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Hermetic storage of dry soybean (Glycine max): creating an effective modified atmosphere using soaked grain as O2 depletor: Poster
Get PDFHermetic storage of grains and oilseed has been proposed as a solution for reducing food losses in developing countries. However, to obtain full benefit of the hermetic storage it is required to achieve a low O2 concentration (below 2%) or high CO2 concentration (above 20%). The gas concentration inside the hermetic container is the result of the balance between the respiration and gas exchange rates with the outside (permeability and leakage). When the grain is dry, an insufficient modification in the internal atmosphere is achieved (exchange rate higher than respiration rate), allowing insect development and, hence, grain losses. This study focuses in creating an effective modified atmosphere during the hermetic storage of dry soybean using soaked grain as O2 depletor. Three big bags with internal polyethylene liners of 70 µm thickness were filled with 590 kg of soybean (Glycine max, with 12.5% m.c.) and sealed. Gas concentration evolution was measured during 15 days (basal condition). Later, four plastic perforated bottles filled with of 4.3 kg of soaked soybean (44% m.c.) were inserted in each bag. The bags were re-sealed and gas concentration was measured during 45 days. Results indicated that the soaked soybean acted as an O2 depletor, reducing the gas concentration to 1% in only 8 days, and maintained below 1% during 45 days. This research indicated that a small portion of soaked grain (0.4% dry matter (d.m.)) can be used to generate an effective modified atmosphere to prevent biological activity in the entire grain mass. This is a simple and inexpensive approach to reduce food losses under low cost hermetic storage.Hermetic storage of grains and oilseed has been proposed as a solution for reducing food losses in developing countries. However, to obtain full benefit of the hermetic storage it is required to achieve a low O2 concentration (below 2%) or high CO2 concentration (above 20%). The gas concentration inside the hermetic container is the result of the balance between the respiration and gas exchange rates with the outside (permeability and leakage). When the grain is dry, an insufficient modification in the internal atmosphere is achieved (exchange rate higher than respiration rate), allowing insect development and, hence, grain losses. This study focuses in creating an effective modified atmosphere during the hermetic storage of dry soybean using soaked grain as O2 depletor. Three big bags with internal polyethylene liners of 70 µm thickness were filled with 590 kg of soybean (Glycine max, with 12.5% m.c.) and sealed. Gas concentration evolution was measured during 15 days (basal condition). Later, four plastic perforated bottles filled with of 4.3 kg of soaked soybean (44% m.c.) were inserted in each bag. The bags were re-sealed and gas concentration was measured during 45 days. Results indicated that the soaked soybean acted as an O2 depletor, reducing the gas concentration to 1% in only 8 days, and maintained below 1% during 45 days. This research indicated that a small portion of soaked grain (0.4% dry matter (d.m.)) can be used to generate an effective modified atmosphere to prevent biological activity in the entire grain mass. This is a simple and inexpensive approach to reduce food losses under low cost hermetic storage
Efficiency of ozone gas treatment against Plodia interpunctella (Hübner) (Lepidoptera:Pyralidae) (Indianmeal Moth) in hazelnut: Poster
Get PDFIn this study, ozone gas at different concentrations (16.7, 33.3 and 66.6 mg/L) were exposed to all biological stages (egg, larva, pupa and adult) placed at top and bottom of the hazelnut for various exposure periods (2, 4 and 6 hours). In biological tests conducted in presence of hazelnuts, 100% mortalities of all biological stages of P. interpunctella placed at top of the commodity were obtained at tested ozone concentrations and exposure periods while it was easier to kill the adult and pupa stages that the larva and egg stages. While it was possible to kill 100% of the adults and pupae placed at bottom of the commodity at tested