RESUMEN
The granary weevil Sitophilus granarius (L.) is one of the most serious primary insect pests of stored products. When S. granarius present in grains, various volatile organic compounds are released as chemical signals which can be used to detect the insects. In this study, volatile chemical compounds released from S. granarius were analyzed using the headspace solid phase micro-extraction (HS-SPME) coupled with gas chromatography (GC)-mass spectrometry (MS) techniques. Two key compounds, 3-hydroxy-2-butanone and 1-pentadecene, were identified from mixed gender of S. granarius adults at high density. Moreover, both male and female adults showed dose-dependent electroantennography (EAG) responses to 3-hydroxy-2-butanone. In behavioral assays, S. granarius was attracted to 3-hydroxy-2-butanone at 0.001 µg/10 µL but repelled at 10 µg/10 µL or higher. S. granarius was consistently repelled by 1-pentadecene at concentrations at 0.001 and 1000 µg/10 µL. 3-hydroxy-2-butanone and 1-pentadecene have considerable potential to offer in the development of new approaches for the monitoring and management of this destructive stored grain insect pest.
RESUMEN
The attractiveness of ten commercially available Italian macaroni pastas made from different cereals [Triticum durum; Triticum durum (whole wheat); Triticum dicoccum; mixture of five cereals; Triticum turgidum; Triticum turanicum] or legumes (Cicer arietinum; Lens culinaris; Pisum sativum; Vicia faba) to Sitophilus granarius, was compared. S. granarius adults were more attracted to cereal pastas than legume pastas, but the differences in attractiveness were not always significant. Consistent with the results of behavioural bioassays, the mortality of adults over 20 days exposed to pasta samples was 100% with the legume pasta samples and only 8% with the T. turanicum pasta. GC-MS analysis of HS-SPME extracts from the different pasta samples highlighted marked qualitative and quantitative differences, with aliphatic aldehydes and aliphatic alcohols being the most abundant volatile components of cereal- and legume-pastas, respectively. In two-choice behavioural bioassays, insect attraction to a 1:1 combination of T. turanicum and C. arietinum pastas (80%) was even higher than that observed in T. turanicum pasta alone (64%) and in C. arietinum pasta alone (20%). This strongly suggested that the low attractiveness of legume pasta is mainly due to the lack of attractant stimuli rather than emission of repellent compounds.
RESUMEN
Sitophilus granarius (L.) is considered to be one of the major pests causing damage to cereal grain stored in silos and granaries. Using traditional methods (synthetic insecticides, mechanical, or physical methods) to control this pest is either ineffective or dangerous to people and nature. It is, therefore, necessary to develop new cultivars of cereals that will be distinguished by a high natural tolerance of the foraging by S. granarius. The aim of this study is expressed in the set research hypothesis, stating that the number of offspring of the grain weevil on stored wheat kernels can depend on the content of fatty acids in the kernels. Thus, the qualitative and quantitative composition of fatty acids was determined in kernels of 10 winter wheat cultivars, and the abundance of the beetle's offspring generation of S. granarius that developed on the wheat grain, as well as the mass of produced dust and loss in the mass of wheat grain were determined. By applying statistical analyses (GLM, ANOVA, Pearson's linear correlation coefficient, and analysis of redundancy), the presence and character of the dependence between the determined content of fatty acids in wheat grain and the factors describing the development of S. granarius were established. The research results indicate that fatty acids from the groups C 18:1 and C 20:1 probably play an important role as substances stimulating the increase in the number of the tested pest progeny. In contrast, fatty acids C 15:0, C 16:1, and C 18:3, which were determined in large amounts in the grain of wheat cultivars Speedway, KWS Livius, and Julius, can reduce the number of offspring of pest insect.
