Dominica Adults Research Articles

Insecticidal efficacy of local diatomaceous earth compositions with different particle sizes against stored grain pests

In this study, the efficacy of a mixture of local diatomaceous earth (DE) with different diatomite compositions and particle sizes against stored-grain pests, Sitophilus oryzae L., 1763 (Coleoptera: Curculionidae), Tribolium confusum du Val, 1863 (Coleoptera: Tenebrionidae), and Rhyzopertha dominica (F., 1792) (Coleoptera: Bostrichidae) adults was investigated in 2023 in the Entomology Laboratory of the Department of Plant Protection, Faculty of Agriculture, KSU. In biological tests, 500 and 1000 ppm concentrations (mg DE/kg wheat) of different particle sizes (≤ 20, 20-75, 75-150, and ≥ 150 µm) of DE mixture and original DE (≤ 250 µm) were applied to wheat. The highest mortality rate for all insect species tested at 500 ppm was obtained from DE treatments of ≤20 µm. At 1000 ppm, 100% mortality was observed for T. confusum and S. oryzae in almost all particle size DE-treatments, whereas no local DE treatments resulted in 100% mortality for R. dominica adults. Moreover, the greatest reduction in the number of F1 generation adults for S. oryzae and R. dominica was obtained in the DE treatment of ≤20 µm at 500 and 1000 ppm. In conclusion, local DE mixture treatments with ≤ 20 µm particle size were found to be highly effective in the control of stored-grain pests.

Behavioural responses of Sitophilus granarius (L.) and Rhyzoperta dominica (F.) to odours of old and modern wheat genotypes

Sitophilus granarius (L.) and Rhyzopertha dominica (F.) are among the major stored-product pests worldwide. The identification of low or un-attractive wheat genotypes toward storage pests and their Volatile Organic Compounds (VOCs) profile is useful in breeding programs and in characterization of behaviourally active compounds suitable in developing semiochemical-based control means. Old wheat cultivars are genetic resources useful for breeding purposes. In this study, the VOC profiles of old genotypes, Senatore Cappelli, old Saragolla, Dauno III, and modern wheat varieties, Mec, Ofanto, Svevo, and Faridur, were characterized by headspace - solid phase microextraction (HD-SPME) and gaschromatography coupled with mass spectrometry (GC-MS) and their attractiveness towards S. granarius and R. dominica adults was evaluated in two-choice pitfall bioassays and Y-tube olfactometer, respectively. Sitophilus granarius adults were significantly attracted to odours of all varieties, with females being significantly more attracted by Faridur, Ofanto, Mec, and old Saragolla compared to Svevo. Rhyzopertha dominica males and females exhibited a significant olfactory preference for the odours of Faridur, Mec, and old Saragolla. The olfactory preferences of both species could be related to differences emerged in varietal VOC profiles. The most attractive variety for both species, Faridur, was rich in alcohols, alkanes, and terpenes. Old Saragolla, Ofanto, and Mec were rich in alcohols and organic acids. Dauno III was the richest variety in alcohols and lactones, and the poorest in aldehydes and terpenes compared to other varieties. Svevo showed the lowest amounts of alcohols and the highest value of aldehydes; Senatore Cappelli was rich in aldehydes, organic acids, and alkanes. The possible effects of the differences in VOC profiles on the olfactory preferences of insects are discussed. The study offers new knowledge for further investigation testing VOCs of the most and the lowest attractive varieties to identify effective attractants or strong repellents towards S. granarius and R. dominica.

Insecticidal, physiological, and biochemical effects of Schinus molle essential oil on the adults of Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae)

