Parasites of three commercially exploited bivalve mollusc species of the estuarine region of the Cachoeira river (Ilhéus, Bahia, Brazil)

This paper reports the parasites found in three commercially exploited bivalve molluscs (Mytella guyanensis, Anomalocardia brasiliana and Iphigenia brasiliana) of an estuarine region of Ilhéus, south of Bahia, Brazil (14°48′23′′S; 39°02′47′′W). Samples of 20 individuals of each species were collected fortnightly from August 2005 to August 2006. A total of 1480 individuals was collected and processed by standard histologic techniques; the histologic sections were stained with Harris haematoxylin and eosin and examined with light microscope. The water temperature in the study area varied from 24 to 30.5 °C and the salinity from 0 to 23 ppt. Remarkable differences were found in the parasitic community between the three mollusc species involved in the study, which occupied different habitats in the estuarine region of the Cachoeira river. The following parasites were found: intracellular rickettsia-like colonies in digestive epithelia; intracellular gregarine Nematopsis sp. in gills, mantle, gonad, digestive gland and foot muscle; sporocysts of a Bucephalidae trematode in gonads, mantle, gills, digestive gland and foot; unidentified digenetic metacercariae in digestive gland and gonad; metacestodes of Tylocephalum sp. in connective tissue in the digestive gland and in gonad; and an unidentified metazoan in mantle and intestinal lumen. No significant temporal variation in the prevalence of any parasite was detected, which could be due to the narrow temperature range of the region and the absence of patterns of salinity and rainfall variation through the year. The infestation by sporocyst was the only pathological threat detected for the studied populations because of its potential for host castration. The low infection intensity and/or prevalence of the other parasites and the lack of obvious lesions suggest that there is no other serious pathological risk for the studied mollusc populations.     

A life table for the cinnabar mothTyria jacobaeae,in Oregon

The cinnabar moth,Tyria jacobaeae L. (Arctiidae), was introduced into Oregon in 1960 against the weed tansy ragwort,Senecio jacobaea L., and in 1970 an intensive study of a population of this biological control agent was initiated. Field sampling methods were devised, and laboratory investigations of feeding and larval development were conducted. Results of the study were analyzed and reported as partial life tables, where possible mortality factors were identified and quantified. The most important mortality factor in both 1970 and 1971 was starvation after defoliation of host plants. Other factors identified included pupal death, emergence failure, egg predation, and larval ingestion of eggs.     

Stage-specific mortality, fecundity, and population changes in Cassida rubiginosa (Coleoptera: Chrysomelidae) on wild thistle

Cassida rubiginosa Müller (Coleoptera: Chrysomelidae), one of the most conspicuous defoliators of thistle weeds, is capable of severely damaging thistle leaves; however, populations rarely reach sufficient density for effective thistle control under natural conditions. To investigate the impact of natural mortality factors on C. rubiginosa populations, life table studies were conducted between 1996 and 1998 in Kanazawa, Japan. Egg mortality, mortality in early larvae, and lost fertility contributed strongly to total generational mortality in every year studied. Egg mortality was primarily attributable to parasitism by wasps of the genus Anaphes, and the impact of predation and egg inviability was small. Mortality factors that affected the larval and pupal stages were largely unknown. Under field conditions, females only realized approximately 8.1?C13.7?% of their potential fecundity, varying from 36.0 to 61.4 eggs per individual. Since annual changes in lost fertility exhibited a similar pattern to those in generational mortality, fertility loss might be the key factor driving C. rubiginosa populations. These results suggest that reproduction is the most important process that determines the level and fluctuation of the C. rubiginosa population.     

Single Nucleotide Variants in the Protein C Pathway and Mortality in Dialysis Patients

Background

The protein C pathway plays an important role in the maintenance of endothelial barrier function and in the inflammatory and coagulant processes that are characteristic of patients on dialysis. We investigated whether common single nucleotide variants (SNV) in genes encoding protein C pathway components were associated with all-cause 5 years mortality risk in dialysis patients.

