Diatomaceous Earth Products Research Articles

Individual and combined effects of α-Pinene and a native diatomaceous earth product on control of stored product beetle pests

The development of alternatives to chemical insecticides has been an attractive topic in stored product pest management due to the limited number of options. This study examined the individual and combined activities of two promising eco-friendly alternatives, the diatomaceous earth product Detech® and the plant-based essential oil α-pinene, against Sitophilus granarius (L.), S. zeamais Motschulsky, 1855 (Coleoptera: Curculionidae), Tribolium confusum Jaquelin Du Val, 1868 (Coleoptera: Tenebrionidae) and Rhyzopertha dominica (Fabricius, 1792) (Coleoptera: Bostrichidae) under laboratory conditions. Individual and combined insecticidal effects of Detech® and α-pinene were evaluated by their direct application to wheat or maize. Complete mortality against S. granarius, R. dominica, and T. confusum occurred at 2 days with 10 and 15 ppm of α-pinene, while 15 ppm of α-pinene produced 100% mortality after 3 days of exposure for S. zeamais. The highest mortality with Detech® was 38.6% at 21 days using 500 ppm for S. zeamais, while it was 51.7 % against S. granarius, and 72.7 % against R. dominica. Detech® did not show any significant activity against T. confusum at any application level. Combined applications of Detech®+α-pinene demonstrated the highest mortality on R. dominica (40.4% mortality), S. zeamais (27.9%), and S. granarius (18.5%), while no significant effect was found on T. confusum (1.1%). Overall, α-pinene was more effective than Detech® against all four tested beetles species. Combined applications led to reduced mortality.

Desiccant Dusts, With and Without Bioactive Botanicals, Lethal to Rhipicephalus (Boophilus) microplus Canestrini (Ixodida: Ixodidae) in the Laboratory and on Cattle.

The exotic southern cattle fever tick, Rhipicephalus (Boophilus) microplus (Canestrini) (Ixodida: Ixodidae), since its eradication from the United States in 1943, made a strong incursion into Texas, beginning 2016. The pest is arguably the most economically detrimental ectoparasite of cattle, Bos taurus L., worldwide. Current R. (B.) microplus control mostly relies on conventional synthetic acaricides to which the ixodid has been developing resistance. Our study demonstrates that commercially available desiccant dust products, with and without bioactive botanical additives, are strongly lethal, when applied dry, against larval R. (B.) microplus in the laboratory, and after being released on dust-treated cattle. Deadzone (renamed Celite 610, a diatomaceous earth product), Drione (silica gel + pyrethrins + piperonyl butoxide synergist), and EcoVia (silica gel + thyme oil), each prophylactically prevented larval R. (B.) microplus from attaching to and feeding on stanchioned calves. Desiccant dust-based products are less likely than conventional synthetic acaricides to decline in terms of efficacy as a result of ixodid resistance, and other desiccant dust advantages, including extended residual, flexibility in terms of application methods, environmental, animal, and human safety, and possible compatibility with organic, or 'green', production systems, are discussed. We anticipate that the desiccant dusts we evaluated, and others not included in this study (e.g., kaolin, perlite, and silica gel) will be effective when used with other control tactics in integrated pest management approaches for controlling R. (B.) microplus (and other ixodid species).

Does diatomaceous earth (DE) cause mortality on Apis mellifera and Bombus terrestris?

Bees play an essential role in the sustainability of terrestrial and agricultural ecosystems as pollinators. However, external factors such as pesticides can negatively affect both bees and plants pollinated by bees, as well as human health. Therefore, less toxic or non-toxic plant protection products have become a popular research topic for a sustainable environment. The purpose of this study was to determine the effects of four different commercial products of diatomaceous earth (Bio, Demite, Detech, Detech WP) on workers of Apis mellifera and Bombus terrestris under controlled laboratory conditions. Each diatomaceous earth product was sprayed on the bees as dust particles for 15 seconds at Maximum Field Dose (10 g/m2). While the worker bees in positive control groups (control +) were exposed to flour, those in the negative control groups (control –) were not exposed to any treatment. The highest mortality rates for B. terrestris and A. mellifera were 22% in Detech WP and 16% in Demite, respectively. However, since mortality rates were under 25% for all the tested DE products, they were classified as harmless for both bee species. Additionally, the direct effect of diatomaceous earth products on honey bees and bumble bees was revealed for the first time in this study.

