Evaluating different carriers of Metarhizium brunneum F52 microsclerotia for control of adult Asian longhorned beetles (Coleoptera: Cerambycidae)

Microsclerotia (MS) of Metarhizium brunneum strain F52 (Hypocreales: Clavicipitaceae) were processed as granules using three carriers: kaolin clay, microcrystalline cellulose (MCC), or diatomaceous earth (DE). In a series of experiments aimed at comparing viable conidial production, each MS carrier type was hydrated using a decreasing range of water activities on glycerol or polyethylene glycol (PEG200)-amended media. Conidial density and percent germination of conidia declined significantly as water activity was lowered. All three carrier types produced >2–6?×?10⁹ viable conidia/gram at higher water activities (а_w >0.987) but were still capable of producing 2.9?×?10⁷?±?1.6?×?10⁶ conidia/g (30% glycerol а_w?=?0.883) and 1.9?×?10⁷?±?6.5?×?10⁶ conidia/g (30% PEG200 а_w?=?0.924) at the lowest tested water activities. MS carrier types were sprayed onto 0.4?m length logs with or without hydromulch formulation. The median survival times of Asian longhorned beetles, Anoplophora glabripennis (Coleoptera: Cerambycidae), exposed by climbing double the length of the logs of hydromulch-treated bark, were 16.5–20.5?d while beetles exposed to logs without hydromulch formulation had median survival times of 22–25.5?d. Overall, experiments showed that there were few biologically significant differences between the MS carrier types.     

Development of an experimental laboratory fertilization protocol for the South African abalone,Haliotis midae (Linnaeus 1758)

In this study, effective gamete concentrations, egg viability, and fertilization volumes were evaluated for Haliotis midae (L.). Sperm concentrations between 5?×?10³ and 5?×?10⁴?mL^?1 (p?>?0.05) consistently resulted in high hatch-out rates (96?±?1%). At concentrations higher than 5?×?10⁵?mL^?1, hatch-out rates decreased to 69?±?7% (p??1 resulted in high fertilization rates, with 50?eggs?mL^?1 being the ideal concentration for fertilization in H. midae. Egg viability was consistently high up to 100?min post-spawning, with a decrease in hatch-out success, when eggs were fertilized 120?min post-spawning. Fertilization volumes did not affect successful hatch-out. The results from this study can be implemented by South African abalone farms to increase hatch-out rates and subsequent culture. It can also be used as basis for the development of fertilization protocols in other marine invertebrate species.     

Sporulation,storage and infectivity of obligate aphid pathogen Pandora nouryi grown on novel granules of broomcorn millet and polymer gel

Aims: Producing granular cultures of obligate aphid pathogen Pandora nouryi for improved sporulation and storage. Methods and Results: Small millet–gel granules were made of the mixtures of 80–95% millet powder with 5–20% polymer gel (polyacrylamide, polyacrylate or acrylate‐acrylamide copolymer) and inoculated with mycelia at 30 mg biomass g^?1 dry granules plus 87·5% water, followed by static incubation at 20°C for 4–12 days. The fungus grew well on 12 preparations but best on that including 10% copolymer. An 8‐day culture of this preparation discharged maximally 58·5 × 10⁴ conidia mg^?1 granule at 100% RH and was capable of ejecting conidia at the nonsaturated regimes of 86–97% RH. During storage at 6°C, granular cultures with >85% water content had twofold longevity (120 days) and half‐decline period (34–36 days) of those stored at room temperature. The steadily high water content preserved the cultures better than that decreasing at 6°C. However, conidia from 70‐day‐stored granules were less infective to Myzus persicae nymphs than those from fresh ones based on their LC₅₀s. Conclusions: The millet–gel granules had higher sporulation capacity than reported Pandora cultures and a capability of spore discharge at nonsaturated humidity. Significance and Impact of the Study: The granular cultures are more useful for aphid control.     

