Diatomaceous Research Articles

Characterization of lime based insulating mortars for existing buildings in the EU market

There are several lime mortars which have been developed to improve the thermal performance of the facades of existing buildings. They are used as the final coating of a building’s facade thanks to their insulating capacities, weather resistance, vapour permeability, easy application, non-flat substrates adaptability, and/or masonry compatibility. Normally these mortars come into a system to achieve both thermal properties and weathering resistance. The thermally improved mortars, which are lime based, contain an important amount of insulating particles such as cork, diatomaceous earth, expanded clay, expanded perlite or vermiculite, mullite, aerated glass, aerogel, EPS, wood fibres or others. They also may contain pozzolanas and other cementitious particles. They also may contain additives in order to improve its mechanical resistances and/or elasticity. The weathering resistance mortar, the more external one, is suited to complete the mechanical and outdoor resistance properties that the insulated layer lacks. Some of these systems may be obliged to use glass fibre meshes and External Thermal Insulation Composite Systems (ETICS) anchors so they are not as suitable as wanted in historical buildings. In this abstract our main goals are: Acknowledge the reasons to use these mortars, define the multiple layer system that are normally used within these mortars, find which mortars are normally available to be bought in the European Union market, analyse their declared properties and composition, and enlist them according to their potential capacities. Thanks to this paper we will have a better knowledge of the possibilities of lime mortars as insulating material.

Exploring diatomite as a novel natural resource for ecofriendly-sustainable hybrid cements

The primary goals of the present study are to decrease CO2 emissions and minimize the excessive consumption of natural resources associated with cement production. The main natural resource was diatomite (DIO), a naturally abundant material found in several regions of Mexico. Four different hybrid cement (HC) mixtures were prepared using NaOH, while maintaining a consistent OPC percentage of 10 % across all the mixtures. The obtained results demonstrate the exceptional performance of one of these HC mixtures, surpassing OPC properties in terms of compressive strength at 1, 7 and 28 days, with values of 28.8, 47.16 and 62.9 MPa, respectively. The outstanding HC mixture underwent thorough confirmation through a range of analyses, such as TG, FTIR, SEM and EDX. This innovative HC composite offers several solutions to reduce CO2 emissions and conserve natural resources currently wasted in cement manufacturing, making it a compelling choice for various industrial and construction applications.

Effect of the Pătârlagele Diatomite on Seed Germination and Growth of Sunflower Plants

Sunflower (Helianthus annuus L.) is the third largest agricultural crop in Romania, after corn and wheat. In 2021 Romania cultivated 1112 thousand ha of sunflower with a production of 2818 thousand tons, ranking first among EU countries both in terms of production and cultivated area. Diatomite, also called diatomaceous earth or kieselguhr, is a natural sedimentary rock with a high content of silicon dioxide and clay minerals, widely used in agriculture for its insecticidal and fungicidal properties, stimulating the process of seed germination and plant growth, as well as the ability to absorb and retain nutrients and water. The paper presents preliminary results regarding the effect of diatomite from Pătârlagele deposit (Buzău County) on seed germination and growth of young sunflower plants in laboratory conditions and on seeds production in the field at three sowing dates as well. A semi-early hybrid P64LE99 was used in experiments. Our data showed that the Pătârlagele diatomite improves sunflower seed performances both in laboratory and field conditions. In the laboratory, an increase in seed germination and stimulation of plant growth and development were observed in the diatomite treated samples compared to the untreated control. In the field under climatic and soil conditions of the Moara Domnească area (Southern Romania), the diatomite treated samples performed better than the control, both in terms of plant growth and development as well as production elements, in three sowing dates, middle and late April and early May. The highest yields were when sowing was in the first week of May for both variants.

Učinkovitost šest hrvatskih inertnih prašiva i dijatomejske zemlje Celatom Mn-51® u suzbijanju kestenjastog brašnara Tribolium castaneum Herbst (Coleoptera: Tenebrionidae) na pšenici

The study investigated the insecticidal efficacy of six Croatian inert dusts (D-01, JU-1, MA-4, MR-10, OP-4 and PD-1) and diatomaceous earth Celatom Mn-51® against red flour beetle Tribolium castaneum Herbst on wheat. The influence of mentioned dusts on the offspring development has also been investigated. The experiment was carried out in laboratory conditions on insects aged 7-21 days. Doses of 600 and 700 mg were tested for JU-1, MR-10, OP-4 and PD-1 and 300 and 400 mg for D-01, MA-4 and Celatom Mn-51® alongside previously mentioned doses (600 and 700 mg ). The mortality rate of red flour beetle was determined on the 7th and 14th day of exposure and progeny was determined by number of developed adults. Regarding the insecticidal efficacy on T. castaneum the tested inert dusts can be divided into three groups: very effective dusts (D-01 ( = 600 mg ), MA-4 ( = 500 mg ), medium-effective dusts (JU-1 and PD-1) and low-efficient dusts (OP-4 and MR-10). Based on the obtained results it can be concluded that there are some resources of inert dusts with high insecticidal potential in the Republic of Croatia.