Methods

Single nucleotides variants in the factor V gene (F5 rs6025; factor V Leiden), the thrombomodulin gene (THBD rs1042580), the protein C gene (PROC rs1799808 and 1799809) and the endothelial protein C receptor gene (PROCR rs867186, rs2069951, and rs2069952) were genotyped in 1070 dialysis patients from the NEtherlands COoperative Study on the Adequacy of Dialysis (NECOSAD) cohort) and in 1243 dialysis patients from the German 4D cohort.

Results

Factor V Leiden was associated with a 1.5-fold (95% CI 1.1–1.9) increased 5-year all-cause mortality risk and carriers of the AG/GG genotypes of the PROC rs1799809 had a 1.2-fold (95% CI 1.0–1.4) increased 5-year all-cause mortality risk. The other SNVs in THBD, PROC, and PROCR were not associated with 5-years mortality.

Conclusion

Our study suggests that factor V Leiden and PROC rs1799809 contributes to an increased mortality risk in dialysis patients.     

The Clinical Characteristics,Carbapenem Resistance,and Outcome of Acinetobacter Bacteremia According to Genospecies

Background

Few clinical data are available on the relationship between genospecies and outcome of Acinetobacter bacteremia, and the results are inconsistent. We performed this study to evaluate the relationship between genospecies and the outcome of Acinetobacter bacteremia.

Methods

Clinical data from 180 patients who had Acinetobacter bacteremia from 2003 to 2010 were reviewed retrospectively. The genospecies were identified by rpoB gene sequence analysis. The clinical features and outcomes of 90 patients with A. baumannii bacteremia were compared to those of 90 patients with non-baumannii Acinetobacter bacteremia (60 with A. nosocomialis, 17 with Acinetobacter species “close to 13 TU”, 11 with A. pittii, and two with A. calcoaceticus).

Results

A. baumannii bacteremia was associated with intensive care unit-onset, mechanical ventilation, pneumonia, carbapenem resistance, and higher APACHE II scores, compared to non-baumannii Acinetobacter bacteremia (P<0.05). In univariate analyses, age, pneumonia, multidrug resistance, carbapenem resistance, inappropriate empirical antibiotics, higher APACHE II scores, and A. baumannii genospecies were risk factors for mortality (P<0.05). Multivariate analysis revealed A. baumannii genospecies (OR, 3.60; 95% CI, 1.56–8.33), age, pneumonia, and higher APACHE II scores to be independent risk factors for mortality (P<0.05).

Conclusion

A. baumannii genospecies was an independent risk factor for mortality in patients with Acinetobacter bacteremia. Our results emphasize the importance of correct species identification of Acinetobacter blood isolates.     

No Association between Loss-of-Function Mutations in filaggrin and Diabetes,Cardiovascular Disease,and All-Cause Mortality

Background

Common loss-of-function mutations in the filaggrin gene (FLG) are a major predisposing risk factor for atopic disease due to reduced epidermal filaggrin protein levels. We previously observed an association between these mutations and type 2 diabetes and hypothesized that an inherited impairment of skin barrier functions could facilitate low-grade inflammation and hence increase the risk of diabetes and cardiovascular disease. We examined the association between loss-of-function mutations in FLG and diabetes, stroke, ischemic heart disease (IHD), and all-cause mortality in the general population.

Methods

The R501X and 2282del4 loss-of function mutations in FLG were genotyped in four Danish study populations including a total of 13373 adults aged 15-77 years. Two of the studies also genotyped the R2447X mutation. By linkage to Danish national central registers we obtained information for all participants on dates of diagnoses of diabetes, stroke, and IHD, as well as all-cause mortality. Data were analyzed by Cox proportional hazard models and combined by fixed effect meta-analyses.

