Alternative fumigants to methyl bromide for the control of pest infestation in grain and dry food products

The primary aim of the current study is to evaluate the potential use of the known isothyiocyanates (ITC) as compared to a new ITC isolated from Eruca sativa (salad rocket) as fumigants for the control of stored products insects. The biological activity of methyl iodide (CH3I), carbon disulphide (CS2), benzaldehyde (C7H60) and essential oils were also evaluated. The toxicity of the various fumigants was assessed against adults and larvae of a number of major stored-product insects. ITCs are potential candidates because only very low concentrations are needed for the control of stored-product insects. It should be mentioned that Eruca sativa is used worldwide as a food supplement. Methyl thio-butyl ITC the main bioactive component in this plant has high toxicity against insects, but lower mammalian toxicity as compared to other active ITCs. Comparative studies with CH3I, CS2 and C7H60 showed that the first was the mot active compound against stored-product insects followed by the second and the third. CH3I was found less sorptive and to be less penetrative in wheat than CS2. The activity of some essential oils was also evaluated. In this context, we should keep in mind that a general consensus is very difficult to achieve in order to introduce broadspectrum fumigants like methyl bromide or phosphine. Because of this, alternative fumigants could be developed against particular species of insects or to be used for specific food product commodity. Keywords: Fumigants; Isothiocyanates; Methyl iodide; Carbon disulfide; Benzaldehyde

Improvement of phosphine fumigation by the use of Speedbox

Today, phosphine is turning to be a major fumigant for controlling insects in stored products. However, few limitations, such as low temperatures and relatively long exposure time, limit the phosphine use. In order to improve phosphine application, a special devise, containing a heater and a ventilator, called "Speedbox" has been developed by Detia Degesch GmbH Germany. For studying the effectiveness of phosphine fumigation using Speedbox, we have conducted two kinds of experiments: one in a fumigation room (Pilot) and other in commercial warehouse. For pilot fumigation, adults, pupae and late larvae of Sitophilus oryzae, Rhyzopertha dominica, Oryzaephilus surinamensis, Trogoderma granarium and Callosobruchus maculatus, and all stages of Tribolium castaneum Herbst, Plodia interpunctella and Ephestia cautella were used as test insects. One to three Degesch Plates (about 2-6 g of phosphine gas per m3) were used. Exposure time was 1 to 3 days. The phosphine concentrtion was monitored by Bedfont device model 415. At 4 g/m3 for 48 ha maximum of phosphine concentration of 1460 ppm was reached. The total mortality of all tested insects and stages was recorded, except the eggs of E. cautella (98%). The commercial stack fumigation was done at the dosages of 2-4 g/m3, exposure time of 2-4 days and commodity temperatures of 6-17ºC. At a target concentration of 4 g/m3, 2 hours after beginning of the treatment, the concentration of the gas has reached 414 ppm, with a maximum of 1480 ppm. The total mortality of tested insects at adult, late larvae and pupae stages was recorded. The use of Speedbox allows one-day decrease in the plates degassing time, recirculation of the gas and its event distribution in the treated space and controlling major stored product insects for shorter exposure time at low temperatures. Keywords: Fumigation; Posphine; Speedbox; Stored-product insect

