhouse soils in southern Spain were successfully identified using this method. As judged by sequence analysis, the V01 region, which comprises the homologous region 1 (hr1), is the most variable genomic region among the genotypes present in the Spanish isolates. This method constitutes a useful tool for processing large number of environmental samples and could be used to address environmental biosafety concerns.

Light-regulated asexual reproduction in Paecilomyces fumosoroseus.

The entomopathogenic fungus Paecilomyces fumosoroseus has been successfully used in the control of several insect pests. Asexually produced spores (conidia) are the means for dispersal and transmission of the entomopathogen; upon contact with the insect cuticle they germinate and penetrate the host. In model fungal systems it has been found that phototropism, resetting of the circadian rhythm, the induction of carotenogenesis and the development of reproductive structures are controlled by blue light. The effect of light quality on conidial yield of P. fumosoroseus was investigated. Incubation in total darkness resulted in continued vegetative growth and lack of reproductive structures. In contrast, growth of the fungus in continuous illumination or under a night-day regime resulted in prolific formation of conidiophores bearing abundant mature conidia. Conidiation was photoinduced in competent mycelia by a single pulse of blue light and colonies were competent only after they had grown at least 72 h under total darkness. The fluence-response curves generated with blue light indicated that the minimal fluence required for the photomorphogenetic response was 180 micro mol m(-2) and the half-maximal response was at 400 micro mol m(-2). A fluence of 540 micro mol m(-2) was enough to saturate the system, inducing the maximum production of 2.12x10(8) conidia per colony. Higher light intensities markedly decreased conidiation, suggesting the occurrence of a process of adaptation. The authors propose the existence of a dual light-perception system with at least two photoreceptors in P. fumosoroseus, one promoting and one inhibiting conidiation.

Effect of tinopal LPW on the insecticidal properties and genetic stability of the nucleopolyhedrovirus of Spodoptera exigua (Lepidoptera: Noctuidae).

The influence of an optical brightener, Tinopal LPW, on the activity of a purified genotype of the nucleopolyhedrovirus (SeMNPV) of the beet armyworm, Spodoptera exigua (Hübner), was determined in second to fifth instar (L2-L5) S. exigua. When mixed with viral occlusion bodies (OB) 1% Tinopal LPW significantly reduced the median lethal dose (LD50) of the virus in all instars compared with insects treated with SeMNPV alone. Levels of enhancement, as determined by LD50 values, ranged from 2.6- to 580-fold, depending on the instar. The greatest enhancement occurred on the two later instars, L4 (70-fold) and L5 (580-fold), which show a much higher resistance to SeMNPV infection than earlier instars. The median time to death (MTD) values were not significantly different in any instar among larvae treated with SeMNPV + Tinopal LPW and those treated with SeMNPV alone. Larval development in SeMNPV + Tinopal LPW treated larvae was retarded, in second and fourth instars, compared with controls or larvae treated with SeMNPV alone. The OB yields from SeMNPV treated larvae were almost 1.6-fold greater in second instars (9.3 x 10(6) OBs/larvae), and 1.9-fold greater in fourth instars (1.9 x 10(8) OBs/larvae), than those obtained in larvae treated with SeMNPV + Tinopal LPW. The addition of 1% Tinopal LPW to the virus suspension did not alter the genotypic composition of viral progeny during four successive passages of the virus.