ozone concentrations and exposure periods, 100% mortality of the larvae and eggs were not obtained at any of the ozone treatments. Generally, the mortalities of all life stages of P. interpunctella placed at bottom of the commodity for ozone treatments were lower than those placed at top of the commodity. It was easy to kill the pupae and adults of P. interpunctella placed at bottom of the commodity while the ozone treatments resulted in low mortalities of the egg and larvae placed at bottom of the commodity. Just as 100% mortalities of the larva and adult stages were not obtained even at the highest ozone concentration for the longest exposure period. In conclusion, in this study, it was observed that ozone gas only at high concentrations can control all biological stages of P. interpunctella in hazelnut and therefore could have an alternative potential for methyl bromide in quarantine applications in short application period.In this study, ozone gas at different concentrations (16.7, 33.3 and 66.6 mg/L) were exposed to all biological stages (egg, larva, pupa and adult) placed at top and bottom of the hazelnut for various exposure periods (2, 4 and 6 hours). In biological tests conducted in presence of hazelnuts, 100% mortalities of all biological stages of P. interpunctella placed at top of the commodity were obtained at tested ozone concentrations and exposure periods while it was easier to kill the adult and pupa stages that the larva and egg stages. While it was possible to kill 100% of the adults and pupae placed at bottom of the commodity at tested ozone concentrations and exposure periods, 100% mortality of the larvae and eggs were not obtained at any of the ozone treatments. Generally, the mortalities of all life stages of P. interpunctella placed at bottom of the commodity for ozone treatments were lower than those placed at top of the commodity. It was easy to kill the pupae and adults of P. interpunctella placed at bottom of the commodity while the ozone treatments resulted in low mortalities of the egg and larvae placed at bottom of the commodity. Just as 100% mortalities of the larva and adult stages were not obtained even at the highest ozone concentration for the longest exposure period. In conclusion, in this study, it was observed that ozone gas only at high concentrations can control all biological stages of P. interpunctella in hazelnut and therefore could have an alternative potential for methyl bromide in quarantine applications in short application period
Supporting quarantine and health & safety monitoring of fumigants and industrial chemicals in offshore transport containers with Gasmet Multicomponent FTIR gas detection technology: Poster
Get PDFModeling the distribution of phosphine in cylindrical grain silos with CFD methods for precision fumigation: Poster
Get PDFIn the present study, the distribution of phosphine gas in a cylindrical silo was modeled and compared with available sensor data. The cylindrical silo was filled with wheat and a recirculation system was used to enhance the diffusion of phosphine throughout the grain volume. A Computational Fluid Dynamics (CFD) model was developed with OpenFoam software, which accounted for gas transport in porous media and sorption effects of phosphine into the grain. A time-dependent source was used to model the phosphine release from Aluminum Phosphide bags. Furthermore, simulation results were obtained for insect mortality as a function of their exposure to phosphine gas. The phosphine concentration measurements were available from calibrated wireless sensors provided by Centaur Analytics, placed near the silo walls at various heights. As the agreement of phosphine measured data with the simulation results was satisfying, it led to considering that the proposed CFD model (equations, boundary conditions, grain properties, recirculation system approach, etc.) was accurate. Utilizing the capabilities of fumigation modeling, the phosphine concentration could then be determined for every location inside the storage volume and at any given time, thus a prediction method for fumigation duration and success could be enabled. Additionally, as the CFD model correlates phosphine exposure with insect mortality, a methodology for