English

The herein reported study was conducted to evaluate the parasitic potential of Anisopteromalus calandrae (Howard) against larvae of Callosobruchus maculatus (F.), Rhyzopertha dominica (F.) and Sitophilus oryzae (L.) while, adult pests on the food medium treated with two formulations of diatomaceous earth (DE); Marine (Celite) and fresh water (Perma Guard) as grain protectants. The DE was applied at three dose rates i.e., 200, 400 and 600 ppm, at 25°C temperature and 65% relative humidity. Mortality and emergence of adults of tested insects and parasitoid were observed after 14 and 28 days of exposure respectivly. The highest mortality of C. maculatus was 43.37% against higher dose of Perma Guard (600 ppm) while the maximum mortality of S. oryzae was recorded 39.56% on application of Celite (600 ppm). The maximum mortality of A. calandrae parasitoid was observed 66.86% in S. oryzae infested grains treated with higher dose of Perma Guard (600 ppm), while 63.81% mortality of parasitoid was observed in S. oryzae infested grains at higher dose of Celite DE (600 ppm). The Perma Guard effectively controls population of tested insect’s mortality than the Celite. The highest emergence of C maculatus observed was 62.44% at lower dose of 200 ppm of Perma Guard DE while the highest emergence recorded on application of Celite was 60.66% from C. maculatus. The highest emergence of A. calandrae was 65.65% from S. oryzae at lower dose of 200 ppm of Perma Guard DE while the highest emergence of parasitoid recorded on application of Celite was found 60.66% at lower dose of 200 ppm from C maculatus. The emergence of tested insects and parasitoid increased with the decrease in dose rate of DE in most of the tested combinations. Higher dose (600 ppm) of both DE (Celite and Perma Guard) used in experiment showed mortality of tested insects and parasitoid activity of Anisopteromalus calandrae and furthermore release of A. calandrae on host insects would be adversely affected by use of diatomaceous earth product on stored grains. The experiments were carried out in laboratory of Grain Research, Training and Storage Management cell, Department of Entomology, University of Agriculture Faisalabad.

Efficient removal of bacteria from aqueous media with kaolinite and diatomaceous earth products.

To understand the relationships between physical and chemical parameters of kaolinite and diatomaceous earth, and their capacities to remove bacteria from aqueous media. To determine the optimal aqueous media parameters for use of these products in water disinfection processes. Seven kaolinite and three diatomaceous earth products were evaluated. Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus megaterium were used as proxy for bacterial pathogens. Fully calcined kaolin and amorphous diatomaceous earth demonstrated the highest extent and consistency in removing all the bacteria. The removal depended on ionic strength and pH of aqueous media with 100mmoll-1 pH 5 potassium hydrogen phthalate buffer revealing the highest (2 log per gram) extent of the removal. Al3+ cations enhanced sorption up to 4 log per gram. Calcined kaolin and amorphous diatomaceous earth are excellent sorbents for bacteria. Fully calcined kaolin and amorphous diatomaceous earth are perspective tools for wastewater and water disinfection against waterborne bacterial pathogens.