Rhyzopertha dominica (F.) is considered as a major stored product pest. Conventional insecticides induce adverse effects on the environment. Plant derivative products constitute a promising alternative for pest control. The purpose of our research was to identify the chemical profile of essential oil (EO) extracted from Schinus molle L. (Anacardiaceae) and to evaluate the fumigant and the contact toxicity, and the repellent activity of this oil on adults of Rhyzopertha dominica F. (Coleoptera), a major pest in products that are stored around the world. The effects of this oil were examined on biochemical profile (energy reserves and Proteins), selective biomarkers like acetylcholinesterase (AChE), glutathione S-transferases (GST) and glutathione (GSH), and nucleic acids (DNA and RNA). Digestive enzymes were also investigated. The major chemical compounds identified by the GC-MS were α-phellandrene (16.613%), ß-phellandrene (12.104%), elemol (9.028%) and β-eudesmol (5.872%). Then, we evaluated the repellent activity, and also the effects in nutritional reserves and some biomarkers. This EO exhibited an insecticidal and repellent activity as a function of the exposure time and concentrations. Contact (LC50 at 24 h: 19.99 μL/mL) is the most effective mode of application compared to fumigation (LC50 at 24h: 174.30 μL/L air). S. molle EO was also investigated in digestive enzymes’ activities (α-amylase, lipase, chitinase and protease). Our results revealed a decrease in both α-amylase, lipase, protease and chitinase activities in treated adults compared to controls. In addition, we noticed a neurotoxic activity of S. molle EO traduced by a decrease of AChE. An induction of the detoxification system was observed via a decrease in GSH rate and an increase in GST activity. Moreover, the treatment induces an alteration of biochemical profile of R. dominica adults. Lastly, essential oil was examined on nucleic acids. Results showed an increase in DNA and RNA amount in treated adults when compared with control. Due to their effective source of bioactive compounds, the EO from the studied plant could be used as an alternative strategy for the management of stored product pests.

Efficacy of two amorphous silica powders applied to soft red winter wheat against the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae)

The increased demand for residue-free grains and development of insect resistance to insecticides has led to a surge in the utilization of diatomaceous earths as grain protectants. Diatomaceous earth formulations, effective at lower application rates, are crucial for managing stored product insects without compromising grain quality. In this study, the efficacy of two different amorphous silica powders applied to soft red winter wheat was tested against the lesser grain borer, Rhyzopertha dominica (F.). Twenty adults of R. dominica were exposed to 100 g of organic soft red winter wheat admixed with varying application rates (0 for the untreated control, 0.05, 0.1, 0.15, and 0.20 g/kg) of silica powders 1 and 2. Mortality assessments were made after 14 d of exposure, and data on adult progeny production, insect-damaged kernels, and grain weight loss were determined at 42 d. Exposing R. dominica adults to wheat treated with 0.20 g/kg of silica powder 1 resulted in a mean ± SE of 94.5 ± 5.5% mortality and 1.3 ± 1.3 adult progeny production. Insect-damaged kernels and grain weight loss caused by R. dominica exposed to 0.20 g/kg of silica powder 1 were 0.19 ± 0.19 and 0.1 ± 0.1%, respectively. Exposure of R. dominica adults exposed to wheat mixed with 0.20 g/kg of silica powder 2 resulted in complete mortality, with no observed adult progeny production, insect-damaged kernels, or grain weight loss. Overall, silica powder 2 exhibited greater efficacy than silica powder 1, and this superior performance can be attributed to its higher oil adsorption capability and low pH (<8.5) value.

Susceptibility of Rhyzopertha dominica (Coleoptera: Bostrichidae) and Sitophilus oryzae (Coleoptera: Curculionidae) to the fungal entomopathogen Beauveria bassiana (Balsamo-Crivelli) Vuillemin s.l. (Hypocreales: Clavicipitaceae)

Control measures of stored grain pests include the excessive utilization of chemical insecticides that generate negative environmental impact. Current trends in integrated pest management are oriented towards the preservation of the environment using natural biopesticides, among these products arise entomopathogenic fungi. This study aimed to test the efficacy of a native strain of Beauveria bassiana to control two main stored grain pests such as Sitophilus oryzae and Rhyzopertha dominica and also evaluate the persistence of the fungus on wheat grains. The B. bassiana strain controlled 89%±0.07 of R. dominica adults and 80% ±0.14 of S. oryzae. The survival analysis showed that MST was 4.27 ±0.19 days for R. dominica adults and 4.27 ±0.20 days for S. oryzae. Furthermore, results of long rank test for the comparison of the Kaplan-Meier curves did not present significant differences between the survival of both stored grain pests. Dual choice tests demonstrated that B. bassiana LPSc1227 presented a repellent action against both stored grain pests. The seed persistence of conidia was 100% in treated seeds after 45 days. Further research will contribute to elucidate more insecticidal features of the B. bassiana LPSc 1227 strain against S. oryzae and R. dominica, two main stored grain insect pests. Highlights: bassiana presented insecticidal activity against R. dominica and S. oryzae. bassiana demonstrated a repellent action against both stored grain pests. bassiana was able to persist on the surface of wheat grains after 45 days storage.