Effect of diatomaceous earth on diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae), larval feeding and survival on cabbage

Effect of diatomaceous earth on diamondback moth, <i>Plutella xylostella</i> (Lepidoptera: Plutellidae), larval feeding and survival on cabbage

Usage of human diatomaceous earth

Diatomaceous earth is naturally formed sedimentary mineral rock resulting from the remains of diatoms, or oceanic unicellular algae. It is extracted from diatoms mined from deposits of diatomite and manufactured into a powder that is diatomaceous earth for human use, as a natural compound. It is gaining popularity as having an outstanding list of health benefits and non-toxic, no-known side effect origins. In this paper, a comprehensive review is presented to highlight the availability, benefits, mechanism of operation, and effects on the use of Human Diatomaceous Earth. The review revealed that diatomaceous earth has an outstanding list of health benefits and non-toxic, no-known side effects. It has the ability to lower the concentration of cholesterol in the blood. It is a very essential mineral for tendons, cartilage, blood vessels, and bones. Diatomaceous Earth is also considered to greatly help the body in getting rid of toxic substances such as heavy metals. It improves body joints bones, and ligaments through silica, which is the highest-occurring compound in diatomaceous earth that aids in the metabolism and formation of the joints.

Insecticidal Effect of a Natural Turkish Diatomaceous Earth Formulation on Greater Wax Moth

In this study, the insecticidal effect of the Detech® (Turkish Diatomaceous earth) DE formulation against Galleria mellonella L. was determined. The study was conducted in a laboratory environment with materials taken from beehives produced at Muş Alparslan University in 2022. Diatomaceous earth (DE) was applied in two different forms (dust and slurry DE) and as positive control GüveSavar®, which is currently used against some pests in beekeeping. DE concentrations of 0, 3, 5, and 7 g/m2 in different exposure times were tested for the control of G. mellonella larvae. As a result of all treatments, the highest mortality occurred at 7 g/m2 dust DE concentration. Larvae (3rd stage) exposed to 7 g/m2 concentration according to dust DE mortality rates reached 100% mortality after 40 hours. According to the results of the slurry DE, the larvae exposed to the slurry diatom at all concentrations achieved 100% mortality at the end of the 96 hours. When the dust and slurry DE results were examined, the direct use of dust formulations greatly accelerated the effectiveness against larvae. The study showed very promising results, suggesting that slurry DE and dust formulations could be a new alternative control method for Greater Wax Moth. In addition, for the first time, the insecticidal efficacy of DE against the honey bee pest, the greater wax moth, was determined.

Dolomitic Limestone Powder: Cement Substitute in the Production of Structural Concrete Paving Blocks

Manufacturers are replacing or combining cement with mineral additives such as slags, natural pozzolans, sand, diatomaceous earth and limestone to reduce carbon dioxide emissions and energy usage. Due to its high magnesium content, dolomitic limestone has long been utilized in concrete production to reduce costs and environmental risks associated with making cement. This study aimed to produce a reliable and appropriate concrete mixture for concrete paving blocks using dolomitic limestone powder that passed the no. 24 sieve as cement replacement at replacement levels of 0 (control mix), 8, 12, 16, 20, 24, 28 and 32%, satisfying the minimum compressive strength requirement for structural concrete of 20.7 MPa (3,000 psi). The ASTM E877-13 was used to sample the dolomitic limestone, and the 1:1.5:3 concrete class combination was utilized to proportion the quantities of cement, sand and aggregates (3/8”). After 28 days, the specimens were cured and the compressive strength, through the varying water-cement ratios in the concrete mixture, was determined. Results showed that dolomitic limestone powder can substitute cement by 16% by weight, using a concrete mix of 523-g cement, 936-g sand, 1,868-g gravel, 100-g dolomitic limestone powder, and 166-g water with a water-cement ratio of 0.318, exceeding the minimum necessary compressive strength of concrete of 20.7 MPa by 24.9% or 5.16 MPa. Therefore, it is advised to utilize this proven concrete mixture as a basis for a potential business venture in the production of concrete paving blocks for structural concrete applications such as walkways, sidewalks, parking lots and commercial areas, as well as in places where loads are very high, like airports, courtyards, docks and freight yards.