Effectiveness of Metarhizium anisopliae formulations against dengue vectors under laboratory and field conditions

The oviposition behaviour of Aedes aegypti and the effectiveness of Metarhizium anisopliae conidia formulated in water or oil-in-water against A. aegypti adults and eggs were tested in multi-choice and no-choice tests in oviposition devices under laboratory conditions. Both females and males rested in the devices, regardless of the formulation, and were not repelled by the presence of conidia (up to 10⁶?conidia/cm²) without oil or formulated with oil on treated filter paper arranged in the device. However, at higher oil concentrations (≥0.1?μl/cm²), regardless of the presence of conidia, the number of eggs laid by gravid females on the filter paper dropped. The susceptibility of adults, especially of males, to fungal infection increased up to a 15-day incubation. An elevated number of larvae (≥41%) eclosed from eggs laid on the moistened filter paper in the device even without submersion of eggs in water, and these larvae subsequently died. In the laboratory, 1?μl/cm² oil combined with 10⁶?conidia/cm² clearly reduced eclosion to 1.8% after submersion of eggs in water compared to ≥13% eclosion in the control. In field tests in Goiânia, Brazil, eclosion of aedine larvae from eggs laid on filter paper previously treated with oil-in-water formulated conidia dropped to between 0% and 36% compared to 22–50% in the control. Promising results of laboratory and field tests with M. anisopliae formulated in water or oil-in-water and tested in a device emphasised the effectiveness of a fungus-based formulation for aedine mosquitoes in peridomestic areas.     

Comprehensive optimization of composite cryoprotectant for Saccharomyces boulardii during freeze-drying and evaluation of its storage stability

Abstract

Saccharomyces boulardii (S. boulardii) is widely adopted in the diarrhea treatment for humans or livestock, so guaranteeing the survival rate of S. boulardii is the critical issue during freeze-drying process. In this study, the survival rate of S. boulardii with composite cryoprotectants during freeze-drying procedure and the subsequent storage were investigated. With the aid of response surface method, the composite cryoprotectants were comprehensively optimized to be lactose of 21.24%, trehalose of 22.00%, and sodium glutamate of 4.00%, contributing to the supreme survival rate of S. boulardii of 64.22?±?1.35% with the viable cell number of 9.5?±?0.07?×?10⁹ CFU/g, which was very close to the expected rate of 65.55% with a number of 9.6?×?10⁹ CFU/g. The accelerated storage test demonstrated that the inactivation rate constant of the freeze-dried S. boulardii powder was k_?18?=?8.04?×?10^?6. In addition, the freeze-dried goat milk powder results exhibited that the inactivation rate constants were k₄?=?4.48?×?10^?4 and k₂₅?=?9.72?×?10^?3 under 4 and 25?°C, respectively. This work provides a composite cryoprotectant formulation that has a good protective effect for the probiotic S. boulardii during freeze-drying process, possessing the potential application prospect in food, medicine, and even feed industry.     

Eddy covariance captures four‐phase crassulacean acid metabolism (CAM) gas exchange signature in Agave

Mass and energy fluxes were measured over a field of Agave tequilana in Mexico using eddy covariance (EC) methodology. Data were gathered over 252 d, including the transition from wet to dry periods. Net ecosystem exchanges (F_N,EC) displayed a crassulacean acid metabolism (CAM) rhythm that alternated from CO₂ sink at night to CO₂ source during the day, and partitioned canopy fluxes (F_A,EC) showed a characteristic four‐phase CO₂ exchange pattern. Results were cross‐validated against diel changes in titratable acidity, leaf‐unfurling rates, energy exchange fluxes and reported biomass yields. Projected carbon balance (g C m^?2 year^?1, mean ± 95% confidence interval) indicated the site was a net sink of ?333 ± 24, of which contributions from soil respiration were +692 ± 7, and F_A,EC was ?1025 ± 25. EC estimated biomass yield was 20.1 Mg (dry) ha^?1 year^?1. Average integrated daily F_A,EC was ?234 ± 5 mmol CO₂ m^?2 d^?1 and persisted almost unchanged after 70 d of drought conditions. Regression analyses were performed on the EC data to identify the best environmental predictors of F_A. Results suggest that the carbon acquisition strategy of Agave offers productivity and drought resilience advantages over conventional semi‐arid C3 and C4 bioenergy candidates.     