Formulation of pectin-Citrus aurantium essential oil-based packaging film and assessment of insecticidal performances against Rhyzopertha dominica on stored wheat

In stored wheat products, Rhyzopertha dominica (F) (Coleoptera: Bostrichidae) is an important pest that results in significant economic losses. Insect physiology and behavior can be affected by bioactive compounds extracted from plant wastes, which are important tools for developing bioincesticides. The purpose of this study is to develop an insecticidal packaging film based on pectin and essential oil (EO) extracted from Citrus aurantium (L., 1753) fruit peels.The encapsulation efficiency (EE) and cumulative release (CR) of C. aurantium EO into pectin film were determined. Further, Film packaging was tested against Rhyzopertha dominica adults reared on Karim and Khiar durum wheat (Tritichum durum Desf.) varieties. The fumigant toxicity was assessed after 10, 20, 30 and 40 days of storage. Moreover, emergence inhibition of R. dominica adults was determined. In addition, germination rate, weight loss and grain damage were examined.Results revealed that the lethal concentration that killed 50 % of the exposed adults developed into karim and khiar varieties were 278.45 and 688.79 µL/L air, respectively. Moreover, high encapsulation efficiency of C. aurantium essential oil into pectin film with an EE = 80.6 %. Moreover, pectin: EO film achieved complete (100 %) mortality and emergence inhibition of R. dominica adults for all storage periods. Also, pectin: EO film represent the better treatment which preserve the quality and quantity of wheat grains as well as grain damage, weight loss and germination rate. To concludepectin- C. aurantium EO film showed a significant fumigant effect against R. dominica adults and the emergence of their descendants after different storage periods and could be recommended as an active ingredient for a natural packaging against stored product insects.

Insecticidal activity of Iranian diatomaceous earth, alone or in combination with Mentha longifolia plant extract to control Rhyzopertha dominica adults on different cereals

Insecticidal activity of Iranian diatomaceous earth, alone or in combination with Mentha longifolia plant extract to control Rhyzopertha dominica adults on different cereals

Etofenprox guarding concrete for six weeks: immediate and delayed mortality of three major stored-product coleopterans

This study addresses the residual efficacy of the pyrethroid insecticide etofenprox sprayed on concrete surfaces for the management of Prostephanus truncatus (Horn) (Coleoptera: Bostrychidae) adults, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) adults, and Trogoderma granarium Everts (Coleoptera: Dermestidae) adults and larvae, through a period of six weeks. Three doses of etofenprox (5 μg/cm2, 15 μg/cm2, and 45 μg/cm2) were tested to assess immediate (1, 2, 3, and 7 days of exposure) and delayed (7 days post-exposure) mortality. For P. truncatus, after 7 days of exposure, immediate mortality ranged between 35.6% and 53.3% the first week while the sixth week ranged from 12.2% to 27.8% after a gradual decrease the weeks in-between. Similarly, at the same exposure interval, the tested doses of etofenprox killed 36.7–62.2% of R. dominica the first week while 20.0–41.1% the sixth week. Etofenprox provided the highest mortality rates against T. granarium adults reaching 93.3–97.8% the first week. After a progressive decrease, mortalities ranged from 73.3% to 87.8% the sixth week. Regarding T. granarium larvae, 43.3–63.3% of the exposed individuals died the first week but during the last week mortalities decreased to 13.3–32.2%. Delayed mortality of all tested species/developmental stages was elevated the first week, reaching 100.0% for all tested doses against P. truncatus and T. granarium adults. During the last week, 45 μg/cm2 killed 100.0% of P. truncatus adults, 67.4% of R. dominica adults, and 42.9% and 31.1% of T. granarium adults and larvae respectively. The results indicate that the efficacy of etofenprox on concrete depends on the pest species/developmental stages that are exposed and/or the time that has passed since the application date.