Laboratory evaluation of diatomaceous earth against main stored product insects

The sensitivity of the main external and internal stored product insect pests to the commercial formulation of Detia Degesch Diatomaceous Earth – DDDE - Inerto (DE) was studied in laboratory experiments. The tested insects were adults of internal feeders Sitophilus oryzae Rhyzopertha dominica and external feeders Oryzaephilus surinamensis, Tribolium castaneum, and larvae (third instar) of T.castaneum. The DE was applied to wheat grain of 12% moisture content at concentrations of 0.5, 1.0, 2.0 and 4.0 g/kg of grain. The treated and untreated (control) grain were kept at 28°C and 65 ± 5% r.h. The numbers of dead and survived insects were counted two, three and four weeks after treatment. The number of adult progeny was counted nine weeks after treatment. At a concentration of 0.5 g/kg, mortality of S. oryzae and O. surinamensis after three weeks of exposure to DE were 92 and 86%, respectively. In contrast, mortality of T. castaneum and R. dominica adults was 3 and 37%, respectively. Progeny production of O. surinamensis and T. castaneum at a concentration of 2 g/kg was negligible, since only few individuals were recorded nine weeks after treatment, in comparison with the high progeny production in the control grain. The progeny of S. oryzae was also reduced. In contrast, for R. dominica was reduced only twice, in comparison with the control. In the case of T. castaneum larvae, at a concentration of 2 g/kg, after 4 weeks of exposure, 37% of the larvae emerged to adults, compared with 95% in control. Nine weeks after treatment, the number of F1adults was 100% suppressed. DE efficacy was similar at 4 g/kg. Based on the findings of the present study, the efficacy of the tested DE was influenced by DE concentration, insect species, developmental stage and exposure interval to the treated commodity.Keywords: Diatomaceous earth, Stored product insects, Wheat grai

Liquidation of Corporation

Import 22/07/2015Diplomová práce se zabývá procesem likvidace obchodních společností v České republice. Cílem této práce je popsat postup likvidace obchodních společností a upozornit na některé problémy, které proces likvidace s sebou přináší, poukázat na řešení základních organizačních a ekonomických otázek související s likvidací a propojit právní a daňový pohled na likvidaci. Práce je rozdělena do čtyř kapitol. V první kapitole jsou definovány jednotlivé právní formy obchodních společností a možné způsoby jejich zrušení. Druhá kapitola se zabývá popisem likvidačního procesu, kdy jsou popsány jednotlivé kroky likvidátora v průběhu likvidace. Třetí kapitola je věnována osobě likvidátora, podmínky nutné k výkonu likvidátora, povolání likvidátora do funkce. Čtvrtá kapitola je věnována praktickým problémům spojenými s procesem likvidace.Thesis deals with the process of liquidation of corporations in the Czech Republic. The aim of this thesis is to describe the procedure of liquidation and to point out some possible problems that could occur during liquidation. The legal and tax point view of the topic will also be included. Thesis is divided into 4 main chapters. Different legal forms of the corporations and the ways of dissolution of companies are defined in the first chapter. The second chapter pursues the process of liquidation. One part of this chapter is devoted to activities of the liquidator. The person of the liquidator, including his competences and required skills, is described in the third chapter. The last chapter is focused on practical problems concerning the process of liquidation.119 - Katedra právavelmi dobř

QUALITY, EFFICACY AND SAFETY OF PHYTOMEDICINES AND PHYTOCOSMETICS

Laboratory studies were conducted to evaluate the fumigant and repellent properties of essential oils extracted from the leaves of Ocimum americanum L. against five storage insects, Sitophilus oryzae L., Rhyzopertha dominica F., Tribolium castaneum (Herbst) and Callosobruchus chinensis F. Each essential oil was tested at four (0, 1, 5 and 10 µl/L air) and five (0, 0.5, 1.0, 1.5 and 2.0 µl oil/ g grain) rates in space fumigation and choice bioassay studies, respectively, with four replicates per treatment. In space fumigation studies, leaf essential oil at 10 µl/L air 24 h after treatment, caused 88.8, 87.5, 11.3 and 100% kill of S. oryzae, R. dominica, T. castaneum and C. chinensis insects, respectively, whose corresponding LC50 values were 0.38, 0.49, NS and 0.18 µl/L air, respectively. The LC50 values varied with plant part from which the essential oil was extracted. Leaf essential oil was most efficacious (0.18-0.49 µl/L air) followed by fruit (1.15-15.07 µl/L air) and stem (3.70-34.68 µl/L air) essential oils, respectively. In the choice bioassay studies, fruit essential oil (at 2.0 µl oil/ g grain and 24 h) produced highest repellence against S. oryzae and R. dominica with PR values of 81 and 94%, respectively. Under the same conditions, the leaf essential oil had PR values of 51 and 83% against adult T. castaneum and C. chinensis insects, respectively. Results of this study demonstrate the potential use of plant volatiles as alternatives to the synthetic fumigants and their applicability for preservation of stored food commodities in subsistence agriculture. Key words: Callosobruchus chinensis, Oryzaephilus surinamensis, Rhyzopertha dominica, Sitophilus oryzae, Tribolium castaneum, Ocimum americanum, Essential oil, Fumigant toxicity, Repellence, *Corresponding author: Email: [email protected] (J.O. Ogendo) Fax: +254-51-62145/62442 Cell phone: +254-722-892504; +254-738-41221