Sustainable SiO2 Nanostructures from Different Diatom Species As Anode Material for Future Generation Lithium-Ion Batteries

Energy harvesting and storage devices occupy a more prominent place in the 21st century than at any time in the past. Intensive efforts have been devoted to next-generation energy storage devices such as rechargeable lithium-ion batteries (LIBs) to develop high energy density and long cycle life electrode materials from sustainable sources. In the present anode, graphite is severely restricted by capacity and unavoidable solid electrolyte interface (SEI) formation. Besides, it has been listed as a critical material by the European Commission. Recently, silicon-based electrodes have been pinpointed as promising anode candidates due to their high theoretical capacity (~4200 mAhg-1 for Li4.4Si), low operating voltage (0.4V/Li/Li+), abundant resources, and environmental friendliness. Interestingly, nanostructures of Silica (SiO2) can be extracted from the frustules (exoskeletons) of a type of microalgae called diatoms. In this current work, SiO2 frustules were grown from two different diatom species, constituting a sustainable source for producing nanostructured Si-based materials. Scanning electron microscopy (SEM) images confirmed the highly nanoporous structure of diatom silica, which was retained even after ball-milling. The electrochemical performance of SiO2 was investigated as an anode material for LIBs. Herein, we have tested both species A & B milled and un-milled samples (denoted as SPAUM, SPAM, SPBUM, and SPBM). The diatom SiO2 un-milled species A (SPAUM) exhibited a high specific capacity of ~ 810 mAhg-1 with remarkable capacity retention and coulombic efficiency even after 100 cycles at 0.1 Ag-1 and delivered a high specific capacity of ~ 400 mAhg-1 even at high current density 3 Ag-1. For comparison and understanding, commercially available diatomaceous earth milled, and un-milled silica (denoted as EDAM & EDAUM) has been subjected to the same cycling protocol. Results clearly showed species A & B milled and un-milled displaying better electrochemical performance than diatomaceous earth milled and un-milled silica. Such improved electrochemical properties like cycle life, and rate capability of SPAUM are mainly ascribed to their highly porous nature which significantly facilitates fast Li ion diffusion, its unique morphology, which favors a faster kinetics and its complete lithiation/de-lithiation after the initial activation cycle. In view of the superior electrochemical properties, such sustainably sourced SiO2 materials can be considered a potential anode material for future LIBs. Figure 1

Enhancement of hydrophobicity in natural rubber vulcanizates using diatomaceous earth

This study discusses an approach that gives the Natural Rubber (NR) vulcanizates an elevated hydrophobic character. The method used a chemically treated filler called diatomaceous earth (DE) to deliver the hydrophobic characteristics to NR. DE has a nanoscale roughness. It was chemically treated with hexadecyltrimethoxy silane to obtain low surface energy. The combination of nanoscale roughness and low surface energy gave superhydrophobic properties to DE. A series of treated-DE was made with varying silane percentages to find an optimum silane to DE ratio to get the maximum possible hydrophobicity. The optimum ratio was recorded as 38% w/w, and the treated DE displayed a superhydrophobic water contact angle (WCA) of 152°. The treated-DE was added to the rubber as a filler during the compounding process. The filler was added in varying amounts of 5 phr, 10 phr, 15 phr, and 20 phr to observe the changes in the hydrophobic property. The wettability and morphology of developed vulcanizates were measured using WCA measurements and scanning electron microscope (SEM) analysis, respectively. NR compounded with 20 phr filler exhibited an enhanced WCA of 136°, compared to the WCA of 92° of the NR vulcanizate with no treated-DE, and displayed improved tensile, and tear properties.

Оценка на зеолит и диатомит за оптимизиране на хранителния режим при два типа почви

The research investigates the effectiveness of natural zeolites, diatomaceous earth and compost mixture as self-effects and their combinations on the NPK potential of two soil types. In both soils, the following variants were investigated: soil-compost (SC), soil-zeolite (SZ) and soil-diatomite (SD); as well as combined variants such as soil-compost-zeolite (SCZ) and soil-compost-diatomite (SCD). These components are composted over 60 days under controlled conditions. To achieve this goal, basic physicochemical parameters such as pH and electrical conductivity, cation exchange capacity (CEC), and agrochemical indicators – humus and mineral forms of nitrogen, phosphorus and potassium – before and after composting were traced. The study shows that combining natural zeolites and diatomaceous earth sludge with compost contributes to increasing potassium and phosphorus levels in the soil while maintaining the stability of soil organic matter, highlighting the most effective impact on phosphorus under certain pH conditions.

