Effect of60Co gamma radiation on the rice weevil,Sitophilus oryzae (L.)

The effect of gramma radiation on the rice weevil,Sitophilus oryzae (L.) was studied. Adults were subjected to 12 doses ranging from 0 to 180 Gy of gamma radiation from a⁶⁰Co source. The time to onset of death and the duration of the period of mortality were investigated. Survival of the adults was decreased with increase of the doses. LD₅₀ and LD_99,9 values were calculated.With one figure and one table     

Initial and residual efficacy of insecticides on different surfaces against rice weevil Sitophilus oryzae (L.)

The aim of the study was to investigate how various types of storage facilities with, e.g., concrete, metal, and plywood surfaces interfere with the activity of different insecticide formulations used for rice weevil Sitophilus oryzae (L.) control: malathion (EC), pirimiphos-methyl (EC), and lambda-cyhalothrin (CS and WP). Initial and residual efficacy were determined in the laboratory. Knockdown data for the initial effects were processed by probit analysis and presented as knockdown time (KDT) parameters with kdt-p lines. Delayed effects were shown as knockdown efficacy (%) determined after 24 h of weevils’ contact with 7-, 14-, 30-, 60-, 90-, 120-, 150-, and 180-day-old deposits on each surface. Malathion (EC) and pirimiphos-methyl (EC) showed the highest initial knockdown efficacy on metal, while it was 3.6 (3.4)- and 4.4 (3.3)-fold lower on concrete and plywood, respectively. Lambda-cyhalothrin (CS and WP) showed the highest initial efficacy on concrete, and slightly lower (1.3 and 2.4) fold on metal and plywood, respectively. Both formulations of lambda-cyhalothrin and malathion on metal, as well as pirimiphos-methyl on plywood were 100 % efficient against S. oryzae 180 days after the treatment. Delayed efficacy of both formulations of lambda-cyhalothrin decreased on plywood after 120 days, and after 180 days the efficacy was 55 %. All insecticides, except lambda-cyhalothrin (CS), expressed low knockdown efficacy on concrete, while the deposit of lambda-cyhalothrin (CS) on concrete was 100 % efficient during 90 days, and after 120, 150, and 180 days the efficacy was 83, 65, and 17 %, respectively.     

The effect of carbon dioxide under pressure against eggs of Ephestia kuehniella Zeller and adults of Stegobium paniceum (L.) and Oryzaephilus surinamensis (L.)

The efficacy of an atmosphere with a high content of carbon dioxide under a pressure of 5 and 10 bar against young eggs of Ephestia kuehniella Zeller (Lep.: Pyralidae) and adults of Stegobium paniceum (L.) (Col.: Anobiidae) and Oryzaephilus surinamensis (L.) (Col.: Cucujidae) was investigated. At a pressure level of 10 bar, a 100?% mortality in eggs of E. kuehniella was obtained after 4 hours. Complete control was not obtained with the adult beetles, except for a 2 hour-treatment at 10 bar with individuals of S. paniceum, which not were offered protection. It is demonstrated that when working with an atmosphere of carbon dioxide under pressure of 10 bar for 2 hours, even a slight protection from food material will influence the mortality. The reason for these findings are discussed.     

The effects of cold pre-treatment on the toxicity of several contact insecticides on adults of three Sitophilus granarius (L.) populations

As very little is known about the impact of cold pre-treatments on insecticidal toxicity to the surviving stored-product insects, we examined the effects of cooling (?5 °C) on the toxicity of five contact insecticides to Sitophilus granarius adults from three populations (laboratory, field and selected). We determined: (a) weevil lethal time after exposure to ?5 °C, (b) the effects of two cold pre-treatments (LT₂₀ and LT₅₀—lethal time for 20 and 50 % of exposed adults) on 24 and 72 h recovery rates of laboratory adults after exposure to five insecticides and (c) deltamethrin, dichlorvos and malathion toxicity to two weevil populations with altered insecticide susceptibility after exposure to the LT₂₀ and LT₅₀ pre-treatments. The tested S. granarius populations showed no significant differences in their susceptibility to cooling. All insecticides except dichlorvos were more toxic to the laboratory weevils after 24 h than after 72 h recovery from the LT₂₀ pre-treatment. Dichlorvos and deltamethrin were more toxic to the other two populations after 72 h of recovery. Comparing the effects of cold pre-treatment and non-treatment on the laboratory strain, no significant increase in the toxicity of insecticides was detected, while only deltamethrin was significantly more toxic to the field and selected populations recovering for 24 h (12.1 and 11.0 times, respectively) and 72 h (6.9 and 36.6 times) from the LT₂₀ pre-treatment. In conclusion, only the shorter of the two cold pre-treatments was found effective in terms of increasing the insecticidal toxicity, especially against the populations with altered susceptibility to insecticides.     