Results

In meta-analyses combining the results from the four individual studies, carriage of loss-of-function mutations in FLG was not associated with incident diabetes (hazard ratio (HR) (95% confidence intervals (CI)) = 0.95 (0.73, 1.23), stroke (HR (95% CI) = 1.27 (0.97, 1.65), ischemic heart disease (HR (95%CI) = 0.92 (0.71, 1.19), and all-cause mortality (HR (95%CI) = 1.02 (0.83, 1.25)). Similar results were obtained when including prevalent cases in logistic regression models.

Conclusion

Our results suggest that loss-of-function mutations in FLG are not associated with type 2 diabetes, cardiovascular disease, and all-cause mortality. However, larger studies with longer follow-up are needed to exclude any associations.     

The Aspergillus fumigatus sitA Phosphatase Homologue Is Important for Adhesion,Cell Wall Integrity,Biofilm Formation,and Virulence

Aspergillus fumigatus is an opportunistic pathogenic fungus able to infect immunocompromised patients, eventually causing disseminated infections that are difficult to control and lead to high mortality rates. It is important to understand how the signaling pathways that regulate these factors involved in virulence are orchestrated. Protein phosphatases are central to numerous signal transduction pathways. Here, we characterize the A. fumigatus protein phosphatase 2A SitA, the Saccharomyces cerevisiae Sit4p homologue. The sitA gene is not an essential gene, and we were able to construct an A. fumigatus null mutant. The ΔsitA strain had decreased MpkA phosphorylation levels, was more sensitive to cell wall-damaging agents, had increased β-(1,3)-glucan and chitin, was impaired in biofilm formation, and had decreased protein kinase C activity. The ΔsitA strain is more sensitive to several metals and ions, such as MnCl₂, CaCl₂, and LiCl, but it is more resistant to ZnSO₄. The ΔsitA strain was avirulent in a murine model of invasive pulmonary aspergillosis and induces an augmented tumor necrosis factor alpha (TNF-α) response in mouse macrophages. These results stress the importance of A. fumigatus SitA as a possible modulator of PkcA/MpkA activity and its involvement in the cell wall integrity pathway.     

Interannual variation in rainfall,drought stress and seedling mortality may mediate monodominance in tropical flooded forests

Flood tolerance is commonly regarded as the main factor explaining low diversity and monodominance in tropical swamps. In this study we examined seedling mortality in relation to seasonality, i.e., flooding versus drought, of the dominant tree species (Prioria copaifera), and three associated species (Pterocarpus officinalis, Carapa guianensis and Pentaclethra macroloba), in seasonally flooded forests (SFF) in Darien, Panama. Seedling mortality differed among species, years and seasons. Prioria seedlings experienced the lowest overall mortality, and after 3 years many more Prioria seedlings remained alive than those of any of the associated species. In general, within species, larger seedlings had greater survival. Seed size, which can vary by close to 2 orders of magnitude in Prioria, had a confounding effect with that of topography. Large-seeded Prioria seedlings experienced 1.5 times greater mortality than small-seeded seedlings, as large-seeded Prioria seedlings were more likely to be located in depressions. This finding suggests that seed size, plant size and topography are important in understanding SFF regeneration. For all species, seedling mortality was consistently greater during the dry season than during flooding. For Prioria, dry season seedling mortality was correlated with drought stress, that is, high mortality during the long El Niño dry season of 1998 and the normal dry season of 2000, but very low dry season mortality during the mild dry season of 1999. Prioria’s ability to dominate in seasonally flooded forest of Central America is partly explained by its low drought-related mortality in comparison to associated species.     

