Effects of seed potato tuber treatment with imidacloprid on some soil and foliar insects in Croatia

The treatment of seed potato tubers by imidacloprid, as well as the standard granular insecticides applied in the furrow, did not, in four years of trials, sufficiently prevent damage from wireworms, noctuid larvae and mole crickets to potato tubers. The main reason for this failure is the spatial and temporal distance between the application of insecticides and the moment when their action is needed. On the other hand, the effects of imidacloprid applied as seed tuber treatment on the larvae of the Colorado potato beetle was very good: depending upon conditions, it lasted from at least 55, to 70 days at the most. It protected the foliage from any substantial damage from the entire first generation, and ensured high yields. Therefore a decision on seed tuber treatment with imidacloprid in Croatia should primarily depend upon the cost/benefit calculation based on damage expected from the CPB (or aphids), and not from soil insect pests.     

Erfahrungen über den Einsatz des Phosphorwasserstoffpräparates PHOSTOXIN in Jugoslawien

Summary This report is dealing with the fumigation of grain in granaries with phosphine against the main stored-grain insects in Yugoslavia. The phosphine gas was generated from PHOSTOXIN tablets which were inserted in the grain mass. The efficacy was tested by the mortality of laboratory-bred insects and insects of the natural infestation. The successful fumigation was depending on the temperature of the grain and of the storage rooms and on the exposure period. The covering of the grain mass by plastic sheets reduced the gas leakage considerably. The dosage of 5–6 tablets per ton of grain and an exposure time of 5 days resulted in a 100% mortality of all insect stages at a grain temperature of 19° C. In all trials the exposure time proved to be the main factor. For the control of the angoumois grain moth and the Indian meal moth in the storage rooms outside the grain mass an additional treatment with an insecticidal spray was necessary. The control of hot spots by inserting the tablets through a probe was successful, provided that these hot spots were not too numerous and could be marked off very accurately.

---

---

Die Übersetzung aus dem Jugoslawischen besorgte Herr Dipl.-Ing. MAYR, die Bearbeitung des deutschen Textes erfolgte durch Herrn. Dr. F. NEUBECKER; beide Deutsche Gesellschaft für Schädlingsbekämpfung m. b. H., Frankfurt a. M.     

Combinations of several insecticides used for integrated control of Colorado potato beetle (Leptinotarsa decemlineata, Say., Coleoptera: Chrysomelidae)

The Colorado potato beetle (Leptinotarsa decemlineata Say.) (CPB) is the main potato pest in Croatia. The main problems in CPB control are related to a number of treatments and resistance development. In order to investigate the efficacy of combinations a reduced dose of spinosad (33% of the full doses) with the reduced doses (33% of full doses) of B.t.t., neem and pyrethrin against CPB larvae, 3-year field trials and one laboratory trial were conducted. Joint actions of the insecticides in combinations were analyzed. The CPB attack on experimental fields in all 3 years of investigation was high to moderate. In 2001 the maximum number of larvae on untreated plots was 11.7 larvae per plant, while in 2002 and 2003 it was lower, 5.5 and 6.1 larvae/plant, respectively. The efficacy obtained with a full dose of B.t.t. reached 75% in the field, and 78% in the laboratory trial. The residual efficacy of a full dose of B.t.t. lasted 7–10 days. The application of both, full and reduced doses of B.t.t., did not result in a significant yield increase. The results indicate that only one treatment with B.t.t. insecticide alone is not enough for efficient protection of potato against the attack of CPB larvae. The application of neem resulted in an efficacy of between 54 and 87.9%. The residual activity of neem was too short to ensure significant yield increase in 2 out of 3 years of the investigation. The application of a full dose of pyrethrin ensured an efficacy of between 86 and 89% with residual activity of 7–10 days. Only in the trial in 2003 significant yield increase (40% higher than untreated control) after the application of a full dose of pyrethin was recorded. The application of both, full and reduced doses of spinosad resulted in very high efficacy (over 90%), with residual activity between 10 and 20 days. The application of spinosad resulted in a significant yield increase in 2003, both in full and reduced doses, and in 2001 in the full dose (the reduced dose was not tested alone in 2001). High efficacy of the reduced dose of spinosad indicated its high biological activity and possibility for the reduction of the recommended dose. However, applications of combinations of insecticides in reduced doses (spinosad with B.t.t., neem and pyrethrin) resulted in efficacies of over 97% with residual activity of up to 21 days. Significant yield increase was noted after the application of the combinations of spinosad with B.t.t. and pyrethrin. The results of the laboratory trial confirmed the results of field trials. The joint action of insecticides was mainly described as independent synergism. It can be concluded that applied combinations are suitable in IPM in potato.     