Effects of Diatomaceous Earth on House Dust Mite Sensitization in BALB/c Mice

House Dust Mite (HDM) is associated with hypersensitivity such as asthma. Patients with asthma benefit from improved living environment by reducing HDM exposure. In this study, we examined the effects of commercialized diatomaceous earth product, Casaggia® used as construction materials, on hypersensitivity in HDM-sensitized mice. Male mice were sensitized with house dust mite extract for 7d and then housed in diatomaceous earth (DE)-coated cages for 14 days at Animal Center of the Taichung Veterans General Hospital, Taichung, Taiwan in 2014. Levels of cytokine were determined using ELISA. White blood cell counts were recorded over 21d. Histological analysis was conducted to determine the remodeling of respiratory tract. Exposure to DE resulted in a suppression in elevated eosinophilia induced by HDM in mice. In addition, elevated serum IgE responding to HDM sensitization were restored in the presence of DE. DE ameliorated the inflammation progression in airway. Environmental exposure to DE is suggested to benefit patients with hypersensitivity through relieving inflammatory symptoms. In a sense of prevention, DE represents a potential material against development of asthma.

Tylosin sorption to diatomaceous earth described by Langmuir isotherm and Freundlich isotherm models

Tylosin, an antibiotic used for maintaining livestock health, is a macrolide structurally similar to a number of important, often prescribed human antibiotics. Because of this relationship, tylosin presents a potential threat of antimicrobial resistance from environmental buildup. This work investigated tylosin sorption to natural diatomaceous earth product (DE) and the types of physical interactions responsible for sorption. Most sorption processes were best described by the Langmuir model when compared with Freundlich model. Heat of sorption (ΔH) was 1.14 kJ mol−1 indicating a physisorption process. Change in entropy (ΔS) was 119 J mol−1. Sorption was evaluated from aqueous solution with various H+, KCl and Urea concentrations. In 0.01 M phosphate buffer (PB) pH 6.6, a maximum sorption capacity of 15 mg tylosin per g of DE was achieved. Changing the pH to 2.9 or 11.2 resulted in decreased sorption of tylosin (13 and 10 mg g−1, respectively). Addition of 1 M KCl to 0.01 M PB pH 6.6 decreased sorption of tylosin to DE with the maximum binding capacity of 7 mg g−1. Sorption in 1.0 M urea, 0.01 M phosphate buffer pH 6.6 showed a maximum sorption of 13 mg g−1. Based on these results, the sorption of tylosin appears to be a physisorption process, with charge-charge interactions being the mode of sorption at neutral pH and small contributions from secondary interactions. This information will be useful for developing effective strategies for mitigating tylosin and other antimicrobial's impact on the environment.

Appraisal of selected osmoprotectants and carriers for formulating Gram-negative biocontrol agents active against Fusarium dry rot on potatoes in storage

The production of a dry formulation containing a high titer of viable cells of a Gram-negative biological control agent is a challenging and critically important step in developing the agent into a commercial product. Producing a dry formulation using methods based on air-drying is especially attractive economically. Pseudomonas fluorescens strains S11P12, P22Y05, and S22T04 reduce Fusarium dry rot of potatoes in storage. The relative number of cells of each strain that survived air-drying after 24h of cell growth in a liquid medium and treatment with carbohydrate-based osmoprotectants was determined using a high-throughput microtiter plate assay. Fructose and trehalose at 20gL−1 were the most effective osmoprotectants when results were pooled across strains (P⩽0.05, FPLSD) though osmoprotectant influence on cell survival varied between strains. Different grades of diatomaceous earth, perlite, fumed silica and clay were then combined with suspensions of washed cells of each strain. After 15–18h in an air-drier with relative humidity controlled at 50–60%, diatomaceous earth products Kenite® 700 and HYFLO® were superior in maintaining cell viability though, in the absence of osmoprotectants, log10CFUg−1 of these products dropped by 3 or more log units 24h after drying. Air-dried products resulting from combining cells suspended in 20gL−1 trehalose or fructose with Kenite® 700 and HYFLO® often reduced Fusarium dry rot by >60% (P⩽0.05) for strains P22Y05 and S22T04 but S11P12 products were not as effective in laboratory assays. In a small pilot-scale test, dry formulations of these strains and the fungicide Stadium™ reduced dry rot decay by approximately 20% and 55%, respectively (P⩽0.05).