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

Diatomaceous 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.     

The effects of propagation environment on the rooting of leafy cuttings of ash (Fraxinus excelsior L.), sycamore (Acer pseudoplatanus L.), and sweet chestnut (Castanea sativa Mill.)

The effect of propagation environment on the rooting of field collected leafy cuttings of ash (Fraxinus excelsior, sycamore (Acer pseudoplatanus) and sweet chestnut (Castanea sativa) was investigated in two experiments. In the first experiment, rooting of all three species in mist enclosed inside a polythene tent was greater than 50%, while rooting of ash cuttings was reduced from 63% in enclosed mist to only 16% in open mist. Rooting in open mist, enclosed mist, and contact polythene was studied in a second experiment. Sycamore cuttings rooted equally well in the two mist systems with an average rooting of 78%. In contrast cuttings of both ash and sweet chestnut rooted most under the enclosed mist system, at 64 and 46% respectively. Rooting of ash cuttings was again depressed in the open mist system where less than 30% of cuttings rooted. This reduction was related to an increase in the percentage of cuttings which remained alive without rooting, while showing proliferation of callus at the cutting base. The percentage of sweet chestnut cuttings which callused without rooting was also much greater in the open mist system than in enclosed mist or contact polythene.     

Investigation into the antioxidant activity and chemical composition of alcoholic extracts from defatted marigold (Tagetes erecta L.) residue

The influence of various solvents on the yield of polyphenols from defatted marigold residue, the antioxidant activity of the extracts and the composition of antioxidant compounds in the extracts were investigated. The content of total phenolics and flavonoids in the extracts was significantly varied with different solvents (P<0.05) and the extract by ethyl alcohol (EtOH)/water (7:3, v/v) has the highest content of total phenolics and flavonoids, 62.33 mg gallic acid equivalents (GAE)/g and 97.00 mg rutin equivalent (RE)/g, respectively. The antioxidant activity of the extracts was evaluated by radical (2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH)) scavenging and ferric reducing antioxidant power (FRAP) assays. The results of the correlation analysis showed that the antioxidant activity was well correlated with the content of total phenolics and flavonoids (R2>0.900). Antioxidant components in the extracts were identified by combined on-line HPLC-ABTS·+ post-column assay and HPLC-DAD-MS method. Gallic acid, gallicin, quercetagetin, 6-hydroxykaempferol-O-hexoside, patuletin-O-hexoside and quercetin were the dominant antioxidant compounds in the extracts, and quercetagetin was identified as the strongest antioxidant capacity.     

Impact of geochemical composition of diatomaceous earth on its insecticidal activity against adults of <Emphasis Type="Italic">Sitophilus oryzae</Emphasis> (L.) (Coleoptera: Curculionidae)

Laboratory experiments were done to determine the effect of geochemical composition of diatomaceous earth (DE) on insecticidal activity of DE against adults of the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae). Samples of DE were mined from DE-deposits in Slovenia, Greece, and Serbia. In addition, a commercially available DE formulation (SilicoSec^®) was used in the tests and served as a positive control. The bioassays were carried out at temperatures 20, 25, and 30°C, relative humidity levels of 55 and 75%, and at application rates of 100, 300, 500, and 900 ppm. Adult mortality was recorded after 7, 14, and 21 days of exposure. Prior to bioassays with S. oryzae, the geochemical composition of all DEs that were used in the tests was determined by whole rock ICP geochemical analyses. Silica (in the form of SiO₂ or opal-A) was the DE ingredient that was significantly correlated with efficacy in most of the bioassays. Some weak positive correlation was observed between S. oryzae mortality and MnO or CaO content. All significant correlations between mortality and Al₂O₃, Fe₂O_3, K₂O, TiO₂, Cr₂O₃, P₂O₅, and MgO content were negative, while correlation between Na₂O content and mortality was generally not significant.     

Bioactivity of some formulations of neem seed extracts against the whiteflyBemisia tabaci (Genn.)