Efficacy of Four Insecticides Applied to Fortified Rice with Basil against Major Stored-Product Insect Species

Rice is one of the most important foods since it is grown in many countries and consumed by the majority of the population. Ensuring food security through the protection of stored-product commodities has become one of the most important priorities worldwide. In this study, the effects of three insecticidal formulations and an available diatomaceous earth formulation on basil-fortified rice against the major stored-product insects were evaluated. The label dose of each insecticidal formulation was used. Insect mortality was determined after 1, 3, 7, 14 and 21 days for each species. The entire experiment was repeated three times by preparing different lots of treated and untreated rice for each treatment. The results of the diatomaceous earth treatments showed that the most susceptible individuals were Sitophilus oryzae adults and Oryzaephilus surinamensis larvae, while the least susceptible individuals were Rhyzopertha dominica and Tribolium castaneum adults. The tested insecticides were effective against S. oryzae, as mortality was 100%. Between the two pyrethroids, deltamethrin was more effective than cypermethrin in the tested insecticides. Our findings indicate that there are available insecticides on the market which can be obtained successfully for the durable protection of agricultural commodities after the harvest stage.

Experimental analysis of Algerian diatomaceous earth aimed at silicon extraction

Silicon, primarily derived from silica, plays a crucial role in creating glass, ceramics, and heat-resistant materials, making it indispensable across various industrial sectors. Moreover, it is fundamental in the manufacturing of semiconductors and electronic components. The main goal of our project is to study diatomite, particularly from Algerian deposits, such as western diatomite in order to extract silicon to achieve this, we will conduct experiments using electron microscopy and X-Ray Diffraction (XRD). These analyses highlight the significance of chemical methods in silicon extraction. Our focus is primarily on improving our study by examining the impact of various parameters, notably the use of acid cleansings, on the final product. These parameters are chosen based on the complex chemical reactions governing the aggregation of silica particles in the solution.

Extraction of silica from natural deposits for the production of silicon in photovoltaic applications

The Silica, primarily sourced from silicon dioxide (SiO2) is a common chemical compound abundant in nature, existing in various forms such as quartz, sand, glass, and diverse minerals. It finds extensive use across multiple industries, contributing significantly to glassmaking, ceramics, abrasives, refractory materials, and serving as a crucial component in semiconductor production for electronic chips. This work provides a comprehensive review of the silica elaboration process aimed at obtaining silicon. The initial stage involves the preparation of raw materials, utilizing Algerian sand and diatomite, which undergo meticulous chemical treatment to eliminate unwanted impurities. This method comprises distinct steps, known as the purification process, wherein the sand or diatomite shell is assessed through dissolution in a caustic alkaline solution. This approach indicates the potential to generate high-quality silica from diatomite using an aqueous chemical process. This paper explores the prospect of sand or diatomaceous earth as a novel source of premium-grade silica. It discusses the effects of hydrochloric acid as a solvent for purification. This study contrasts treatment methods before and after acid leaching, focusing on samples with larger particle sizes (ranging from 53 to 300 microns), shorter refining durations (1 to 6 hours), and relatively higher temperatures (30 °C to 70 °C). The findings reveal that the highest purity of silica was attained through HCl treatment (25%).

Insight into modified Ce[sbnd]Mn based catalysts for efficient degradation of toluene by in situ infrared

Trace activated carbon (AC) and diatomaceous earth (DE) were used as structural promoters to be incorporated into Ce-Mn-based solid-solution catalysts by the redox precipitation method. The modified catalysts exhibit superior reducibility, with abundant Ce3+, Mn3+and reactive oxygen species, which are facilitated to the migration of oxygen and the generation of oxygen vacancies. In particular, the catalytic combustion temperatures of 90 % toluene (3000 ppm) on Ce1Mn3Ox-AC/DE were 84 °C (dry) and 123 °C (10 vol% H2O), respectively. The role of lattice oxygen and adsorbed oxygen was revealed by in situ DRIFTS. Additionally, in situ DRIFTS was employed to verify that the degradation of toluene by Ce1Mn3Ox-AC/DE satisfied the Langmuir-Hinshelwood (L-H) mechanism and the Mars-Van Krevelen (MvK) mechanism. The possible reaction pathway was elucidated (toluene → benzyl alcohol → benzoic acid → maleic anhydride → CO2 + H2O). Furthermore, final products attributed to toluene oxidation were detected by in situ DRIFTS at 50 °C in the absence of oxygen, confirming that the catalyst possessed outstanding performance at low temperatures beyond mere adsorption.