BIOACTIVITY OF OCIMUM AMERICANUM L. ESSENTIAL OILS AGAINST FOUR INSECT PESTS OF STORED FOOD COMMODITIES

Laboratory studies were conducted to evaluate the fumigant and repellent properties of Ocimum americanum L. essential oils against adult Sitophilus oryzae L., Rhyzopertha dominica F., Tribolium castaneum (Herbst) and Callosobruchus chinensis F. Each essential oil was tested at four (0, 1, 5, 10 µl/L air) and five (0, 0.5, 1.0, 1.5, 2.0 µl oil/ g grain) rates in space fumigation and choice bioassay studies, respectively, with four replicates per treatment. Corrected percent mortality and PR were arcsine transformed before ANOVA and means separated by Tukey’s HSD test [1, 2]. Dose-responses were further subjected to Probit analysis and LC50 values computed [3]. Leaf essential oil at 10 µl/L air 24 h after treatment, caused 88.8, 87.5, 11.3 and 100% adult mortality of S. oryzae, R. dominica, T. castaneum and C. chinensis, respectively (LC50 values of 0.38, 0.49, NS and 0.18 µl/L air, respectively). The LC50 values varied with plant part assayed. Leaf essential oil was most efficacious (LC50 values: 0.18-0.49 µl/L air) followed by fruit (1.15-15.07 µl/L air) and stem (3.70-34.68 µl/L air) essential oils, respectively. In the choice bioassay studies, fruit essential oil (at 2.0 µl oil/ g grain and 24 h) produced highest PR values of 81 and 94% against S. oryzae and R. dominica, respectively. Similarly, the leaf oil repelled 51 and 83% of T. castaneum and C. chinensis, respectively. Clear intra-species variations in essential oil compositions and inter-insect species differences form the basis of differential bioactivity observed. Leaf oil was high in monoterpenes whereas stem and fruit oil were high in sesquiterpenes. Results show that plant volatiles are potential alternative grain fumigants and further validation studies required for compatibility with tropical agriculture. Refrerences: [1] Rajendran, S. and Muralidharan, N. Effectiveness of allyl acetate as a fumigant against five stored grain beetle pests. Pest Management Science 61: 97-101 (2005). [2] Rozman et al. Toxicity of naturally occuring compounds of Lamiaceae and Lauraceae to three stored-product insects. Journal of Stored Products Research 43(4): 347-355 (2007). [3] Finney, D.J. Probit Analysis, 3rd ed. Cambridge Univ. Press, London (1971)

Ligand-binding properties of a juvenile hormone receptor, Methoprene-tolerant

Juvenile hormone (JH) is a sesquiterpenoid of vital importance for insect development, yet the molecular basis of JH signaling remains obscure, mainly because a bona fide JH receptor has not been identified. Mounting evidence points to the basic helix–loop–helix (bHLH)/Per-Arnt-Sim (PAS) domain protein Methoprene-tolerant (Met) as the best JH receptor candidate. However, details of how Met transduces the hormonal signal are missing. Here, we demonstrate that Met specifically binds JH III and its biologically active mimics, methoprene and pyriproxyfen, through its C-terminal PAS domain. Substitution of individual amino acids, predicted to form a ligand-binding pocket, with residues possessing bulkier side chains reduces JH III binding likely because of steric hindrance. Although a mutation that abolishes JH III binding does not affect a Met–Met complex that forms in the absence of methoprene, it prevents both the ligand-dependent dissociation of the Met–Met dimer and the ligand-dependent interaction of Met with its partner bHLH-PAS protein Taiman. These results show that Met can sense the JH signal through direct, specific binding, thus establishing a unique class of intracellular hormone receptors