Effect of host plant on susceptibility of whitefly Bemisia tabaci (Homoptera: Aleyrodidae) to the entomopathogenic fungus Beauveria bassiana (Ascomycota: Hypocreales)

We determined host plant effect on susceptibility of whitefly Bemisia tabaci to the entomopathogenic fungus Beauveria bassiana under controlled conditions. Insects were reared on cucumber, eggplant, tomato or cabbage. Fungal suspensions of 1×10⁴, 10⁵, 10⁶, 10⁷ and 10⁸ conidia/mL were applied on second-instar nymphs. Nymphal survival significantly differed among different host plant species on which the nymphs were reared. Ten days after inoculation with 1×10⁸ conidia/mL, percent survival was 4.2±0.7, 9.6±0.4, 13.4±0.8, and 24.3±0.9% on cucumber, eggplant, tomato and cabbage, respectively. Average survival times of nymphs were also significantly influenced by host plant species. After inoculation with 1×10⁸ conidia/mL, survival times were 4.8±0.15, 6.0±0.11, 5.7±0.13, and 6.2±0.08 days for nymphs reared on cucumber, eggplant, tomato, and cabbage, respectively. Virulence also differed depending on host plant species; 10 days after inoculation, LC₅₀ values were 4.6×10⁴, 1.6×10⁵, 4.2×10⁵ and 2.1×10⁶ conidia/mL on cucumber, eggplant, tomato and cabbage, respectively. Nymphs on cucumber showed highest susceptibility.     

Prostaglandin Endoperoxide H Synthase-2 (PGHS-2) Variants and Risk of Obesity and Microvascular Dysfunction Among Tunisians: Relevance of rs5277 (306G/C) and rs5275 (8473T/C) Genetic Markers

The purpose of this study was to determine the impact of six PGHS-2 genetic variants on obesity development and microvascular dysfunction. The study included 305 Tunisian subjects (186 normal weights, 35 overweights and 84 obeses). PCR analyses were used for allelic discrimination between polymorphisms. Prostaglandin (PGE2, PGI2), leptin, and matrix metalloproteinase (MMP1, 2, 3, 9) levels were evaluated by ELISA. Fatty acid composition was performed by gas chromatography–mass spectrometry. Our results revealed that subjects carrying the PGHS-2 306CC (rs5277) and 8473CC (rs5275) genotypes present higher anthropometric values compared to wild-type genotypes (306GG, BMI (Kg/m²): 27.11?±?0.58; WC (cm): 93.09?±?1.58; 306CC, BMI: 33.83?±?2.46; WC: 109.93?±?5.41; 8473TT, BMI: 27.75?±?0.68; WC: 93.96?±?1.75; 8473CC, BMI: 33.72?±?2.2; WC: 117.89?±?2.94). A reduced microvascular reactivity and a higher PGE2 level were also found in individuals with the 306CC and 8473CC genotypes in comparison to 306GG and 8473TT carriers (306GG, Peak Ach-CVC (PU/mmHg): 0.46?±?0.03; PGE2 (pg/ml): 7933.1?±?702; 306CC, Peak Ach-CVC: 0.24?±?0.01; PGE2: 13,380.3?±?966.2; 8473TT, Peak Ach-CVC: 0.48?±?0.05; PGE2: 7086.41?±?700.31; 8473CC, Peak Ach-CVC: 0.23?±?0.01; PGE2: 13,175.7?±?1165.8). Fatty acid analysis showed a significant increase of palmitic acid (PA) (34.2?±?2.09 vs. 16.82%?±?1.76, P?<?0.001), stearic acid (SA) (25.76?±?3.29 vs. 9.05%?±?2.53, P?<?0.001), and linoleic acid (LA) (5.25?±?1.18 vs. 0.5%?±?0.09, P?<?0.001) levels in individuals carrying the PGHS-2 306CC genotype when compared to GG genotype individuals. Subjects with the 8473CC genotype showed also a significant increase of PA, SA ,and LA levels when compared to TT genotype carriers (PA: 38.02?±?1.51 vs. 12.65%?±?1.54, P?<?0.001; SA: 32.96?±?1.87 vs. 1.38%?±?0.56, P?<?0.001; LA: 26.84?±?2.09 vs. 3.7%?±?1.54, P?<?0.001). Logistic regression analysis revealed that PGHS-2 306CC and 8473CC variants are significantly associated with obesity status (OR 6.25, CI (1.8–21.6), P?=?0.004; OR 3.01, CI (1.13–8.52), P?=?0.03, respectively). Haplotypes containing the C₃₀₆:T₈₄₇₃ (OR 2.91; P?=?0.01) and G_306:C₈₄₇₃ (OR 5.25; P?=?0.002) combinations were associated with an enhanced risk for obesity development in the studied population. In conclusion, our results highlight that PGHS-2 306G/C and 8473T/C variants could be useful indicators of obesity development, inflammation, and microvascular dysfunction among Tunisians.