The dam that fly ash built.

When the first concrete was poured in 1949 for the Hungry Horse Dam (Montana, USA), pozzolan cements had already been used in several major North American dams, including Grand Coulee on the Columbia River (diatomaceous earth explored but ultimately not used), Friant on the San Joaquin River and Altus on the North Fork Red River (pumicite) and Bonneville on the Columbia River and Davis on the Colorado River (calcined clay). But Hungry Horse Dam stands out as the first dam constructed using coal combustion fly ash. Utilising 2.4 million cubic metres of concrete, the dam is located on the South Fork Flathead River, one of the tributaries feeding one of the nation's major waterways, the Columbia River, and closely related to the adjacent Glacier National Park. In this respect, Hungry Horse is directly connected to two momentous periods in modern history - the massive adoption in the 1950s of coal as fuel for power plants, and the ongoing threats to fresh water supply and the rapid retreat of alpine glaciers due to global warming. Two concrete cores from this dam, one with fly ash and one without fly ash, are examined microscopically to explore the long-term suppression of alkali-aggregate reaction by fly ash. The core without fly ash exhibits clear evidence of alkali-aggregate reaction, manifested by sandstone coarse aggregate particles with darkened reaction rims. Sandstone coarse aggregate particles of the same lithology in the core with fly ash are without signs of alkali-aggregate reaction. A detailed examination of the darkened rims indicates that alkali-silica reaction products fill the narrow gaps between adjacent sand grains in the sandstone. This alkali-silica gel infilling allows for optical continuity between adjacent sand grains and is responsible for the classic darkened rim associated with the alkali-aggregate reaction.

Robust performance for composites using silicone rubber with different prospects for wearable electronics

AbstractThe different configurations of the composites originated with machine or human motion, and their mechanical stability for wearable electronics is in focus. Here, the study highlights that these configurations are critical for wearable devices. To achieve these aspects, the electroactive and dielectric silicone rubber (SR) was used as a host matrix. This SR not only provides flexibility, twisting, or stretchability for such devices, but its lightweight makes them comfortable for robust wearable devices. The reinforcing fillers such as graphite nanoplatelets (GNP) or diatomaceous earth (DE) and their hybrids are used. The electromechanical properties of the device were performed using the universal testing machine. The output voltage generated at 15 phr filler was 0.3 mV (GNP), 0.15 mV (DE), and 0.22 mV (hybrid). Similarly, the biomechanical properties were studied with human motion joints such as thumb pressing or wrist bending. The output voltage at 15 phr was best for thumb pressing and it was 0.42 mV (GNP), 0.18 mV (DE), and 0.25 mV (hybrid). In the same way, the mechanical aspects studied in this work are compressive modulus, tensile strength, and fracture strain. For example, the compressive modulus was 1.28 MPa (control) and increased at 15 phr filler to 2.44 MPa (GNP), 3.2 MPa (DE), and 2.75 MPa (hybrid). Similarly, the mechanical stretchability of the devices was 134% (control) and changed at 15 phr filler to 128% (GNP), 78% (DE), and 109% (hybrid). Overall, the work demonstrates the method to develop a device with high mechanical, electromechanical, and biomechanical properties and their usefulness for wearable electronic devices.

Modified Diatomaceous Earth in Heparin Recovery from Porcine Intestinal Mucosa.

Heparin, a highly sulfated glycosaminoglycan, is a naturally occurring anticoagulant that plays a vital role in various physiological processes. The remarkable structural complexity of heparin, consisting of repeating disaccharide units, makes it a crucial molecule for the development of commercial drugs in the pharmaceutical industry. Over the past few decades, significant progress has been made in the development of cost-effective adsorbents specifically designed for the adsorption of heparin from porcine intestinal mucosa. This advancement has been driven by the need for efficient and scalable methods to extract heparin from natural sources. In this study, we investigated the use of cationic ammonium-functionalized diatomaceous earth, featuring enhanced porosity, larger surface area, and higher thermal stability, to maximize the isolated heparin recovery. Our results showed that the higher cationic density and less bulky quaternary modified diatomaceous earth (QDADE) could adsorb up to 16.3 mg·g-1 (31%) of heparin from the real mucosa samples. Additionally, we explored the conditions of the adsorbent surface for recovery of the heparin molecule and optimized various factors, such as temperature and pH, to optimize the heparin uptake. This is the introductory account of the implementation of modified diatomaceous earth with quaternary amines for heparin capture.