Modelling the population dynamics of Penilia avirostris (Branchiopoda,Ctenopoda) in a tropical bay

An ecological model for the simulation of the population dynamics of the cladoceran Penilia avirostris in Guanabara Bay, a tropical Brazilian bay, was developed. The simulated curve gave a good fit, in time and intensity, to the exponential increase and decrease in densities of P. avirostris during the March-July 2000 period. The densities of embryos, young individuals, males, and parthenogenic and gamogenic females were the state variables. Parameters of the model were varied within the range of field and literature data. Predation was considered as the main factor affecting mortality, the death rate being a function of the density of chaetognaths, the dominant invertebrate predator in Guanabara Bay. Input of resting eggs into the model as a “seed” source of embryos provided a good fit to the exponential increase of Penilia density. The observed sharp decreases and collapses of the population could not be explained by mortality or a shift from parthenogenic to gamogenic reproduction only. To provide an explanation, it was necessary to introduce an output forcing function, which probably represents physical factors such as water mass exchanges by tide- and wind-driven currents.     

Novel Host-Related Virulence Factors Are Encoded by Squirrelpox Virus,the Main Causative Agent of Epidemic Disease in Red Squirrels in the UK

Squirrelpox virus (SQPV) shows little evidence for morbidity or mortality in North American grey squirrels (Sciurus carolinensis), in which the virus is endemic. However, more recently the virus has emerged to cause epidemics with high mortality in Eurasian red squirrels (S. vulgaris) in Great Britain, which are now threatened. Here we report the genome sequence of SQPV. Comparison with other Poxviridae revealed a core set of poxvirus genes, the phylogeny of which showed SQPV to be in a new Chordopoxvirus subfamily between the Molluscipoxviruses and Parapoxviruses. A number of SQPV genes were related to virulence, including three major histocomaptibility class I homologs, and one CD47 homolog. In addition, a novel potential virulence factor showing homology to mammalian oligoadenylate synthetase (OAS) was identified. This family of proteins normally causes activation of an endoribonuclease (RNaseL) within infected cells. The putative function of this novel SQPV protein was predicted in silico.     

Prognostic factors in infective endocarditis in general hospitals in the Netherlands

Introduction

Despite advances in treatment, infective endocarditis (IE) still ranks amongst the most lethal infectious diseases. We sought to determine prognostic factors in general hospitals in the Netherlands as research in this setting is scarce.

Results

Between 2004 and 2011, we identified 216 cases of IE, 30.1?% of which were prosthetic valve IE. This leads to an annual incidence of IE of 5.7 new cases per 100,000 persons per year. Women were less likely to undergo surgical intervention (OR = 1.96, 95?% CI 1.06–3.61, p = 0.031). Also, ageing was an independent prognostic factor for not receiving surgery in a multivariate analysis (annual OR = 1.04, 95?% CI 1.02–1.06, p < 0.001). Female sex was a prognostic factor for mortality (OR = 2.35, 95?% CI 1.29–4.28, p = 0.005). Age was also an independent prognostic factor for mortality (OR = 1.05, 95% CI 1.03–1.08, p < 0.001). Conservative treatment was a prognostic factor for mortality (OR = 3.39, 95?% CI 1.80–6.38, p < 0.001) whereas surgical intervention was an independent prognostic factor for adverse events (OR = 3.03, 95% CI 1.64–5.55, p < 0.001). Staphylococcus aureus was an independent prognostic factor for adverse events (OR = 2.05, 95?% CI 1.10–3.84, p = 0.024) but not for mortality.

Conclusion

This study shows that endocarditis in general hospitals has a high rate of morbidity and mortality. Even when treated, it ranks as one of the most lethal infectious diseases in the Netherlands, especially in women and the elderly.