planning precision fumigations can now be established.In the present study, the distribution of phosphine gas in a cylindrical silo was modeled and compared with available sensor data. The cylindrical silo was filled with wheat and a recirculation system was used to enhance the diffusion of phosphine throughout the grain volume. A Computational Fluid Dynamics (CFD) model was developed with OpenFoam software, which accounted for gas transport in porous media and sorption effects of phosphine into the grain. A time-dependent source was used to model the phosphine release from Aluminum Phosphide bags. Furthermore, simulation results were obtained for insect mortality as a function of their exposure to phosphine gas. The phosphine concentration measurements were available from calibrated wireless sensors provided by Centaur Analytics, placed near the silo walls at various heights. As the agreement of phosphine measured data with the simulation results was satisfying, it led to considering that the proposed CFD model (equations, boundary conditions, grain properties, recirculation system approach, etc.) was accurate. Utilizing the capabilities of fumigation modeling, the phosphine concentration could then be determined for every location inside the storage volume and at any given time, thus a prediction method for fumigation duration and success could be enabled. Additionally, as the CFD model correlates phosphine exposure with insect mortality, a methodology for planning precision fumigations can now be established
Dates fumigation with phosphine: Poster
Get PDFStored dates are usually infested by sap beetles and moths. For years, the common practice for dates disinfestation was fumigation with methyl bromide (MB). After MB phase-out, heat treatment and modified atmosphere are used. However, there are several limitations of these methods. In search for alternatives for dates disinfestation, fumigation by phosphine was evaluated. Commercial fumigations of Medjool dates variety using phosphine were conducted in a standard 20 ft. shipping container. Two formulations of phosphine were used: Magtoxin® Plates 56% (Detia Freyberg GmbH, Germany), and Phostoxin® Tablets 56% (Detia Freyberg GmbH, Germany). The phosphine dosage range was 1-4 g/m3. The exposure time range was 24-72 hrs. Several fumigations were carried out by an innovative phosphine generator model OMT 501 developed by Universal Probes. Most fumigations carried out demonstrated total dates disinfestation. The application of Magtoxin plates, especially using the OMT 501 demonstrates significant advantages versus Phostoxin tablets; the advantages were in quicker gas development, and achieving much higher maximum and pre-ventilation phosphine concentration levels. Upon fumigation using the OMT 501, plates are easily collected and disposed, no residual dust left on the dates, which avoided their contamination. No phosphine residues were found in the fumigated dates, neither changes in organoleptic properties were noted. Phosphine fumigation using the phosphine generator model OMT 501 provides safer, quicker, more efficient dates disinfestation.Stored dates are usually infested by sap beetles and moths. For years, the common practice for dates disinfestation was fumigation with methyl bromide (MB). After MB phase-out, heat treatment and modified atmosphere are used. However, there are several limitations of these methods. In search for alternatives for dates disinfestation, fumigation by phosphine was evaluated. Commercial fumigations of Medjool dates variety using phosphine were conducted in a standard 20 ft. shipping container. Two formulations of phosphine were used: Magtoxin® Plates 56% (Detia Freyberg GmbH, Germany), and Phostoxin® Tablets 56% (Detia Freyberg GmbH, Germany). The phosphine dosage range was 1-4 g/m3. The exposure time range was 24-72 hrs. Several fumigations were carried out by an innovative phosphine generator model OMT 501 developed by Universal Probes. Most fumigations carried out demonstrated total dates disinfestation. The application of Magtoxin plates, especially using the OMT 501 demonstrates significant advantages versus Phostoxin tablets; the advantages were in quicker gas development, and achieving much higher maximum and pre-ventilation phosphine concentration levels. Upon fumigation using the OMT 501, plates are easily collected and disposed, no residual dust left on the dates, which avoided their contamination. No phosphine residues were found in the fumigated dates, neither changes in organoleptic properties were noted. Phosphine fumigation using the phosphine generator model OMT 501 provides safer, quicker, more efficient dates disinfestation