RESUMEN
In Pakistan, the control of stored-product insect pests mainly relies on the use of phosphine gas along with other control tactics. The aim of this study was to determine the level of phosphine resistance among ten differently located populations of the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), the granary weevil, Sitophilus granarius (L.) (Coleoptera: Curculionidae), the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) and the khapra beetle, Trogoderma granarium Everts (Coleoptera: Dermestidae). Laboratory-susceptible populations of all insect species were also considered in the experiments. Concentration-response bioassays were conducted for each species. All of the tested populations (10 out of 10) of each species were found to be resistant to phosphine, but varied in their level of resistance. Probit analysis estimated LC50 at 2.85, 1.90, 2.54 and 2.01 ppm for laboratory-susceptible populations of R. dominica, S. granarius, T. castaneum and T. granarium, respectively. Against R. dominica, the highest and lowest resistance levels were observed in the Rahim Yar Khan (LC50 at 360.90 ppm) and Rawalpindi (LC50 at 210.98 ppm) populations, respectively. These resistant populations were 126.67- and 74.02-fold more resistant than the laboratory population. The Multan and Lahore populations of S. granarius exhibited the maximum (LC50 at 122.81 ppm) and minimum (LC50 at 45.96 ppm) resistance levels, respectively, i.e., they were 64.63- and 24.18-fold more resistant than the laboratory population. The Layyah population of T. castaneum showed the maximum resistance level (LC50 at 305.89 ppm) while the lowest was observed in the Lahore population (LC50 at 186.52 ppm), corresponding to 120.42- and 73.43-fold more resistant than the laboratory population, respectively. Regarding T. granarium, the Layyah population showed the maximum resistance level (LC50 at 169.99 ppm) while the Lahore population showed the minimum resistance (LC50 at 74.50 ppm), i.e., they were 84.57- and 37.06-fold more resistant than the laboratory population, respectively. Overall, R. dominica presented the highest resistance level, followed by T. castaneum, T. granarium and S. granarius. The current study suggests that the application of phosphine may not be an adequate control strategy for the management of the above tested insect pests in Pakistan.
RESUMEN
Sitophilus granarius (L.) is an important pest of stored grain worldwide. In recent years, sustainable methods against it have received attention as grain stock protective means. Our aim was to obtain information about the efficacy of infrared irradiation (IR) against S. granarius in laboratory conditions. The change in adult-activity and median lethal dose (LD50) triggered by IR in S. granarius was examined. The insecticidal efficacy in the infested grains was also analyzed at 12, 24, 48, and 72h following exposure to IR (250W), and the progeny-production was assessed 45 days upon the treatment. Based on our findings, total mortality ensued in a grain stock of 50 g at 412 s and a for 100 g grain at 256 s. A significant increase in S. granarius mortality could be observed in the higher grain weight regime, which can be accounted for by the higher heat-absorbance of objects with higher weight. The activity of pests immediately after the beginning of IR increased and subsequently became moderated. The observation of activity-peak brought about by irradiation contribute to the optimization of chemical intervention. This treatment could provide an effective and sustainable technique in integrated pest management.
RESUMEN
Poor storage conditions provide favorable environment to stored grain pests for their growth. The bio-pesticides are the best alternatives to synthetic pesticides. Present study was conducted to compare toxicity of Rubus fruticosus and Valeriana jatamansi against granary weevil, Sitophilus granarius and subsequent changes in enzyme activity responsible for grain damage. In current research 5 g of R. fruticosus fruit and V. jatamansi rhizome powders were tested separately against S. granarius, in 50 g wheat whole grains for seven days in comparison with the control. The enzymatic activity of malate dehydrogenase and α-amylase was observed in the cellular extracts of S. granarius. The insects were crushed and homogenized in phosphate-buffer solution and centrifuged at 10000 rpm for 5 minutes. For the enzymatic measurement supernatant was tested; the spectrophotometer was adjusted at 340 nm. The reagents were mixed and incubated at 25 °C for five minutes. The cuvettes were placed in the experimental and reference sites of spectrophotometer and recorded the change in absorbance for 3-4 minutes. There was 5.60% and 14.92% reduction in the activity of malate dehydrogenase in R. fruticosus and V. jatamansi, treated insects, respectively. The alpha amylase enzyme activity was 6.82% reduced and 63.63% increase in R. fruticosus and V. jatamansi, treated insects, respectively. Present study addresses that both plant powders are effective against granary weevil by altering enzyme activities so both the plant powders can be used as bio-pesticides against the stored grains pests.