Insecticidal Effect of Bularafa Raw Diatomaceous Earth (BRDE) Against Rhyzopertha dominica (F.) on Stored Maize (Zea mays L.) and Sorghum (Sorghum bicolor [L.] Moench) Grains

The toxicity of Bularafa raw diatomaceous earth (BRDE) to Rhyzopertha dominica adults on stored maize and sorghum grains was conducted under ambient laboratory conditions (31-34oC and 24 – 30% R.H.). The BRDE was tested at doses: 0 (untreated control), 250, 500, 1,000 1,500, and 2000 mg/kg and Protect-It® at 1000 mg/kg of grain which served as a check. Thirty (30) mixed-sex adult insects were exposed to 50 g of freshly treated grains, and mortality was observed after 7 and 14 days. The results showed that a higher number of exposed Rhyzopertha dominica adults died on maize than on sorghum, and mortality increased with an increase in dose and exposure period. After 7 days of exposure to treated maize and sorghum grains, the LD95 values were 4981 and 5890 mg/kg of BRDE, respectively. The corresponding values after 14 days were 1561 and 3206 mg/kg, respectively

Ozone reduces lifespan and alters gene expression profiles in Rhyzopertha dominica (Fabricius).

Rhyzopertha dominica is one of the most important stored grain pests that seriously damage rice and wheat. At present, the method of controlling stored grain pests mainly relies on insecticide fumigation. However, the excessive use of pesticides not only leaves pesticide residues, with harmful effects on human health and the environment, but also induces insect resistance. Ozone is a strong oxidant with the characteristics of easy decomposition and without residue. Although ozone has been widely used in the food industry in recent years, research on the control of stored grain pests is limited. In this research, we used ozone treatment to control R. dominica adults and explore the molecular mechanisms that affect them. Here, we found that ozone treatment on R. dominica adults could decrease life span and increase malondialdehyde (MDA) content, as well as reduce activity of total superoxide dismutase (SOD) and catalase (CAT). Using RNA-seq technology, we identified 641 genes that were differentially expressed between ozone-treated and control R. dominica adults [fold-change of ≥ 2 (q-value < 5%)]. When comparing ozone treatment with control R. dominica adults, 330 genes were significantly upregulated and 311 were downregulated. RT-qPCR confirmed that 11 genes were differentially expressed in ozone-treated and control R. dominica adults. These genes were involved in insect cuticle protein and antioxidant system. This research showed that ozone treatment could reduce the lifespan of R. dominica through antioxidant system. It is an environmentally benign method for the control of stored grain pests and has great development potential.

Insecticidal properties of etofenprox for the control of Ephestia kuehniella, Rhyzopertha dominica, Sitophilus oryzae, and Tribolium confusum on stored barley, maize, oats, rice, and wheat.

Etofenprox is a novel pyrethroid insecticide that targets the nervous system of insects by affecting the function of the sodium channel. The current study examines the insecticidal activity of etofenprox against Ephestia kuehniella (Lepidoptera: Pyralidae) larvae, Rhyzopertha dominica (Coleoptera: Bostrychidae) adults, Sitophilus oryzae (Coleoptera: Curculionidae) adults, and Tribolium confusum (Coleoptera: Tenebrionidae) adults and larvae on different grain commodities. For this purpose, etofenprox was applied on barley, maize, oats, rice, and wheat at 0.1, 1, 5, and 10ppm. Mortality levels were recorded after 7, 14, and 21days of exposure. For E. kuehniella larvae, 10ppm applied on whole rice killed 96.1% of the exposed individuals after 21days of exposure.The application of etofenprox on oats at 5ppm caused the death of 98.3% of the exposed R. dominica adults. Complete mortality was observed for R. dominica adults 21days post-exposure to oats and whole rice treated with 10ppm etofenprox. The highest concentration applied on barley caused 95.0% mortality to S. oryzae adults, while the same concentration on maize killed 76.8% of T. confusum adults after 21days of exposure. Larvae of T. confusum exhibited high mortality levels reaching 99.4% after 21days of exposure to barley treated with 10ppm etofenprox. Progeny production of parental R. dominica adults was almost suppressed on all commodities treated with 5ppm etofenprox. The offspring emergence of S. oryzae ranged between 4.4 and 24.6 adults per vial at 10ppm. No T. confusum progeny was produced at 10ppm etofenprox. Our results document that etofenprox is highly effective as grain protectant against several insect species, their developmental stages and their progeny production, but its performance depends on the type of the commodity that it is applied on.