     

Halobacteriovorax,an underestimated predator on bacteria: potential impact relative to viruses on bacterial mortality

Predation on bacteria and accompanying mortality are important mechanisms in controlling bacterial populations and recycling of nutrients through the microbial loop. The agents most investigated and seen as responsible for bacterial mortality are viruses and protists. However, a body of evidence suggests that predatory bacteria such as the Halobacteriovorax (formerly Bacteriovorax), a Bdellovibrio-like organism, contribute substantially to bacterial death. Until now, conclusive evidence has been lacking. The goal of this study was to better understand the contributors to bacterial mortality by addressing the poorly understood role of Halobacteriovorax and how their role compares with that of viruses. The results revealed that when a concentrated suspension of Vibrio parahaemolyticus was added into microcosms of estuarine waters, the native Halobacteriovorax were the predators that responded first and most rapidly. Their numbers increased by four orders of magnitude, whereas V. parahaemolyticus prey numbers decreased by three orders of magnitude. In contrast, the extant virus population showed little increase and produced little change in the prey density. An independent experiment with stable isotope probing confirmed that Halobacteriovorax were the predators primarily responsible for the mortality of the V. parahaemolyticus. The results show that Halobacteriovorax have the potential to be significant contributors to bacterial mortality, and in such cases, predation by Halobacteriovorax may be an important mechanism of nutrient recycling. These conclusions add another dimension to bacterial mortality and the recycling of nutrients.     

Mortality factors affecting the cabbage seedpod weevil,Ceutorhynchus obstrictus (Marsham), in its area of origin: A life table analysis

The cabbage seedpod weevil, Ceutorhynchus obstrictus (Marsham) (Coleoptera: Curculionidae), is a widely distributed invasive pest of cruciferous crops in North America. Control measures rely mostly on the application of insecticides but alternative control strategies such as classical biological control are under evaluation. To investigate the impact of parasitoids and other mortality factors on C. obstrictus populations, life table studies were conducted between 2005 and 2007 in 13 winter oilseed rape fields in Switzerland, part of the native range. Under field conditions females only realized approximately 50% of their potential lifetime fecundity, varying between 96 and 631 eggs per individual. Total generational mortality was higher than 99.6% in each year. Overwintering mortality of adults was the major population limiting factor, contributing approximately 50% to the overall generational mortality of C. obstrictus, whereas factors acting on the immature stages were responsible for the remaining 50%. Among the mortality factors of the immature stages, egg, larval and pupal mortality contributed 9–12%, 25–28% and 4–6% to the generational mortality, respectively. Larval ecto-parasitism on its own accounted for 7–15% of the generational mortality. Comparison of life table data presented here with that from North America will be invaluable for elucidating the mortality factors that regulate C. obstrictus populations in Europe, the region of origin.     

Quantifying Policy Options for Reducing Future Coronary Heart Disease Mortality in England: A Modelling Study

Aims

To estimate the number of coronary heart disease (CHD) deaths potentially preventable in England in 2020 comparing four risk factor change scenarios.

Methods and Results

Using 2007 as baseline, the IMPACT_SEC model was extended to estimate the potential number of CHD deaths preventable in England in 2020 by age, gender and Index of Multiple Deprivation 2007 quintiles given four risk factor change scenarios: (a) assuming recent trends will continue; (b) assuming optimal but feasible levels already achieved elsewhere; (c) an intermediate point, halfway between current and optimal levels; and (d) assuming plateauing or worsening levels, the worst case scenario. These four scenarios were compared to the baseline scenario with both risk factors and CHD mortality rates remaining at 2007 levels. This would result in approximately 97,000 CHD deaths in 2020. Assuming recent trends will continue would avert approximately 22,640 deaths (95% uncertainty interval: 20,390-24,980). There would be some 39,720 (37,120-41,900) fewer deaths in 2020 with optimal risk factor levels and 22,330 fewer (19,850-24,300) in the intermediate scenario. In the worst case scenario, 16,170 additional deaths (13,880-18,420) would occur. If optimal risk factor levels were achieved, the gap in CHD rates between the most and least deprived areas would halve with falls in systolic blood pressure, physical inactivity and total cholesterol providing the largest contributions to mortality gains.

Conclusions

CHD mortality reductions of up to 45%, accompanied by significant reductions in area deprivation mortality disparities, would be possible by implementing optimal preventive policies.     