     

Impact of nutritional conditions on yields,germination rate and shelf-life of Plectosporium alismatis conidia and chlamydospores as potential candidates for the development of a mycoherbicide of weeds in rice crops

The effect of nutritional conditions on spore qualities was investigated in order to select which propagules, conidia or chlamydospores, would be most suitable for mycoherbicide development. Plectosporium alismatis was grown in a liquid basal medium supplemented with glucose and a mineral nitrogen source (sodium nitrate) or an organic nitrogen source (casamino acids). Conidial and chlamydospore yields, germination rate and shelf-life were compared. Two growth models were developed: on one hand, sodium nitrate added as the sole nitrogen source was partially utilised (8%), resulting in poor growth (1.77±0.02 mg mL^?1; 6±1.7×10⁵ conidia mL^?1). Under these conditions, P. alismatis produced dense, melanised-like aggregates that contained chlamydospores (12.4±0.7×10⁴ chlamydospores mL^?1). Germination rates of chlamydospores and conidia produced under these conditions was high (80%). Twenty percent of chlamydospores were able to germinate after 4 months storage at 25°C, while survival of conidia declined rapidly (<2%). When casamino acids were added to the liquid medium as the sole nitrogen source, P. alismatis produced sparser pellets resulting in high dry weights (5.37±0.09 mg mL^?1 and high conidia numbers (9.6±1.5×10⁶ conidia mL^?1), while no chlamydospore were observed. The germination rate of conidia produced in casamino acids was low (33±13%) after 8 h incubation and microcycle conidiation occurred. Five percent of these conidia germinated after 4 months storage. These data indicate that chlamydospores may be suitable for mycoherbicide development, provided further optimisation of yields is achieved.     

Development of pilot-scale fermentation and stabilisation processes for the production of microsclerotia of the entomopathogenic fungus Metarhizium brunneum strain F52