Promising Insecticidal Efficiency of Essential Oils Isolated from Four Cultivated Eucalyptus Species in Iran against the Lesser Grain Borer, Rhyzopertha dominica (F.).

Simple SummaryEucalyptus essential oils have shown promising insecticidal effects on several insect pests. The lesser grain borer, Rhyzopertha dominica (F.), causes economically significant damage to stored grains as an internal primary insect pest. In this study, the chemical compositions of essential oils isolated from four Eucalyptus species. E. microtheca, E. procera, E. spatulata, and E. torquata were detected and identified using a gas chromatography-mass spectrometer, and their lethal and sublethal insecticidal effects were evaluated against the adults of R. dominica. Although all essential oils have significant fumigant toxicity, due to the high relative potency, R. dominica was more susceptible to the E. procera essential oil than the others. The total protein, glycogen, and lipid contents and digestive amylase and protease enzyme activities of the treated insects were reduced. The nutritional indices consumption index, relative consumption rate, and relative growth rate were also reduced in the treated adults. The findings of this study reveal that E. microtheca, E. procera, E. spatulata, and E. torquata essential oils can be potentially used for the development of eco-friendly natural agents for the management of R. dominica. The lesser grain borer, Rhyzopertha dominica (F.), causes damage to stored grains resulting in both quantitative and qualitative losses. The use of synthetic fumigants in the management of stored-product pests resulted in undesirable side effects such as environmental contamination and threat to human and animal health. In this study, the lethal and sublethal effects of essential oils from four Eucalyptus species, E. microtheca, E. procera, E. spatulata, and E. torquata were studied against R. dominica adults. Gas chromatographic–mass spectral analysis of the essential oils was carried out, in which terpenes such as 1,8-cineole and globulol were abundant in essential oils. The pest was susceptible to the fumigation of the essential oils and, considering concentrations and exposure times (24, 48, and 72 h), had significant effects on the pest mortality. The total protein, glycogen, and lipid contents and digestive amylolytic and proteolytic activities of the adults treated with tested essential oils were reduced. The consumption index, relative consumption rate, and relative growth rate were also reduced in the treated adults. According to the insecticidal effects on the adults of R. dominica, the essential oils of E. microtheca, E. procera, E. spatulata, and E. torquata can be candidates for further investigations as grain protectant agents.

Insecticidal and repellency effects of a Turkish diatomaceous earth formulation (Detech) on adults of three important pests of stored grain

In this study, laboratory experiments were conducted in order to assess the insecticidal and repellency effects of a novel Turkish diatomaceous earth (DE) formulation (Detech) on adults of the rice weevil, Sitophilus oryzae (L., 1763) (Coleoptera: Curculionidae), the confused flour beetle, Tribolium confusum du Val., 1863 (Coleoptera: Tenebrionidae), and the lesser grain borer, Rhyzopertha dominica (F., 1792) (Coleoptera: Bostrichidae). For the insecticidal activity, bioassays were conducted with soft wheat treated with 0, 600 and 900 ppm of Detech at 25 ± 1°C and 65 ± 5% RH and progeny production was assessed after 45 days. For the repellency tests, two-choice tests on mono-layer wheat were conducted at 1,000 ppm of Detech at 25 ± 1°C and 65 ± 5% RH. Overall, Detech was effective against T. confusum and S. oryzae adults in wheat, causing 82% to 100% mortality at 600 and 900 ppm after 7 and 14 days exposure. The complete, or almost complete, progeny inhibition of S. oryzae were found at both concentrations, whereas the highest reduction in R. dominica progeny (84%) was obtained at 900 ppm. Detech was highly and moderately repellent to T. confusum and S. oryzae adults, respectively, whereas it had no or low repellency effect on R. dominica adults. In conclusion, Detech, which consists of a mixture of three DE deposits with different diatom frustules has potential for use against stored-grain insect pests as a promising grain protectant. Experiments were conducted in 2020-2021 in Entomology Laboratory of Tekirdağ Namık Kemal University and Kahramanmaraş Sütçü İmam University.