The bioactivity of different formulations of neem seed extracts against the whiteflyBemisia tabaci (Genn.) was assayed in semifield trials during 1992. Tomato plants variety UC-97 were cultivated in pots and left to natural infestation with whitefly in an open field and sprayed with various concentrations of each extract. The high concentrations of all the extracts tested exhibited obvious activity. Also, the different treatments reduced the population density of the adult whiteflies compared with the control. The percentage reduction in the population reached its maximum level one hour after treatment with any tested extract.With one table     

Parasitoids of Saperda populnea (L.) (Coleoptera: Cerambycidae) on aspen (Populus tremula L.) in Bulgaria

The parasitoids of Saperda populnea (L.) (Col.: Cerambycidae) were studied in Bulgaria during the period 1997?–?2001. Galls with pest larvae were collected from young aspen trees at eight locations (Sofia, Kokaliane, Plana, Churek, Gorni Lom, Gintzi, Dolno Kamartzi and Klisura) and examined under laboratory conditions. Four species were reared from 1118 galls containing overwintering pest larvae: Iphiaulax impostor (Scop.) (Hym.: Braconidae), Dolichomitus populneus (Ratz.), Schreineria populnea (Gir.) (Hym.: Ichneumonidae) and Billaea irrorata (Meig.) (Dipt.: Tachinidae). All of the parasitoids were solitary. Schreineria populnea was found as a new parasitoid of the host in Bulgaria. B. irrorata emerged mainly from late-stage S. populnea larvae; the remaining species from both early- and mid-stage larvae. In the parasitoid complex of S. populnea, the most numerous were B. irrorata (59.8?%) and D. populneus (29.4?%). The percentage of host larval parasitism varied from 2.4 to 33.3, with an average of 9.7?%. B. irrorata was the most important in reducing the pest number. The average mortality of S. populnea caused by the tachinid was 5.8?%, and the highest mortality observed in individual study was 20.2?%.     

Superoxide dismutase (SOD) activity in Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies L. Karst.) needles in northern Finland

The superoxide dismutase (SOD EC 1.15.1.1) activity in Scots pine (Pinus sylvestris) and Norway spruce (Picea abies L. Karst.) needles in urban and rural trees of northern Finnish populations was studied. Enzyme activity was higher in pine than in spruce needles. Two pine clones from eastern Finland and Lapland revealed great differences in specific SOD enzyme activity.     

Effects of temperature and yeast supplementation on the development ofTribolium castaneum (Herbst) in wholemeal and polished flour derived from four cereals in Maiduguri, Nigeria

The effects of temperature, yeast and polishing (removal of bran) on the development ofTribolium castaneurn (Herbst) in flour derived from millet, sorghum, maize and wheat were investigated for one generation in Maiduguri, Nigeria. Significantly moreT. castaneurn adults and larvae developed in flour stored at 35 °C than in flour stored at 30 °C or 40 °C; mortality of adult beetles in flour stored at 40 °C was 95 % in sorghum and maize and 100 % in millet and wheat. Addition of three levels (2.5, 5.0 and 10.0 %, w/w) of yeast to cereal flour, on average, significantly increased the population of adult and larval progenies relative to the population in yeast-free flour. Considerably higher number of adult beetles developed in wholemeal than in polished flour derived from millet.     

Qualitative variation of anti-diabetic compounds in different tarragon (Artemisia dracunculus L.) cytotypes

Ethanolic extracts of diploid Artemisia dracunculus L. (wild tarragon) from populations in the U.S., and polyploid tarragon from a variety of sources, were screened for the anti-diabetic compounds davidigenin; sakuranetin; 2’,4’-dihydroxy-4-methoxydihydrochalcone; 4,5-di-O-caffeoylquinic acid; 5-O-caffeoylquinic acid and 6-demethoxycapillarisin using LC-MS. Only decaploid plants contained all six target compounds and were the only plants that contained davidigenin and 2,4-dihydroxy-4-methoxydihydrochalcone. These results exhibit the importance of germplasm selection and provenance when studying plants for medicinal activity. Relying only on the “right species” for consistent medicinal activities may not be sufficient, as intraspecific variation may be highly significant.     