Effect of litter birth weight standardization before first suckling on colostrum intake,passive immunization,pre-weaning survival,and growth of the piglets

Within-litter variation in birth weight is a relevant factor in pig production. This study aimed at comparing pre-weaning mortality, colostrum intake (CI), passive immunization, and growth of piglets from litters of uniform (UN) or heterogeneous (HET) birth weights. The study included 52 multiparous sows (Large White × Landrace) and their litters. Two types of litters were constituted based on birth weight, namely: UN or HET, the control group, using piglets from two to three sows farrowing approximately at the same time. At birth, piglets were weighed, identified, and placed in a box under an IR lamp. At the end of farrowing, piglets were re-weighed and allotted to groups UN or HET (12 per litter) with average weights of 1 394 and 1 390 g, respectively, and allowed to suckle (time 0). They were re-weighed 24 h later to estimate CI and sows' colostrum yield. At time 0, the average intra-litter CV (%) in weight of experimental litters were 9.3 ± 0.8 (SEM) and 27.8 ± 0.7 in groups UN and HET, respectively (P < 0.001). At 2 days of age, blood samples were taken from the piglets of 11 litters five UN and six HET) and serum Immunoglobulin G (IgG) contents were determined. Mean CI/piglet/litter was similar in both groups, that is, 415 ± 13 in UN and 395 ± 13 g in HET (P = 0.28), but was less variable in UN litters (CV = 22.4 ± 2 vs 36.0 ± 2%, P < 0.001). The IgG levels at 2 days of age were higher in piglets from UN litters (22.5 ± 0.8 vs 18.4 ± 0.7 g/l; P < 0.001) but the CV of IgG levels was not different between litter type (P = 0.46). Mortality up to 21 days of age was lower in UN litters (6.4 vs 11.9%, P = 0.03). The BW at 21 days was not different between litter type (P = 0.25) but it was less variable among piglets from UN litters (CV: 17.1 ± 1.3 vs 25.7 ± 1.3%; P = 0.01). Results reveal that CI is less variable and mortality is lower in piglets from litters of UN birth weight. The results infer that genetic improvement to decrease variation in birth weight within-litter could have a positive effect on homogeneous CI and thus contribute to reducing piglet mortality.     

Invasive Non-typhoidal Salmonella Infections in Asia: Clinical Observations,Disease Outcome and Dominant Serovars from an Infectious Disease Hospital in Vietnam

Invasive non-typhoidal Salmonella (iNTS) infections are now a well-described cause of morbidity and mortality in children and HIV-infected adults in sub-Saharan Africa. In contrast, the epidemiology and clinical manifestations of iNTS disease in Asia are not well documented. We retrospectively identified >100 cases of iNTS infections in an infectious disease hospital in Southern Vietnam between 2008 and 2013. Clinical records were accessed to evaluate demographic and clinical factors associated with iNTS infection and to identify risk factors associated with death. Multi-locus sequence typing and antimicrobial susceptibility testing was performed on all organisms. Of 102 iNTS patients, 71% were HIV-infected, >90% were adults, 71% were male and 33% reported intravenous drug use. Twenty-six/92 (28%) patients with a known outcome died; HIV infection was significantly associated with death (p = 0.039). S. Enteritidis (Sequence Types (ST)11) (48%, 43/89) and S. Typhimurium (ST19, 34 and 1544) (26%, 23/89) were the most commonly identified serovars; S. Typhimurium was significantly more common in HIV-infected individuals (p = 0.003). Isolates from HIV-infected patients were more likely to exhibit reduced susceptibility against trimethoprim-sulfamethoxazole than HIV-negative patients (p = 0.037). We conclude that iNTS disease is a severe infection in Vietnam with a high mortality rate. As in sub-Saharan Africa, HIV infection was a risk factor for death, with the majority of the burden in this population found in HIV-infected adult men.     