Seasonal, Landscape, and Attractant Effects on Lesser Grain Borer, Rhyzopertha dominica (F.), Captures in Northeast Kansas

The lesser grain borer, Rhyzopertha dominica (F.), is a highly diverse feeder and widely distributed throughout the United States in agricultural and non-agricultural landscapes. Six four-funnel Lindgren traps were deployed in feed mill, grain elevator, and native prairie landscapes, to determine the most attractive food and pheromone combination (attractant) and patterns in seasonal captures. Traps were baited with combinations of wheat (crimped, high moisture, pre-fed) with or without an R. dominica specific aggregation pheromone in 2017 and 2018. Traps were deployed for 48 h, collected, and the number of R. dominica counted. Rhyzopertha dominica was captured among all landscapes with all attractants. There was a significant correlation between temperature and R. dominica captures, with peak captures occurring during the warmest months. Significantly more R. dominica adults were captured in traps containing the pheromone. In 2017, pheromone traps captured 818% more R. dominica and 543% more than in 2018. The pheromone component in the trap was more attractive than any natural stored wheat condition and should be included in future studies. Understanding the seasonal patterns and changes in capture rates in agricultural and non-agricultural landscapes may be useful in determining times of increased immigration pressure into the newly harvested grain.

Beauveria bassiana Konidilerinin Katı Faz Fermantasyonu ile Kitlesel Üretimi için Bazı Tahılların İncelenmesi

This study was conducted to test five substrates (whole rice, broken rice, dovme, wheat and burghul) for the mass production of Beauveria bassiana isolate 5-4, known to be affective against stored-cereal pests. A solid-state fermentation technique was used, and amount of product, number of conidia, germination, hydrophobicity and thermotolerance of conidia, and their virulence on Rhyzopertha dominica adults were used to evaluate the success of substrates. For production, 100 g of a substrate was used in a polypropylene bag. After sterilization and inoculation, the bags were sealed and incubated for 14 days at 25ºC. Hydrophobicity was assessed using the aqueous-solvent partitioning method with PM buffer, and liquid paraffin as two phases. Thermotolerance tests were conducted by exposing conidia to 35, 40 and 45°C for 15, 30 and 60 minutes. In virulence test, adults were released into 40 gr wheat mixed with conidia and kept at 25oC and 65% relative humidity in darkness for 14 days. The highest amount of product was obtained by using whole rice (4.10g/bag), followed by broken rice, wheat, dövme and burghul. The highest number of conidia was achieved using broken rice (10.24x1010conidia/g) and whole rice (9.62x1010conidia/g). The germination rates of conidia did not vary significantly. Significantly higher hydrophobicity rate was obtained using wheat (88.73%). The conidia from burghul and wheat showed higher thermotolerance than those from other substrates. The conidia obtained from whole rice and broken rice caused 80.3% and 72.0% mortalities, respectively, significantly higher than the others. Rice was found to be a better choice for this isolate as the ultimate purpose is to suppress pest populations, with awareness of its shortcomings. It was found crucial to test all important characteristics of produced conidia together for assessment of substrates.

Immediate and Delayed Mortality of Four Stored-Product Pests on Concrete Surfaces Treated with Chlorantraniliprole.