Studies on the ability of two isolates of Bacillus thuringiensis, an isolate of Clonostachys rosea f. rosea and a diatomaceous earth product to control gastrointestinal nematodes of sheep

Nematode parasites have developed resistance to anthelmintics. Biological control of gastrointestinal nematodes (GIN) in sheep is a promising non-chemical control method. Two experiments were done using Merino sheep. In each experiment, gender, initial egg count per gram (EPG) and initial body weight (BW) aided in placing animals into four groups, each of which was randomly fed with one of four treatments. Experiment 1 evaluated anthelmintic effects of Bacillus thuringiensis Berliner (Bt), Clonostachys rosea f. rosea Schroers (C. rosea) and diatomaceous earth (DE) in sheep. Bacillus thuringiensis and C. rosea were fed to sheep at a rate of 1 g kg−1 BW, and DE was fed at 2% of sheep diet. Relative to the control, treatments had no effect (P>0.05) on EPG, but reduced (P<0.001) larvae per gram (LPG) in faecal culture. Efficacy varied with time (P<0.001). On Day 7, Bt, C. rosea and DE had efficacies of 76, 87 and 61%, respectively. In experiment 2, efficacy of feeding 1 g kg−1 BW of C. rosea chlamydospores to sheep every day, every second day and every third day was tested. Daily feeding of fungal chlamydospores had no effect on EPG (P>0.05), but reduced (P<0.001) LPG (12±1.67) more than every second day (39±0.77) or third day (58±1.77). On Day 12, feeding daily, every second day and every third day had efficacies of 90, 63 and 49%, respectively. These studies suggest that each of Bt, C. rosea isolates and DE products has a potential to affect nematode larvae, and daily use of C. rosea had the highest effect as a biological control of nematodes in this study.

Surface Reactivity, Cytotoxic, and Morphological Transforming Effects of Diatomaceous Earth Products in Syrian Hamster Embryo Cells

In order to evaluate the effect of thermal treatments on the surface reactivity and carcinogenic potential of diatomaceous earth (DE) products, the physicochemical features of some specimens--derived by heating the same original material--were compared with their cytotoxic and transforming potency. The samples were an untreated DE (amorphous) progressively heated in the laboratory at 900 degrees C (DE 900) and 1200 degrees C (DE 1200) and a commercial product manufactured from the same DE (Chd) from which the finer fraction (< 10-microm diameter) was separated (Chd-F). Quartz (Min-U-Sil 5) and a vitreous silica (amorphous) smoothed up with hydrofluoric acid and were used as positive and negative controls, respectively. All samples were analyzed for their degree of crystallization, for their ability to release free radicals and reactive oxygen species, and for their cytotoxic and transforming potencies in Syrian hamster embryo (SHE) cells. X-ray diffractometry showed that DE 900, like DE, was still amorphous, whereas DE 1200 as well as the commercial product (Chd) were partially crystallized into cristobalite. The ability of the dust to release hydroxyl (*OH) radicals in the presence of hydrogen peroxide, as revealed by the spin-trapping technique, was as follows: Chd-F, DE 1200 > Chd > DE 900 > DE, suggesting that on heating, the surface acquires a higher potential for free radical release. Most of the silica samples generated COO* radicals from the formate ion, following homolytic rupture of the carbon-hydrogen bond, in the presence of ascorbic acid. A concentration-dependent decrease in cell proliferation and colony-forming efficiency was observed in SHE cultures treated with Chd-F, Chd, and DE. Heating abolished DE cytotoxicity but conferred a transforming ability to thermal treated particles. DE was the only sample that did not induce morphological transformation of cells. According to their transformation capacity, the samples were classified as follows: Chd-F > Chd, DE 1200 > DE 900 >> DE. Taken together, the reported results suggest that (1) the transforming potential of a biogenic amorphous silica is related to the thermal treatment that transforms the original structure in cristobalite and generates surface active sites; (2) the reactivity of samples in releasing *OH radicals correlates to their transforming ability; (3) the finer fraction of the commercial product is significantly more toxic and transforming than the coarse dust; and (4) opposite to silica dusts of mineral origin, which loose both cytotoxicity and transforming ability upon heating, heated diatomite acquires a cell-transforming potency. DE products should be thus considered a set apart of silica-based potentially toxic materials.