As más condições de armazenamento proporcionam um ambiente favorável às pragas armazenadas para o crescimento. Os biopesticidas são as melhores alternativas aos pesticidas sintéticos. O presente estudo foi conduzido para comparar a toxicidade de Rubus fruticosus e Valeriana jatamansi contra gorgulhos, Sitophilus granarius e subsequentes alterações na atividade enzimática responsáveis ââpor danos aos grãos. Na pesquisa atual, 5 g de frutos de R. fruticosus e pós de rizoma de V. jatamansi foram testados separadamente contra S. granarius, em 50 g de grãos integrais de trigo por sete dias, em comparação com o controle. A atividade enzimática da malato desidrogenase e α-amilase foi observada nos extratos celulares de S. granarius. Os insetos foram esmagados e homogeneizados em solução tampão fosfato e centrifugados a 10000 rpm por 5 minutos. Para a medição enzimática, o sobrenadante foi testado; o espectrofotômetro foi ajustado a 340 nm. Os reagentes foram misturados e incubados a 25 °C por cinco minutos. As cubetas foram colocadas nos locais experimentais e de referência do espectrofotômetro e registradas as alterações na absorbância por 3-4 minutos. Houve redução de 5,60% e 14,92% na atividade da malato desidrogenase em R. fruticosus e V. jatamansi, insetos tratados, respectivamente. A atividade da enzima alfa amilase foi reduzida em 6,82% e aumento de 63,63% em R. fruticosus e V. jatamansi, insetos tratados, respectivamente. O presente estudo aborda que ambos os pós de plantas são eficazes contra o gorgulho do celeiro, alterando as atividades enzimáticas, de modo que ambos os pós de plantas possam ser usados ââcomo biopesticidas contra pragas de grãos armazenados.
Asunto(s)
Animales , Valeriana/toxicidad , Gorgojos , Agentes de Control Biológico/administración & dosificación , Rubus/toxicidad , Control Biológico de Vectores/métodos , alfa-Amilasas , Almacenamiento de Alimentos/normas , Malato DeshidrogenasaRESUMEN
Abstract Poor storage conditions provide favorable environment to stored grain pests for their growth. The bio-pesticides are the best alternatives to synthetic pesticides. Present study was conducted to compare toxicity of Rubus fruticosus and Valeriana jatamansi against granary weevil, Sitophilus granarius and subsequent changes in enzyme activity responsible for grain damage. In current research 5 g of R. fruticosus fruit and V. jatamansi rhizome powders were tested separately against S. granarius, in 50 g wheat whole grains for seven days in comparison with the control. The enzymatic activity of malate dehydrogenase and -amylase was observed in the cellular extracts of S. granarius. The insects were crushed and homogenized in phosphate-buffer solution and centrifuged at 10000 rpm for 5 minutes. For the enzymatic measurement supernatant was tested; the spectrophotometer was adjusted at 340 nm. The reagents were mixed and incubated at 25 °C for five minutes. The cuvettes were placed in the experimental and reference sites of spectrophotometer and recorded the change in absorbance for 3-4 minutes. There was 5.60% and 14.92% reduction in the activity of malate dehydrogenase in R. fruticosus and V. jatamansi, treated insects, respectively. The alpha amylase enzyme activity was 6.82% reduced and 63.63% increase in R. fruticosus and V. jatamansi, treated insects, respectively. Present study addresses that both plant powders are effective against granary weevil by altering enzyme activities so both the plant powders can be used as bio-pesticides against the stored grains pests.
Resumo As más condições de armazenamento proporcionam um ambiente favorável às pragas armazenadas para o crescimento. Os biopesticidas são as melhores alternativas aos pesticidas sintéticos. O presente estudo foi conduzido para comparar a toxicidade de Rubus fruticosus e Valeriana jatamansi contra gorgulhos, Sitophilus granarius e subsequentes alterações na atividade enzimática responsáveis por danos aos grãos. Na pesquisa atual, 5 g de frutos de R. fruticosus e pós de rizoma de V. jatamansi foram testados separadamente contra S. granarius, em 50 g de grãos integrais de trigo por sete dias, em comparação com o controle. A atividade enzimática da malato desidrogenase e -amilase foi observada nos extratos celulares de S. granarius. Os insetos foram esmagados e homogeneizados em solução tampão fosfato e centrifugados a 10000 rpm por 5 minutos. Para a medição enzimática, o sobrenadante foi testado; o espectrofotômetro foi ajustado a 340 nm. Os reagentes foram misturados e incubados a 25 °C por cinco minutos. As cubetas foram colocadas nos locais experimentais e de referência do espectrofotômetro e registradas as alterações na absorbância por 3-4 minutos. Houve redução de 5,60% e 14,92% na atividade da malato desidrogenase em R. fruticosus e V. jatamansi, insetos tratados, respectivamente. A atividade da enzima alfa amilase foi reduzida em 6,82% e aumento de 63,63% em R. fruticosus e V. jatamansi, insetos tratados, respectivamente. O presente estudo aborda que ambos os pós de plantas são eficazes contra o gorgulho do celeiro, alterando as atividades enzimáticas, de modo que ambos os pós de plantas possam ser usados como biopesticidas contra pragas de grãos armazenados.