Simple SummaryWe examined the mortality caused by the anthranilic diamide, chlorantraniliprole, at four different doses applied on concrete (0.01, 0.05, 0.1, and 0.5 mg a.i./cm2) in Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) adults and larvae, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) adults, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) adults, and Acarus siro L. (Sarcoptiformes: Acaridae) adults and nymphs. Mortality data were recorded after 1, 2, 3, 4, and 5 days to determine the immediate mortality. Furthermore, after the 5-day mortality counts, still living individuals were conveyed for 7 days to untreated concrete surfaces to estimate the delayed mortality. The highest immediate mortality was recorded for the larvae of T. castaneum, reaching 96.7%, followed by the adults of A. siro (92.2%) after 5 days of exposure to 0.5 mg a.i./cm2. Complete (100.0%) delayed mortality was noticed for T. castaneum (adults and larvae), S. oryzae, and A. siro (both as adults) at 0.5 mg a.i./cm2. Rhyzopertha dominica adults and A. siro nymphs exhibited 98.6% and 96.3% delayed mortality at the same dose, respectively. Overall, our results demonstrate that chlorantraniliprole is effective against all the species tested, causing varying immediate and delayed mortality rates at the developmental stages tested.Chlorantraniliprole is an effective pesticide against a plethora of pests, but its efficacy against stored-product pests is very poorly explored. In this study we treated concrete surfaces with four different doses of chlorantraniliprole (0.01, 0.05, 0.1, and 0.5 mg a.i./cm2) against the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) adults and larvae, the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae) adults, the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae) adults, and the flour mite, Acarus siro L. (Sarcoptiformes: Acaridae) adults and nymphs, to examine the immediate mortalities after 1, 2, 3, 4, and 5 days of exposure. Additionally, the delayed mortality of the individuals that survived the 5-day exposure was also evaluated after a further 7 days on untreated concrete surfaces. We documented high mortality rates for all tested species and their developmental stages. After 5 days of exposure to 0.5 mg a.i./cm2, T. castaneum larvae and A. siro adults exhibited the highest immediate mortality levels, reaching 96.7% and 92.2%, respectively. Delayed mortality was also very high for all tested species and their developmental stages. Nymphs of A. siro displayed a 96.3% delayed mortality followed by the adults of R. dominica (98.6%) after exposure to 0.5 mg a.i./cm2. All other tested species and their developmental stages reached complete (100.0%) delayed mortality, where even 0.01 mg a.i./cm2 caused ≥86.6% delayed mortality in all species and their developmental stages. Taking into consideration the effectiveness of chlorantraniliprole on this wide range of noxious arthropods, coupled with its low toxicity towards beneficial arthropods and mammals, this pesticide could provide an effective management tool for stored-product pests in storage facilities.

Studies on the application of bio-carbon dioxide as controlled atmosphere on pest management in wheat grain storage

The study evaluated the viability of purified waste gas called bio-CO2 (CO2 ≥ 98%, CH4 ≤ 2.0%, v/v), which is a byproduct from a compressed biogas (CBG) plant, as a new source of CO2 for control atmosphere for wheat grain storage. The findings were compared with the use of pure CO2 on mortality of Rhyzopertha dominica adults, seed germination, and nutritional quality of wheat grain for two and six months storage periods. Fifteen tapered plastic bottles of 1 L storage volume were taken for grain storage. Insect mortality of 100% was found in 1, 3, and 5 days using bio-CO2 and 4, 6, and 8 days with pure CO2 at 80, 60, and 40% concentration, respectively. In control grain infested with R. dominica, the adult insect triplicated in six weeks, 3.9 times in two months, and 10.4 times in 6 months storage. There were no significant differences (p > 0.05) observed in seed weight stored for two and six months under the bio-CO2 fumigation. Whereas, seed weight loss of about 5.03 ± 0.8% in control without infestation and 17.25 ± 1.2% in grain infested with R. dominica were reported over two months storage. Similarly, no weight loss during controlled atmosphere treatment, 12.66 ± 0.34% in control, and 27.42 ± 0.96% with R. dominica were found for six months storage period. The seed germination was significantly affected at 80% CO2 using both the controlled atmosphere for grain stored for six months. The major nutrient contents remained non-significant (p > 0.05) under both the fumigants. Whereas, carbohydrate content was significantly reduced (p < 0.05), and protein content was increased in control without infestation and grain infested with R. dominica.

Etofenprox as grain protectant for the management of five key stored-product insect pests.