Using 100 L stirred-tank bioreactors, we evaluated the effect of fermentation parameters and drying protocols on the production and stabilisation of microsclerotia (MS) of the entomopathogenic fungus Metarhizium brunneum (formerly M. anisopliae F52). Results showed that stirred-tank bioreactors can be used to mass produce stable MS of Metarhizium and that culturing and drying protocols significantly affected MS yield and stability. Length of fermentation (4–7 days) for Metarhizium cultures had no significant impact on biomass accumulation, MS formation or the storage stability of the air-dried MS granules. Although cultures of Metarhizium grown on media with a carbon-to-nitrogen (C:N) ratio of 30:1 produced significantly more biomass when compared to cultures grown in media with a C:N ratio of 50:1, MS formation and desiccation tolerance following drying were similar. After storage for 1 year at 4°C, conidia production by air-dried MS granules from 50:1 media was significantly higher compared to MS granules from 30:1 media. The addition of diatomaceous earth (DE) to cultures of Metarhizium prior to drying at rates of 0–60 g L^?1 had no significant effect on MS desiccation tolerance but did impact conidia production. Air-dried MS granules without DE produced significantly more conidia g^?1 during the first 4 months of storage, but after 1 year, conidia production was similar regardless of DE content of the MS granule. Microsclerotial granules with higher moisture levels (2.6–5.0% w/w) produced significantly more conidia immediately after drying and MS granules with low moisture (0–2.5% w/w) produced more conidia after 12 months storage.     

Ovostatin,an endogenous trypsin inhibitor of sea urchin eggs: Purification and characterization of ovostatin from eggs of the sea urchin,Strongylocentrotus intermedius

A trypsin inhibitor, termed ovostatin, has been purified approximately 265-fold with 82% yield, from unfertilized eggs of the sea urchin Strongylocentrotus intermedius, using trypsin coupled Sepharose 4B as an affinity column for chromatography. The isolated ovostatin is homogeneous in sodium dodecyl sulfate/polyacrylamide gel electrophoresis, the estimated molecular weight being 20K–21.5K. Ovostatin inhibits preferentially trypsin-like endogenous protease purified from the eggs of the same species and bovine pancreatic trypsin and also bovine pancreatic chymotrypsin. Values of IC₅₀ (amount causing 50% inhibition of enzymes) for trypsin-like protease purified from eggs of the same species, bovine pancreatic trypsin, and bovine pancreatic chymotrypsin, are 0.91 ± 0.13 μg/ml (4.55 ± 0.65 × 10^?8 M), 3.0 ± 0.28 μg/ml (1.5 ± 0.14 × 10^?7 M), and 4.8 ± 0.2 μg/ml (2.4 ± 0.1 × 10^?7 M), respectively, in the experimental condition used. Kinetic studies indicate that ovostatin is a noncompetitive inhibitor of trypsin. The inhibitor is relatively heat labile. NaCl (0.025–0.01 M) enhances the inhibitor activity, whereas KCl is inhibitory. Ovostatin requires a low concentration of Ca²⁺ for activity. The activity is higher in unfertilized eggs than in fertilized eggs; total activity and specific activity in unfertilized eggs is about 1.67-fold and 1.85-fold higher than those in fertilized eggs, respectively. We believe that ovostatin may regulate the function of the cortical granule protease and other trypsin-like proteases that are activated in sea urchin eggs during fertilization.     

Production of microsclerotia by Brazilian strains of Metarhizium spp. using submerged liquid culture fermentation

We investigated the potential production and desiccation tolerance of microsclerotia (MS) by Brazilian strains of Metarhizium anisopliae (Ma), M. acridum (Mc) and M. robertsii (Mr). These fungi were grown in a liquid medium containing 16 g carbon l^?1 with a carbon:nitrogen ratio of 50:1. One hundred milliliters cultures were grown in 250 ml Erlenmeyer flasks in a rotary incubator shaker at 28 °C and 200 rpm for 5 days. Five-day-old MS were harvested, mixed with diatomaceous earth (DE) and air-dried for 2 days at 30 °C. The air-dried MS–DE granular preparations were milled by mortar + pestle and stored in centrifuged tubes at either 26 or ?20 °C. Desiccation tolerance and conidia production were assessed for dried MS granules by measuring hyphal germination after incubation for 2 days on water agar plates at 26 °C and for conidia production following 7 days incubation. Yields of MS by all strains of Metarhizium were 6.1–7.3 × 10⁶ l^?1 after 3 days growth with maximum MS yields (0.7–1.1 × 10⁷ l^?1) after 5 days growth. No differences in biomass accumulation were observed after 3 days growth, whereas Ma-CG168 showed the highest biomass accumulation after 5 days growth. Dried MS–DE preparations of all fungal strains were equally tolerant to desiccation (≥93 % germination) and the highest conidia production was obtained by MS granules of Mc-CG423 (4 × 10⁹ conidia g^?1). All MS granules showed similar stability after storage at either 26 or ?20 °C for 3.5 months.     