Laboratory evaluation of Turkish diatomaceous earths as potential stored grain protectants: Presentation
No full textIn this study, efficacy of local diatomaceous earths (DE) collected from different regions of Turkey against stored grain insects, Sitophilus oryzae (L.), Tribolium confusum du Val. and Rhyzopertha dominica (F.), was investigated. For this purpose, biological tests were carried out at concentrations of 500 and 1000 ppm (mg DE / kg wheat) of 9 local diatomaceous earths and one commercial diatomaceous earth, namely Silicosec® as positive control at 25 ± 1 ° C temperature and 65 ± 5% relative humidity in wheat. In addition, the studies on some of the chemical and physical analysis of the tested diatomaceous earths (silicon dioxide (SiO2) ratio, particle size and adhesion rate on commodity) were also conducted. In biological tests conducted at 500 ppm concentration for 14 days of exposure in wheat the highest mortality rates (97 to 98%) of S. oryzae adults were recorded in CB2N-1, AGN-1 and BGN-1 diatomaceous earths, while the highest mortality rates of T. confusum adults were obtained from only AGN-1 and BGN-1 diatomaceous earths. In the case of R. dominica, the highest mortality rate (64.4%) was recorded only in CB2N-1 diatomaceous earth. At concentration of 1000 ppm for 14 days of exposure in wheat, 100% mortality of S. oryzae adults was observed in all tested local diatomaceous earths except FB2N-1 and Silicosec® while mortality rates of T. confusum adults ranging from % 95 to %100 were obtained in all tested local diatomaceous earths except FB2N-1, FBN-1 and Silicosec®. In the case of R. dominica adults, mortality rates ranging from 80% to 93% were recorded in CB2N-1, CCN-1 and AG2N-1 diatomaceous earths. In conclusion, laboratory bioassays indicated that CB2N-1 and BGN-1 local diatomaceous earths had high efficacy against S. oryzae, T. confusum and R. dominica adults and thus could be potential to be successfully used for controlling stored grain insect pests as a grain protectant.In this study, efficacy of local diatomaceous earths (DE) collected from different regions of Turkey against stored grain insects, Sitophilus oryzae (L.), Tribolium confusum du Val. and Rhyzopertha dominica (F.), was investigated. For this purpose, biological tests were carried out at concentrations of 500 and 1000 ppm (mg DE / kg wheat) of 9 local diatomaceous earths and one commercial diatomaceous earth, namely Silicosec® as positive control at 25 ± 1 ° C temperature and 65 ± 5% relative humidity in wheat. In addition, the studies on some of the chemical and physical analysis of the tested diatomaceous earths (silicon dioxide (SiO2) ratio, particle size and adhesion rate on commodity) were also conducted. In biological tests conducted at 500 ppm concentration for 14 days of exposure in wheat the highest mortality rates (97 to 98%) of S. oryzae adults were recorded in CB2N-1, AGN-1 and BGN-1 diatomaceous earths, while the highest mortality rates of T. confusum adults were obtained from only AGN-1 and BGN-1 diatomaceous earths. In the case of R. dominica, the highest mortality rate (64.4%) was recorded only in CB2N-1 diatomaceous earth. At concentration of 1000 ppm for 14 days of exposure in wheat, 100% mortality of S. oryzae adults was observed in all tested local diatomaceous earths except FB2N-1 and Silicosec® while mortality rates of T. confusum adults ranging from % 95 to %100 were obtained in all tested local diatomaceous earths except FB2N-1, FBN-1 and Silicosec®. In the case of R. dominica adults, mortality rates ranging from 80% to 93% were recorded in CB2N-1, CCN-1 and AG2N-1 diatomaceous earths. In conclusion, laboratory bioassays indicated that CB2N-1 and BGN-1 local diatomaceous earths had high efficacy against S. oryzae, T. confusum and R. dominica adults and thus could be potential to be successfully used for controlling stored grain insect pests as a grain protectant