Etofenprox is a broad spectrum pyrethroid insecticide with low toxicity to mammals, fishes, and honeybees. In the present study it was evaluated as grain protectant against Ephestia kuehniella (Lepidoptera: Pyralidae) larvae,Prostephanus truncatus (Coleoptera: Bostrychidae) adults,Rhyzopertha dominica (Coleoptera: Bostrychidae) adults, Sitophilus oryzae(Coleoptera: Curculionidae) adults, and Tribolium confusum (Coleoptera: Tenebrionidae) larvae and adults. Etofenprox was applied at 0.1, 1, 5, and 10 ppm on wheat, or maize in the case of P. truncatus, and tested at different combinations of temperatures (20, 25, and 30 °C) and relative humidity (RH) levels (55 and 75%). Progeny production of the tested coleopteran adult species was also assessed. For E. kuehniella, after 21 days of exposure 75.6% of the exposed larvae were killed at 20 and 30 °C/55% RH. Mortality of P. truncatus adults reached 99.4 and 97.8% at 10 ppm of 55 and 75% RH, respectively, at 30 °C. For S. oryzae, after 21 days of exposure, mortality was moderate at both RH levels, even at the elevate doses, reaching 66.7% at 10 ppm at 20°C/75% RH. All R. dominica adults died 21 days post-exposure at 30°C/55% RH and 25 or 30°C/75% RH at 10 ppm. For T. confusum adults, mortality was 81.1% 10 ppm 21 days post-exposure at 20°C/75% RH. Etofenprox killed 99.4% of the exposed T. confusum larvae at 10 ppm respectively 14 days post-exposure at 25°C/55% RH. Concerning progeny production, complete suppression was recorded for P. truncatus, R. dominica, and T. confusum in various combinations of temperature/RH. Our findings indicate that etofenprox is a well-promising insecticide for the protection of stored grains. However, its performance differs among insect species and abiotic conditions.

Combined and individual effects of diatomaceous earth and methyl eugenol against stored products insect pests

The insecticidal activity of a proprietary diatomaceous earth, Detech, and methyl eugenol was tested with Sitophilus granarius (L., 1758), Sitophilus zeamais Motschulsky, 1855 (Coleoptera: Curculionidae), Rhyzopertha dominica (Fabricius, 1792) (Coleoptera: Bostrychidae), Tribolium confusum Jaquelin Du Val, 1868 (Coleoptera: Tenebrionidae) adults at Stored Products Pest Laboratory of Plant Protection Central Research Institute (Ankara, Turkey) in 2020. A range of doses of Detech (100, 250 and 500 mg kg-1) and methyl eugenol (5, 10 and 15 mg kg-1) were used. To determine insect mortality, at a range of times after treatment, and half-doses of both products were also studied in order to examine simultaneous use for synergistic effect. The greatest effect of Detech on R. dominica , S. zeamais , S. granarius and T. confusum was observed with 500 mg kg-1 giving 81, 29, 26 and 18% mortality 28 d after treatment (DAT), respectively. Methyl eugenol at 15 mg kg-1 gave complete mortality with R. dominica adults 3 DAT. Simultaneous application of both products did not give complete mortality in test insects. The data show that Detech and methyl eugenol are promising treatments for the control of insect pests of stored products.

In package control of Rhyzopertha dominica in wheat using a continuous atmospheric jet cold plasma system

Cold plasma is recognized and explored for a plethora of applications in the food and agricultural industry. This study investigated the influence of a continuous atmospheric pressure non-thermal jet plasma system on the mortality of Rhyzopertha dominica adults in whole wheat kernels and the changes in the milling and physicochemical attributes of the treated whole wheat. Air-filled packets of whole wheat kernels were artificially infested with R. dominica adults. The packages were carried by a continuous conveyor belt and treated with plasma at voltages ranging from 44-47 kV for 4-7 min. The mortality was determined after 24 h and milling yield, particle size, proximate composition, and color of plasma-treated and untreated wheat grains were also evaluated. The maximum mortality was 88.33% at 47 kV for 7 min. The milling yield, protein, and fiber content of wheat were enhanced with plasma treatment significantly. Thus the continuous atmospheric pressure jet plasma used in this study could be one of the practically implementable emerging techniques for the commercial disinfestation of packaged food products.