Small-scale farmer perceptions of diatomaceous earth products as potential stored grain protectants in Zimbabwe

Farmers repeated prioritisation of the need for improved methods of controlling insect damage to stored commodities in Zimbabwe led to the search for alternative grain protectants to the locally available organophosphate-based pesticides. In field trials the diatomaceous earth (DE) products, Protect-It ® and Dryacide ®, gave good protection to threshed maize, sorghum and cowpea from insect attack during 8 months storage, enabling households to increase both their food security and control over grain sales. However the initial trials, although on-farm, were researcher-managed and only evaluated by farmers at the end of the storage period. No information existed on how effective DEs were under real farmer management. At the start of the 1999/2000 storage season, farmers in Buhera and Binga districts set up trials in their own granaries using their own maize and sorghum grain, respectively. During a 7 months storage period they evaluated the application of 0.1% w/w Protect-It ® compared to their typical grain protection methods. At 5 and 7 months storage, farmers compared the treatments using the parameters they view as important such as insect damage, expected ‘sadza’ yield and quality and sale price. The DE treatments outscored other practices for all parameters and farmers were keen to purchase DEs to protect their future harvests. Grain samples from the same trial were also analysed in the laboratory at 5 and 7 months for insect populations, damage and moisture content. Although grain damage and insect numbers were higher in the typical grain protection treatment than the DE treatment, the differences were not statistically significant.

Bioremediation of Perchlorate-Contaminated Groundwater Using a Packed Bed Biological Reactor

ABSTRACT The objective of this study was to assess the efficacy of a bench-scale, acetate-fed, packed bed bioreactor (PBR) to treat low concentrations (>1 mg L−1) of perchlorate (ClO4 −) in groundwater collected from an impacted site. The PBR consisted of a cylindrical plexiglass column packed with Celite, a diatomaceous earth product, as a solid support medium. The reactor was inoculated with a ClO−4 −-reducing bacterial isolate, perclace. Results showed that with influent ClO4 − concentrations of approximately 800 μg L−1, nondetectable effluent concentrations (>4 μg L−1) were achieved with the PBR/perclace system at residence time as low as 0.3 h. Influent acetate concentrations of less than 500 mg L−1 yielded nondetectable effluent ClO− 4 concentrations, and acetate concentrations generally less than 50 mg L−1 were present in the effluent. Nitrate (NO− −3) was also removed in this system, while sulfate (SO4 2−) reduction was not observed. The pH remained relatively constant during the process.

Treatment of rice with diatomaceous earth and effects on the mortality of the Red flour beetle Tribolium castaneum (Herbst)

AbstractDiatomaceous earth has been demonstrated in Australia, Germany, and the USA to protect stored products from infestation by insect pests. However, application of diatomaceous earth has rarely been used in Asian countries for the protection of stored grain from insect damage. These facts and the paucity of existing data from the tropics prompted the present study of storage with diatomaceous earth. We exposed rice treated with the diatomaceous earth product Fossil Shield® to infestation by Tribolium castaneum Herbst. During the dry season, when tests were conducted, the mean temperature was 29 ± 2 °C and relative humidity was 80 ± 3 %. The population of T. castaneum in rice was significantly reduced after treatment with Fossil Shield®. Diatomaceous earth at 1 g and 2 g per kilogram rice reduced population growth of T. castaneum to a coefficient of 0.27, and 0.02 respectively after 42 days. Fossil Shield® at 0.5 g per kilogram rice increased the mortality of T. castaneum, but did not stop population growth.