Efficacy of seven Turkish diatomaceous earths against Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchninae) on stored chickpea: Presentation
Get PDFIn this study, insecticidal efficacy of seven different local diatomaceous earths (DE) obtained from different deposits in Turkey together with two commercial DEs, Silicosec® (Biofa AG- Germany) and Desect® (Ep Naturals- America) against Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchninae) an important pest of stored chickpea at five different concentrations (100, 300, 500, 1000 and 1500 ppm) was evaluated. The local DEs were coded as BGN, BHN, AG2N, AC2N, CB2N, CCN, FB2N. Mortality of the adults was assessed after 1, 3, 5 and 7 days of exposure, and consequently progeny (F1) production on treated chickpeas was recorded 42 days later. The tests were carried out under laboratory conditions of 25±1 °C, 55±5 % R.H. in a dark place. The most effective DEs after 1 day of exposure were CCN, AG2N and BHN causing 75%, 59%, 58% mortalities, respectively at 1500 ppm concentration. Silicosec®, Desect®, BGN, AC2N, applied at 1500 ppm concentration achieved 98-100% mortality of C.maculatus after 7 days of exposure, showing similar high insecticidal efficacy. The CCN, BHN, AG2N and CB2N caused 97-99% reduction in progeny (F1) production. Generally, increasing concentration significantly reduced the progeny production. In conclusion, this study has shown that three Turkish DEs, namelyCCN, AG2N and BHN highly toxic to C. maculatus after 3 days of exposurein comparison with commercial DEs Silicosec® and Desect®. These local DEs could be used in the management of pests of stored chickpea.In this study, insecticidal efficacy of seven different local diatomaceous earths (DE) obtained from different deposits in Turkey together with two commercial DEs, Silicosec® (Biofa AG- Germany) and Desect® (Ep Naturals- America) against Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchninae) an important pest of stored chickpea at five different concentrations (100, 300, 500, 1000 and 1500 ppm) was evaluated. The local DEs were coded as BGN, BHN, AG2N, AC2N, CB2N, CCN, FB2N. Mortality of the adults was assessed after 1, 3, 5 and 7 days of exposure, and consequently progeny (F1) production on treated chickpeas was recorded 42 days later. The tests were carried out under laboratory conditions of 25±1 °C, 55±5 % R.H. in a dark place. The most effective DEs after 1 day of exposure were CCN, AG2N and BHN causing 75%, 59%, 58% mortalities, respectively at 1500 ppm concentration. Silicosec®, Desect®, BGN, AC2N, applied at 1500 ppm concentration achieved 98-100% mortality of C.maculatus after 7 days of exposure, showing similar high insecticidal efficacy. The CCN, BHN, AG2N and CB2N caused 97-99% reduction in progeny (F1) production. Generally, increasing concentration significantly reduced the progeny production. In conclusion, this study has shown that three Turkish DEs, namelyCCN, AG2N and BHN highly toxic to C. maculatus after 3 days of exposurein comparison with commercial DEs Silicosec® and Desect®. These local DEs could be used in the management of pests of stored chickpea
Fogging loads of California fresh citrus for control of Asian citrus psyllid, Diaphorina citri: Presentation
No full textContact insecticides are commonly applied as fogs to disinfest and disinfect spaces. Recently, these fogs have been adapted to treat commodity within the spaces, and much has been learned regarding the efficacy of this process. When considering fresh citrus in California, fogs are applied to control both insects and microbes. One insect pest, the Asian citrus psyllid (ACP), Diaphorina citri, is a quarantine pest in California and limiting its geographic distribution is a major goal of the California citrus industry. While a variety of phytosanitary measures can be used to control adult ACP once fruit is at a packing house, ultimately, a treatment must be developed to disinfest field-run fruit prior to its exiting the grove. High-pressure fogging with 1,100-L of an aqueous mixture containing 0.2% Evergreen® (6% pyrethrins & 60% piperonyl butoxide) and 0.5% (v/v) BreakThru® (polysiloxane