Influence of light availability on growth, leaf morphology and plant architecture of beech ( Fagus sylvatica L.), maple ( Acer pseudoplatanus L.) and ash ( Fraxinus excelsior L.) saplings

In a field study, we measured saplings of beech, ash and maple growing in a fairly even-aged mixed-species thicket established by natural regeneration beneath a patchy shelterwood canopy with 3–60% of above canopy radiation reaching the saplings. Under low light conditions, maple and ash showed a slight lead in recent annual length increment compared with beech. With increasing light, ash and maple constantly gained superiority in length increment, whereas beech approached an asymptotic value above 35% light. A suite of architectural and leaf morphological attributes indicated a more pronounced ability of beech to adapt to shade than ash and maple. Beech displayed its leaves along the entire tree height (with a concentration in the middle crown), yielding a higher live crown ratio than ash and maple. It allocated biomass preferentially to radial growth which resulted in low height to diameter ratios, and expressed marked plagiotropic growth in shade indicating a horizontal light-foraging strategy. In addition, beech exhibited the highest specific leaf area, a greater total leaf area per unit tree height, a slightly greater leaf area index, and a greater plasticity to light in total leaf area. Ash and maple presented a “gap species” growth strategy, characterized by a marked and constant response in growth rates to increasing light and an inability to strongly reduce their growth rates in deep shade. In shade, they showed some plasticity in displaying most of their leaf area at the top of the crown to minimize self-shading and to enhance light interception. Through this, particularly, maple developed an “umbrella” like crown. These species-specific responses may be used for controlling the development of mixed-species regeneration in shelterwood systems.     

The infestation of Vicia faba L. (Fabaceae) by Aphis fabae (Scop.) (Homoptera: Aphididae) under the influence of Lamiaceae (Ocimum basilicum L. and Satureja hortensis L.)

Abtract The system Vicia faba–Aphis fabae fabae was studied under the influence of Ocimum basilicum (basil) and Satureja hortensis, in a wind tunnel, in the greenhouse and in field experiments. In the wind tunnel at 20°C both Lamiaceae were deterrent for A. fabae, and S. hortensis proved to be more deterrent than O. basilicum. In experiments in the greenhouse at low temperatures (average minimum 14.6°C, average maximum 24.1°C), A. fabae colonised first and significantly more intense Vicia fabae (field beans) not surrounded by O. basilicum or S. hortensis. At high temperatures (average minimum 18.0°C, average maximum 38.5°C) this relation was inverted: Vicia faba surrounded by the two Lamiaceae were preferred for colonisation (Ocimum basilicum significantly). It showed that pots with Lamiaceae were no obstacle for the aphids to reach Vicia faba. In strip cropping in the field, the repellent effect of Ocimum basilicum proved to be stronger than of Satureja hortensis. In 2002 there was observed only a tendency of lower aphid attack of field beans intercropped with Lamiaceae, while in 2004 and 2005 the infestation of Vicia faba by Aphis fabae was significantly lower in plots intercropped with basil. In plots with Satureja hortensis as intercrop, Vicia faba were significantly lower infested, after 3 weeks. The differences between the results of the wind tunnel/greenhouse at low temperatures, and the field experiments concerning the deterrence by Satureja hortensis cannot be explained. But basing on our results with Ocimum basilicum and those published by other authors, it is recommended to follow up intercropping, after a sincere analysis in every case, in favour of agronomists.     

Chemical composition,insecticidal and biochemical effects of essential oils of different plant species from Northern Egypt on the rice weevil,Sitophilus oryzae L.

The extensive use of synthetic insecticides and fumigants for control stored-product insects has led to the development of resistance. Essential oils from aromatic plants may provide proper alternatives to currently used insect control agents. Essential oils from 20 Egyptian plants were obtained by hydrodistillation. The chemical composition of the oils was identified by gas chromatograph/mass spectrometer. Fumigant and contact toxicities of the essential oils were evaluated against Sitophilus oryzae. The inhibitory effects of the essential oils on acetylcholinesterase and adenosine triphosphatases activities were examined. The oils were composed of monoterpene hydrocarbons (i.e., limonene, sabinene, β-pinene and γ-terpinene) and oxygenated monoterpenes (i.e., terpinen-4-ol, β–thujone, 4-terpineol, α-citral and 1,8-cineole) with the exception of the oil of Schinus terebinthifolius which was contained sesquiterpenes, and the oil of Vitex agnus-castus which contained similar amounts of monoterpenes and sesquiterpenes. In the fumigation assay, the oils of Origanum vulgare (LC₅₀ = 1.64 mg/L air), Citrus lemon (LC₅₀ = 9.89 mg/L air), Callistemon viminals (LC₅₀ = 16.17 mg/L air), Cupressus sempervirens (LC₅₀ = 17.16 mg/L air), and Citrus sinensis (LC₅₀ = 19.65 mg/L air) showed high toxicity to S. oryzae. In the contact assay, the oils of Artemisia judaica, C. viminals, and O. vulgare caused the highest toxicity to S. oryzae with LC₅₀ values of 0.08, 0.09, and 0.11 mg/cm², respectively. The oil of A. judaica (I₅₀ = 16.1 mg/L) invoked the highest inhibitory effect on AChE activity, while the oils of C. viminals and O. vulgare were the most potent inhibitors to ATPases activity with I₅₀ values of 4.69 and 6.07 mg/L, respectively. The results indicate that the essential oils of A. Judaica, O. vulgare, C. limon, C. viminals, and C. sempervirens could be applicable to the management of populations of S. oryzae.     