Performance Characterisation and Microscopic Characteristics of Rapeseed Heavy Oil–Diatomaceous Earth Composite-Modified Asphalt

In order to further improve the performance of bio-asphalt, because of its poor high-temperature performance, another biomass material, diatomaceous earth, was employed as a composite modifier, and a composite-modified asphalt was made to increase the high-temperature performance of bio-asphalt. The optimal preparation parameters of a rapeseed heavy oil–diatomaceous earth composite-modified asphalt were identified by employing an orthogonal test design. Based on the laboratory test, the physical properties, rheological properties, and microscopic properties of the asphalt were evaluated correspondingly by utilising matrix asphalt, rapeseed heavy oil-modified asphalt, and diatomaceous earth-modified asphalt as the control group. The results of the orthogonal test analysis showed that the optimum preparation parameters of the rapeseed heavy oil–diatomaceous earth composite-modified asphalt were 8% rapeseed heavy oil, 5% diatomaceous earth, a shear period of 35 min, and a shear rate of 2500 r/min. The addition of rapeseed heavy oil improved the fatigue resistance and low-temperature performance of the asphalt, but, at the same time, the asphalt penetration increased, the softening point and viscosity decreased, and the high-temperature rutting resistance decreased. Compared with the matrix asphalt, the viscosity of the rapeseed heavy oil–diatomaceous earth composite-modified asphalt at 135 °C rose by 23.2%. The rutting factor G*/sinδ increased by 45.5%, 15.6%, 17.6%, 29.8%, and 22.0%, while the fatigue factor G*·sinδ increased by 41.9%, 14.2%, 16.7%, 19.4%, and 23.1%, respectively, in the high-temperature rheological properties test temperature interval from 52 °C to 76 °C. The creep stiffness S fell by 16.2%, 36.1%, and 25.2%, while the creep rate m rose by 25.8%, 52.9%, and 13.4%, respectively, in the low-temperature rheological performance test temperature interval from −24 °C to −12 °C. Therefore, diatomaceous earth may effectively counteract the softening effect of the rapeseed heavy oil on the matrix asphalt and may raise the strength level and permanent deformation resistance of the composite-modified asphalt with only partial loss of fatigue resistance. The matrix asphalt, rapeseed oil, and diatomaceous earth exhibited high compatibility. The integration of rapeseed oil and diatomaceous earth largely did not modify the chemical properties of asphalt, and it was able to maintain the qualities of asphalt itself. Rapeseed heavy oil and diatomaceous earth on the thermal stability of the matrix asphalt has the opposite effect. The reorganisation component of diatomaceous earth on the colloidal structure of asphalt is conducive to the stabilisation of the nature of the asphalt, which can significantly improve the temperature stability of asphalt.

Genotypic markers associated with cold storage survival of the entomopathogenic nematode Heterorhabditis bacteriophora

Summary Limited shelf life is a major constraint to successful commercialisation of entomopathogenic nematodes (EPN), and to extend shelf life, dauer juveniles (DJ) are formulated and stored at low temperatures (4-8°C). We evaluated the cold storage potential of strains of Heterorhabditis bacteriophora formulated in diatomaceous earth at storage temperatures between 5 and 9°C. When assessing DJ decline to reach 75% survival (MT75) in the formulation for the respective temperatures, H. bacteriophora strain HB4 had the highest survival of 25 days at 9°C, while strain D2D6 survived longest at 8°C for 28 days. A set of 22 H. bacteriophora wild type inbred lines was then phenotyped for cold tolerance in water under oxidative stress in 70 mM H2O2 at 2°C. The MT50 (time to 50% survival) ranged from 11 to 23 days. The phenotypic data were correlated with the respective genotypic data, identifying four single nucleotide polymorphic (SNP) markers associated with cold tolerance. The survival of two lines (PT11 and IR11) with opposite extreme cold tolerance pheno- and genotypes was evaluated in diatomaceous earth formulation at 2°C with the cold tolerant IR11 surviving 3 days longer than PT11. Our study yields a set of valuable SNP markers employable in rapid genotyping of cold tolerance and tracking this trait during the breeding process.