surfactant) was explored in laboratory-, pilot-, and commercial-scale trials as an approach to disinfest a 48-bin trailer load of fresh citrus. Laboratory-scale studies were conducted to quantify, and subsequently model, insecticidal coverage as a function of temperature, surface area, droplet size, and fog volume. Results are discussed in the context of experimental variability across confirmatory trials and continued efforts to optimize the technical and economic feasibility of fogging as a postharvest control strategy.Contact insecticides are commonly applied as fogs to disinfest and disinfect spaces. Recently, these fogs have been adapted to treat commodity within the spaces, and much has been learned regarding the efficacy of this process. When considering fresh citrus in California, fogs are applied to control both insects and microbes. One insect pest, the Asian citrus psyllid (ACP), Diaphorina citri, is a quarantine pest in California and limiting its geographic distribution is a major goal of the California citrus industry. While a variety of phytosanitary measures can be used to control adult ACP once fruit is at a packing house, ultimately, a treatment must be developed to disinfest field-run fruit prior to its exiting the grove. High-pressure fogging with 1,100-L of an aqueous mixture containing 0.2% Evergreen® (6% pyrethrins & 60% piperonyl butoxide) and 0.5% (v/v) BreakThru® (polysiloxane surfactant) was explored in laboratory-, pilot-, and commercial-scale trials as an approach to disinfest a 48-bin trailer load of fresh citrus. Laboratory-scale studies were conducted to quantify, and subsequently model, insecticidal coverage as a function of temperature, surface area, droplet size, and fog volume. Results are discussed in the context of experimental variability across confirmatory trials and continued efforts to optimize the technical and economic feasibility of fogging as a postharvest control strategy
Entomocidal, repellent, antifeedent and growth nhibition efects of different plant extracts against Tribolium castaneum (Herbst) (Tenebrionidae: Coleoptera): Poster
No full textIn present investigation, toxic, repellent, antifeedent and growth inhibition effects of five different plant extracts: Melia azedarach, Pegnum hermala, Salsola baryosma, Azadirachta indica and Zingiber officinale, were evaluated on different life stages of T. castaneum. The highest mortality (10.14%) was observed with A. indica and the minimum mortality (0.67%) was invoked by Z. officinale treatment. Similarly, A. indica showed highest repellent effect compared to rest of the plants. Feeding deterrence was highest (90.15%) with S. baryosma treatment, followed by P. hermala (84.85%), M. azedarach (80.19%), A. indica (73.48%) and Z. officinale (57.58%). The extracts inhibited the growth of T. castaneum. Inthe case of A. indica, the lowest numbers of larvae (32.67), pupae (16.33) and adults (11.33) emerged at 15% concentration, while the highest emergence of larvae (80.33), pupae (75.00) and adult (71.00) were observed for Z. officinale. The other three plant extracts had moderate regrowth inhibition on the beetle. Overall, A. indica extract was found to be the most effective while, Z. officinale extract was least effective against the beetle. This study can be very helpful in future when the use of plant extracts become common and available to the farmers as an alternative to synthetic pesticides.In present investigation, toxic, repellent, antifeedent and growth inhibition effects of five different plant extracts: Melia azedarach, Pegnum hermala, Salsola baryosma, Azadirachta indica and Zingiber officinale, were evaluated on different life stages of T. castaneum. The highest mortality (10.14%) was observed with A. indica and the minimum mortality (0.67%) was invoked by Z. officinale treatment. Similarly, A. indica showed highest repellent effect compared to rest of the plants. Feeding deterrence was highest (90.15%) with S. baryosma treatment, followed by P. hermala (84.85%), M. azedarach (80.19%), A. indica (73.48%) and Z. officinale (57.58%). The extracts inhibited the growth of T. castaneum. Inthe case of A. indica, the lowest numbers of larvae (32.67), pupae (16.33) and adults (11.33) emerged at 15% concentration, while the highest emergence of larvae (80.33), pupae (75.00) and adult (71.00) were observed for Z. officinale. The other three plant extracts had moderate regrowth inhibition on the beetle. Overall, A. indica extract was found to be the most effective while, Z. officinale extract was least effective against the beetle. This study can be very helpful in future when the use of plant extracts become common and available to the farmers as an alternative to synthetic pesticides