Drought stress as a mortality factor in two pairs of sympatric species of Collembola at Spitsbergen, Svalbard

Desiccation resistance was investigated experimentally in two species pairs of Collembola: Hypogastrura viatica and H. longispina, and Folsomia sexoculata and F. quadrioculata. A previous field study in Ny-Ålesund, Svalbard, showed clear habitat segregation between the species, related to two concomitant gradients of habitat cover and soil moisture. H. longispina and F. sexoculata inhabit areas with high habitat cover and soil moisture, whereas F. quadrioculata is mainly found in drier areas with high cover and H. viatica exploits the whole range of humidities/habitat cover. The desiccation experiments were aimed at testing if drought is likely to be a limiting factor for the distribution of H.?longispina and F. sexoculata. Drought was induced experimentally by testing different temperatures at a constant relative humidity. Temperature recordings from the field showed that temperatures within the range tested in the experiments occur naturally. H. longispina was highly drought sensitive compared to H. viatica, and desiccation stress probably acts as a limiting factor for its distribution in the area. F. sexoculata, was, however, much more resistant to desiccation than F. quadrioculata. For F. sexoculata, resistance to desiccation may show a trade-off in favour of tolerating a wider range of humidities, or be the result of a cuticular adaptation related to long dispersal distances and/or tolerance to submergence. For F. quadrioculata, desiccation may be an important mortality factor (but not limiting), contributing to high between-population variability in density and demography.     

The influence of starvation on mortality,development, and protein content in parasitized and unparasitized Tribolium castaneum

The effects of starvation on mortality, development, and protein content in Nosema whitei-infected and uninfected Tribolium castaneum were investigated. T. castaneum larvae, starved for 4, 6, 8, and 10 days postinfection, showed an increase in larval mortality. Pupal mortality also increased, producing a decrease in adult emergence. Starvation of larvae for 6 days or more delayed development and the average time to adult emergence increased. These effects tended to be more marked in Nosema-infected larvae. No consistent pattern of weight changes was observed in either the uninfected or infected pupae and adults. Infected T. castaneum larvae showed a significant decrease in protein compared to controls. Starvation apparently does not aggravate this condition nor does it have any significant effects on the total hemolymph protein content of uninfected and infected larvae.     

Susceptibility of the spruce budworm, Choristoneura fumiferana, and the white-marked tussock moth, Orgyia leucostigmata, to Bacillus thuringiensis: Chemical insecticide combinations

Bacillus thuringiensis mixed with the organophosphate insecticides, fenitrothion (Sumithion), Gardona^®, and Orthene^®, or the synthetic pyrethroid, SBP 1382, was incorporated into synthetic diet and fed larvae of the spruce budworm, Choristoneura fumiferana, and the white-marked tussock moth, Orgyia leucostigma. Mortality was highest when larvae were fed combinations of low concentrations of the insecticides and low to moderate concentrations of the pathogen. The data indicated that applications of a B. thuringiensis dosage expected to produce about 45% mortality of third and fourth instar larvae of the spruce budworm combined with a dosage of fenitrothion causing about 40% mortality or a dosage of Orthene causing from 5 to 25% mortality should result in low budworm survival. With a B. thuringiensis dosage causing 20–60% mortality combined with a fenitrothion dosage causing 15–50% mortality or a sublethal dosage of Gardona, a low survival rate of young white-marked tussock moth larvae may be expected.     

The effect of population density of parasitePerisierola nephantidis [Hym.: Bethylidae] on the mortality of coconut caterpillar,Nephantis serinops [Lep.: Cryptophagidae]

The population density ofPerisierola nephantidis Mues. acts as key mortality factor in the biological control ofNephantis serinopa Meyrick. The mortality ofN. serinopa was directly proportional to the density of parasiteP. nephantidis and recorded a maximum of 96% at 1∶8 ratio of host to parasite at constant population of host. A significant inverse density-dependent action ofP. nephantidis was observed under various density ofNephantis larvae at a constant population of the parasite.