Evaluation of the pathogenicity of Aschersonia aleyrodis on Bemisia tabaci in the laboratory and greenhouse

The entomopathogenic fungus Aschersonia aleyrodis (Webber) is a promising fungal species against whiteflies. In this work, the pathogenicity of A. aleyrodis isolate Aa005 against MEAM1 Bemisia tabaci (Gennadius) was evaluated under laboratory and greenhouse conditions. The bioassay results indicated that the percentage of larval mortalities was concentration and age dependent. A. aleyrodis showed high pathogenicity against second and third instars and pupae with LC₅₀ values of 7.93?×?10⁶, 1.08?×?10⁷, and 1.56?×?10^7?conidia?mL^?1, respectively. The median lethal time (LT₅₀) was lower (4.60 days) for second instars and was the highest (6.17 days) for pupae when inoculated with a concentration of 1?×?10^7?conidia?mL^?1. Weekly sampling of immatures showed that the per cent mortality caused by A. aleyrodis at a conidial concentration of 1?×?10^7?conidia?mL^?1 was 71.21% in small nymphs, 69.31% in large nymphs and 53.36% in pupae. The dispersion index (DI) and Lloyd’s Index of Patchiness (LIP) values indicated that the infected immatures had a tendency to aggregate. The study demonstrated that A. aleyrodis isolate A005 is an effective biocontrol agent for B. tabaci control under laboratory and greenhouse conditions.     

Effects of traditional insecticides on Habrobracon hebetor (Hymenoptera: Braconidae): bioassay and life-table assays

The lethal and sublethal effects of the insecticides chlorpyriphos and fenpropathrine, which are overused in tomato production, were evaluated on the larval, pupal and adult stages of the parasitoid Habrobracon hebetor in the laboratory. Dose-response bioassays were carried out on immature and adult stages by using dipping and contact residue methods, respectively. The LC₅₀ of chlorpyriphos varied from 40 to 2000 times less than the recommended field rate and 10–100 times less for fenpropathrine treatments on the different life-history stages. To assess the sublethal effects, all life-history stages were exposed to LC₂₅ equivalent concentration of each insecticide and the demographic parameters of surviving parasitoids were studied. In LC₂₅ tests on adult stage, mean longevity and fecundity showed significant differences between chlorpyriphos (15.93?±?1.37 d and 128.20?±?20.20 eggs) and fenpropathrine (12.76?±?0.78 d and 124.00?±?12.27 eggs) as compared with the control (20.41?±?0.72 d and 281.00?±?12.95 eggs). In addition, net reproductive rate and intrinsic rate of increase indicated significant differences between chlorpyriphos (22.89?±?6.43 and 0.19?±?0.02) and fenpropathrine (14.44?±?3.58 and 0.17?±?0.02) as compared with the control (55.55?±?12.54 and 0.24?±?0.02). Briefly, we can conclude that both insecticides had negative effects on H. hebetor. However, the negative effect of fenpropathrine on r_m was higher than that of chlorpyriphos. In conclusion, field studies are recommended to determine the total effects of these insecticides on H. hebetor.     