Free radical scavenging activity of different extracts and some constituents from the leaves of Ligustrum vulgare and L. delavayanum

The free radical scavenging activity of the water infusions, different organic solvent extracts and some constituents from Ligustrum vulgare and Ligustrum delavayanum leaves was assessed with the aid of DPPH radical. Among the samples screened, water infusions had the strongest free radical scavenging capacity. From the tested compounds scavenging active flavonoid aglycones are present in the most active chloroform fractions from both leaves samples.     

Entomotoxic effect of silica nanoparticles against <Emphasis Type="Italic">Sitophilus oryzae</Emphasis> (L.)

Fumigants and residual insecticides are commonly used to combat stored grain pests. In recent years, consumer awareness of the health hazard from residual toxicity and the growing problem of insect resistance to these conventional insecticides have led the researchers to look for alternative strategies for stored grains protection. For example, diatomaceous earth (DE) can be effective against stored grain insects. In this study, DE was used to design amorphous nano sized hydrophilic, hydrophobic, and lipophilic silica in 15–30 nm size range. Nanocides are expected to reduce the volume of application and kinetics of development of resistance in pests. We hypothesized that surface-functionalized silica nanoparticle (SNP) might be a viable alternative to conventional pesticides. Entomotoxicity of SNP was tested against rice weevil Sitophilus oryzae and its efficacy was compared with bulk-sized silica (individual particles larger than 1 μm). Amorphous SNP was found to be highly effective against this insect pest causing more than 90% mortality, indicating the effectiveness of SNP to control insect pests.     

The influence of coppiced teak (Tectona grandis L.F.) regrowth and roots on intercropped maize (Zea mays L.)

Trenching and shoot removal showed the relative influences of living roots and the canopy cast by teak (Tectona grandis L.F.) coppice regrowth on the growth and yield of interplanted maize (Zea mays L.). Teak and maize were planted at 1.8 × 1.8 m and 0.3 × 1.8 m spacing respectively.Competition for light started about four weeks after planting and caused etiolated height growth of maize. When combined with root competition it caused stunted growth. Shading also substantially reduced total dry matter production, grain yield, number of cobs per plant, average cob weight, and weight of grains per cob of maize (P<0.01). Living teak roots alone did not have a significant effect (P>0.05) on maize height growth, total dry matter production, grain yield, number of cobs per plant,average cob weight and weight of grains per cob. However, combined with shading, living roots of teak appreciably reduced total dry matter yield and average cob weight of maize (P<0.01).     

Isoflavone content and estrogenic activity of different batches of red clover (Trifolium pratense L.) extracts: An in vitro study in MCF-7 cells

The estrogenicity of different batches of red clover (Trifolium pratense L., Fabaceae; RCL) extracts and its relationship with the isoflavone content were assessed by measuring MCF-7 cell proliferation by flow cytometry and propidium iodide staining. RCL extracts were compared to estradiol (E2) and to the main RCL isoflavones biochanin A, daidzein, genistein and formononetin. Isoflavone content in the extracts was assayed by HPLC.E2 and isoflavones increased MCF-7 proliferation in a concentration-dependent fashion, with the following potency order: E2 >>> genistein > biochanin A = daidzein > formononetin. Extracts increased MCF-7 proliferation with different potencies, which in four out of five extracts correlated with the ratios 5,7-dihydroxyisoflavones/7-hydroxyisoflavones. The efficacy of all extracts increased with decreasing genistein contents. A solution containing the main isoflavones at the average concentration of RCL extracts increased MCF-7 proliferation with higher potency and steeper concentration–response curve. The effects of E2, of RCL extracts and of the isoflavone solution were inhibited by the estrogen receptor antagonist 4-hydroxytamoxifen.Flow cytometric analysis of MCF-7 proliferation is a suitable bioassay for the estrogenicity of RCL extracts, thus expanding the characterization of individual batches beyond assessment of chemical composition and contributing to improved standardization of quality and activity.