Effects of Protect-It on Efficacy ofAnisopteromalus calandrae(Hymenoptera: Pteromalidae) Parasitizing Rice Weevils (Coleoptera: Curculionidae) in Wheat

The parasitoid Anisopteromalus calandrae (Howard) was very sensitive to direct contact with Protect-It, an inert dust formulation containing 90% diatomaceous earth and 10% silica aerogel. LT 50 s at room temperature and humidity were 49 min (95% CL = 48-51) and 72 min (95% CL = 69-74) for males and females, respectively, in petri dishes containing 2.5 mg dust per square centimeter. Under the same conditions, adults of the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae), a host of A. calandrae, were much less sensitive. Mortality of S. oryzae after a 24-h contact period was 50% for females and 62% for males. When tested in no-choice laboratory bioassays at 27°C, label rates of Protect-It (200 and 400 ppm) dusted onto hard red winter wheat, Triticum aestivum. L. (13.9% moisture content) that was infested with immature rice weevils reduced the longevity of parent A. calandrae females and significantly reduced parasitization of the weevils at 3 tested humidities, 43, 60, and 75% RH. Parasitoid progeny production was also significantly reduced. At 75% RH, 92.8 ± 2.9 parasitoid progeny were produced in untreated wheat compared with 12.6 ± 2.6 progeny in the treated wheat. Sex ratio of parasitoid progeny was not significantly affected by the dust treatments at any relative humidity. In two-choice tests in divided petri dish arenas, single A calandrae females showed a strong avoidance of Protect-It-treated wheat and a significant preference for parasitizing weevils in untreated wheat. However, significantly more parasitoid progeny were produced in dishes in which one-half contained Protect-It-treated wheat and the other half contained untreated wheat compared with dishes in which both halves of the divided dishes held untreated wheat. Reasons for the Protect-It-stimulated oviposition response by A. calandrae are not known, but may be related to stress induced by the dust. In separate tests, there was no significant difference in emergence of weevils from treated or untreated wheat, regardless of the weevil age at time of dusting, or the relative humidity at which the dusted wheat was maintained. Our studies provide evidence that any natural control of pest insects exerted by local populations of parasitoids, or enhanced biological control by augmentative releases of parasitoids, would be adversely affected by the use of Protect-It or other diatomaceous earth products on stored grain.

A method for determination of inorganic dust content of grain in the presence of grain dust

Summary. A method was developed for the determination of insecticidal ‘inert dusts’, particularly the diatomaceous earth product Dryacide, on grain. The method was also evaluated for another physical insecticide, magnesite, and 2 standard clays, bentonite and kaolin. The method consists of isolation of dusts (both inert dust and grain dust) from grain, followed by density centrifugation and ashing of the bottom pellet. The ash content of the bottom pellet is linearly related to the percentage inorganic dust in grain dust (w/w). The method can serve 2 functions. First, it can quantify total inorganic ash. Second, it can quantify the total amount of a specific inorganic additive, for example, Dryacide, thus enabling studies on the fate of inorganic additives during grain processing.

In vitro cytotoxicity and quantitative silica analysis of diatomaceous earth products.

Mouse peritoneal macrophages were used to evaluate the relative cytotoxicity of a series of diatomaceous earth products in vitro. The amorphous and crystalline silica content of the products was determined by a combination of infrared spectroscopy and x ray powder diffraction techniques. The cytotoxicities of the high cristobalite content flux calcined materials were similar to that of the standard cristobalite ; both the natural and straight calcined materials had significantly greater activities than the flux calcined materials. Thus within the limitations of the macrophage cytotoxicity test the hypothesis that crystalline content is the only determinant of fibrogenicity of diatomaceous earth is not supported.