The mixture of kresoxim‐methyl and boscalid,an excellent alternative controlling grey mould caused by Botrytis cinerea

Grey mould, caused by the fungus Botrytis cinerea, is one of the most destructive diseases in greenhouses for which serious fungicide resistance has developed. Between 2003 and 2005, 213 isolates of B. cinerea from two geographical regions were characterised for baseline sensitivity to kresoxim‐methyl. In the absence of salicylhydroxamic acid (SHAM), the mean 50% effective concentration (EC₅₀) values were 6.67 ± 0.61 (mean ± SD) and 0.37 ± 0.10 mg L^?1 during growth and germination, respectively. In the presence of 100 mg L^?1 SHAM, baseline sensitivities were distributed as unimodal curves with mean EC₅₀ values of 2.38 ± 0.21 and 0.28 ± 0.09 mg L^?1 for inhibiting growth and inhibiting germination, respectively. The mixture of kresoxim‐methyl and boscalid showed good control efficacy against strawberry grey mould disease. After the mixture was extensively used on strawberry for 2 years, 50 isolates were collected and determined for their sensitivity to kresoxim‐methyl and boscalid, respectively. The mean EC₅₀ of germination inhibition by boscalid was 0.39 ± 0.08 mg L^?1. The mean EC₅₀ of germination inhibition by kresoxim‐methyl was 0.26 ± 0.07 mg L^?1 in the presence of 100 mg L^?1 SHAM. Sensitivities of B. cinerea to both kresoxim‐methyl and boscalid did not show any significant decrease. These results suggest that their mixture is a satisfactory alternative candidate for management of grey mould disease in greenhouses.     

The potential of Beauveria bassiana inoculum formulated into a polymeric matrix for a microbial control of spruce bark beetle

Two local strains of Beauveria bassiana originally isolated from naturally infected spruce bark beetles in Slovakia were tested for their virulence to Ips typographus (IT) and for their compatibility with a polymeric matrix composed of low-molecular polyethylene. Conidia could be homogenously immobilized in the low-molecular polyethylene matrix with no adverse effect on their viability and infectivity. At constant temperature (25°C), viability of immobilized conidial decreased only by 1–2% after 7 or 14 days when compared with non-formulated conidia. In field conditions, viability of conidia formulated in the matrix was even significantly higher than non-formulated conidia 35 days after their application in traps. Conidia incorporated into the polymeric matrix were infective to IT adults in laboratory bioassays. Mean values of LC₅₀ for native conidia (0.72–2.05?×?10⁶ conidia?ml^?1) and conidia immobilized in the polymeric matrix (0.64–1.03?×?10⁵ conidia?mm^?2) demonstrated high virulence. The efficacy of the local strains was significantly higher than that of B. bassiana strains from mycoinsecticides (Boverol^®, Botanigard^® ES and Naturalis-L^®). Results showed potential of this polymeric material for its use in microbial control of IT when mixed with conidia of B. bassiana.     

Inhibition of two enzyme systems in Euchlanis dilatata (Rotifera: Monogononta) as biomarker of effect of metals and pesticides

The inhibitory effects on esterases and phospholipase A2 (PLA2) in the freshwater rotifer Euchlanis dilatata, native to Mexico, were assessed by fluorimetry after in vivo exposure (30?min) in laboratory conditions to sublethal concentrations of metals and pesticides. EC₅₀ values for esterases ranged from 7.9?×?10^?7 for DDT to 61.9 μg l^?1 for methyl parathion, while corresponding values for PLA2 ranged from 0.96?×?10^?6 for mercury to 69.2 μg l^?1 for lead. These enzyme systems in E. dilatata are very sensitive to the tested agents and suggest they would be suitable biomarkers. However, sensitivity to other environmental contaminants should be investigated in laboratory conditions and field studies to assess their potential as environmental biomarkers.     