Effects of chlorpyrifos-methyl and pirimiphos-methyl applied with 5°C temperature on Sitophilus oryzae (L.) (Coleoptera: Curculionidae) in wheat grain: Poster
No full textThe effects of the insecticides chlorpyrifos-methyl and pirimiphos-methyl in combination with low temperature treatment at 5°C were tested in the laboratory to improve the existing pest management programs for S. oryzae control. Adults were released into wheat grain pretreated with three insecticide doses: 0.08, 0.12 and 0.16 mg/kg of chlorpyrifos-methyl, and 0.125, 0.19 and 0.25 mg/kg of pirimiphos-methyl, and exposed to 5°C temperature over intervals of 5, 6, 7 and 8 days. Mortality after low temperature only, insecticides only, and their combinations, was assessed after 1, 2, 7 and 14 days of recovery at 25±1°C and 60±5% r.h., as well as their impact on F1 progeny production/reduction (PR) after 8 weeks. The combined application of 0.16 mg/kg chlorpyrifosmethyl and 5°C temperature (5-7 days of exposure) caused a significantly higher mortality of S. oryzae after 1, 2, 7 and 14 days of recovery than the activity of low temperature alone, as well as the combined application of 0.12 mg/kg chlorpyrifos-methyl and 5°C after 7 and 14 days of recovery. Adults mortality and progeny reduction of S. oryzae was =92% after 14 days of recovery from an interaction of 0.16 mg/kg dose of chlorpyrifos-methyl and exposure for 6 days to 5°C, as well as all doses in combination with 7 days exposure to 5°C. Combined application of 0.25 mg/kg pirimiphos-methyl and 5, 6 and 7 days of exposure to 5°C caused a significantly higher mortality of S. oryzae after 7, 2 and 1 day of recovery, respectively, compared to temperature-only exposure. High mortality (91-95%) and progeny reduction >92% were caused by the same pirimiphos-methyl rate in combination with 6 and 7 days of exposure to 5°C after 7 days of recovery as the combination of 5, 6 and 7 days of exposure to 5°C after 14 days of recovery.The effects of the insecticides chlorpyrifos-methyl and pirimiphos-methyl in combination with low temperature treatment at 5°C were tested in the laboratory to improve the existing pest management programs for S. oryzae control. Adults were released into wheat grain pretreated with three insecticide doses: 0.08, 0.12 and 0.16 mg/kg of chlorpyrifos-methyl, and 0.125, 0.19 and 0.25 mg/kg of pirimiphos-methyl, and exposed to 5°C temperature over intervals of 5, 6, 7 and 8 days. Mortality after low temperature only, insecticides only, and their combinations, was assessed after 1, 2, 7 and 14 days of recovery at 25±1°C and 60±5% r.h., as well as their impact on F1 progeny production/reduction (PR) after 8 weeks. The combined application of 0.16 mg/kg chlorpyrifosmethyl and 5°C temperature (5-7 days of exposure) caused a significantly higher mortality of S. oryzae after 1, 2, 7 and 14 days of recovery than the activity of low temperature alone, as well as the combined application of 0.12 mg/kg chlorpyrifos-methyl and 5°C after 7 and 14 days of recovery. Adults mortality and progeny reduction of S. oryzae was =92% after 14 days of recovery from an interaction of 0.16 mg/kg dose of chlorpyrifos-methyl and exposure for 6 days to 5°C, as well as all doses in combination with 7 days exposure to 5°C. Combined application of 0.25 mg/kg pirimiphos-methyl and 5, 6 and 7 days of exposure to 5°C caused a significantly higher mortality of S. oryzae after 7, 2 and 1 day of recovery, respectively, compared to temperature-only exposure. High mortality (91-95%) and progeny reduction >92% were caused by the same pirimiphos-methyl rate in combination with 6 and 7 days of exposure to 5°C after 7 days of recovery as the combination of 5, 6 and 7 days of exposure to 5°C after 14 days of recovery