Toxicity of 2,3,5,6-tetrachlorophenol to willow trees (Salix viminalis)

Chlorinated phenols have been intensively investigated from an eco-toxicological point of view, however almost nothing is known about toxicity of tetrachlorophenol (TeCP) to higher terrestrial plants. This article applied the willow tree acute toxicity test to study the toxicity of 2,3,5,6-TeCP to willows Salix viminalis (S. viminalis) at neutral and acidic conditions (roughly pH 7 and 4) with inhibition of transpiration as toxic endpoint. At neutral pH the EC₅₀ was >10 mg L^?1 while the EC₅₀ at acidic conditions was 0.32 ± 0.17 mg L^?1, clearly indicating that toxicity is exerted by the non-ionic chemical fraction. Standard tests running at neutral pH are therefore not capturing the full toxicity of weak acids and bases.     

Effect of treating eggs of cotton bollworm with Bacillus thuringiensis Berliner on functional response of Trichogramma brassicae Bezdenko

Cotton bollworm, Helicoverpa armigera (Hübner) is a cosmopolite insect pest of a wide spectrum of crops such as cotton, maize, tomato, soybean, etc. Egg parasitoids mainly Trichogramma brassicae Bezdenko and Bacillus thuringiensis Berliner (Bt) are biological control agents, that are used as components of sustainable and environmentally compatible IPM systems. Although Bt does not come in direct contact with egg parasitoids, it may persist within the host’s body and affect the quality of the host’s eggs via biochemical changes in their mother and possibly behaviour and potency of the parasitoids. In this study, the functional response of T. brassicae to different densities of H. armigera eggs was investigated in two sets of experiments at 26?±?1?°C, 65?±?5% RH, and 16: 8?h photoperiod. The first group was a control and the second one were eggs laid by hosts treated as 3rd instar larvae with LC₂₀ of Bt (determined as 9.8?×?10^5?IU/l of artificial diet based on a preliminary bioassay). A type III functional response was observed in both treatments with a direct density dependent mortality up to eight host eggs and an inverse one upward. Both handling time and searching efficiency were affected by Bt treatment as the handling time was increased by a factor of 1.5 and the searching efficiency was decreased by a factor of 0.6. The searching efficiencies were 0.0310?±?0.003 and 0.0182?±?0.005?h^?1, and handling times were 1.134?±?0.042 and 1.672?±?0.082?h in control and Bt treatment respectively.     

Life table of Gaeolaelaps aculeifer (Acari: Laelapidae) feeding on larvae of Lycoriella auripila (Diptera: Sciaridae) with stage-specific estimates of consumption

Gaeolaelaps aculeifer (Canestrini, 1883) is a soil-dwelling predatory mite with potential for use as a biological control agent of fungus gnats (Diptera: Sciaridae) in mushroom production. The life table, predation rate and population growth rate of G. aculeifer on a diet of larvae of the sciarid fly, Lycoriella auripila, at 23?±?1°C, 60?±?5% RH and a photoperiod of 0:24 (L:D)?h was investigated. The results revealed that the duration of egg, larva, protonymph, deutonymph, females and males of G. aculeifer were 3.8?±?0.1, 1.4?±?0.1, 3.9?±?0.1, 4.1?±?0.1, 67.7?±?2.8 and 60.3?±?3.1 days, respectively. Net reproductive rate (R₀) was 54.8?±?7.1 offspring, intrinsic rate of increase (r) was 0.12?±?0.01 offspring day^?1, finite rate of increase (λ) was 1.13?±?0.01 day^?1and mean generation time (T) was 32.3?±?0.6 days. The predator consumed a mean of 0.08?±?0.05, 1.73?±?0.18, 3.16?±?0.28 and 75.9?±?7.1 third instar L. auripila larvae during the larval (1.3?±?0.1 days), protonymph (3.9?±?0.1 days), deutonymph (4.1?±?0.1 days) and adult (52.6?±?2.2 days) stages. Population parameters and consumption rates suggest that G. aculeifer has good potential as a biological control agent of L. auripila in mushroom production.