Preliminary assay on the antioxidative activity of Laurus nobilis extracts

Antioxidative activity of Laurus nobilis leaves, bark and fruit methanolic extracts (crude and defatted) were studied on the level of lipid peroxidation in liposomes, induced by Fe(2+)/ascorbate system and measured spectrophotometrically by the TBA-test. The most significant inhibition of lipid peroxidation was obtained with methanolic extracts of laurel bark (70.6% of inhibition was obtained with 1.0 mg of crude extract).     

Vergleichende Untersuchung von Phosphorwasserstoff entwickelnden Präpapaten zur Getreidebegasung

Zusammenfassung Die Ergebnisse der hier dargestellten Versuche zeigen, sowohl bezüglich der Verteilung des Phosphorwasserstoffes im Getreide als auch bezüglich der Wirksamkeit der PH₃-Präparate auf die Abtötung der Schädlinge, eindeutig, daß die Art der Verteilung der Präparate eine wesentliche Rolle für den Begasungserfolg spielt. Hierbei stellt das Gewicht der Präparate (Pellet, Tablette, Beutel) einen entscheidenden Faktor für ihre Verteilung im Getreide und damit für den Erfolg der Begasung dar.Selbstverständlich ist auch das Präparat in Beutelform brauchbar für die Begasung von Schä dlingen in gelagertem Getreide. Der Hauptunterschied zwischen dem Beutel und der Tablette bzw. dem Pellet in der praktischen Anwendung besteht aber darin, daß Tablette und Pellet durch ihre gleichmäßigere Verteilung eine bessere Wirksamkeit m der Abtötung der Schädlinge bei gleichzeitig geringerer Dosierung pro Tonne Getreide besitzt.Bei der Getreidebegasung spielen schließlich auch ökonomische Gesichtspunkte eine Rolle.Es kann also der Schluß gezogen werden, daß Präparate in Papierbeuteln für die Getreidebegasung weder anwendungstechnische noch ökonomische Vorteile gegenüber dem bei uns bisher bekannten Tabletten- bzw. Pellet-Präparat besitzt.Auf Grund der Ergebnisse dieser Versuche wie auch der bisher gemachten Erfahrung bei der Anwendung von PH₃-Präparaten in der Getreidebegasung kann gesagt werden, daß Präparate wie Tabletten und Pellets für unsere Bedingungen sowohl hinsichtlich der Wirksamkeit gegenüber Getreideschädlingen wie auch in ökonomischer Hinsicht ausgezeichnet verwendbar sind.

---

Summary Referring to the distribution of hydrogen phosphide in grain as well as to the effectiveness of the PH₃ preparations for the destruction of insect pests, the results of the herein described tests show clearly that the method of distribution of the preparations plays an essential part for the success of the fumigation. Hereby the weight of the preparations (pellet, tablet, bag) is a decisive factor for their distribution in grain and therefore also for the succes of the fumigation.Naturally, the preparation in bags is also usable for the fumigation of insect pests in stored grain. The main difference between bag and tablet, respectively pellet, in the practical application lies, however, in the fact that tablet and pellet, due to their more uniform distribution, are more effective for the destruction of insect pests allowing at the same time a reduced dosage rate per ton of grain. Last but not least, economical aspects represent an important factor in grain fumigation.It, therefore, can be concluded that reparations in paper bags have no advantages in grain fumigation, as far as technique of application and economy are concerned, when compared with the tablet and pellet preparations so far known in this country.Based on the results of these tests and on the experience gained in application of PH₃ preparations in grain fumigation, one can say that preparations like tablets and pellets are most suitable under our conditions as far as efficacy against grain insect pests and economical aspects are concerned.

---

---

Karadjordjeva 17 (Jugoslawien)     

Outbreak of tuberculosis caused by Mycobacterium caprae in a zoological garden

In the autumn of 2004, tuberculosis caused by Mycobacterium caprae occurred in a zoo in Slovenia. A dromedary camel (Camelus dromedarius) was killed after a history of progressive emaciation. Necropsy findings indicated disseminated tuberculosis, which was confirmed by cultivation of M. caprae. Consequently, a tuberculin skin test was performed in all epidemiologically linked animals and another dromedary camel and six bison (Bison bison) were positive and killed. Mycobacterium caprae was isolated from two bison while M. scrofulaceum and Mycobacterium spp. were found in two other bison, respectively. The second dromedary camel was found to be negative for mycobacteria under both microscopic and culture tests. The isolates were investigated with commercial identification kits, IS6110 PCR, IS6110 restriction fragment length polymorphism analysis, spoligotyping and mycobacterial interspersed repetitive units typing. Genotyping results revealed that the dromedary camel and the two bison were infected by the same M. caprae.     

Immunomodulatory effects of the methanolic extract of Epimedium alpinum in vitro

The effect of the methanolic extract of root and rhizome of Epimedium alpinum (MEEA) on phenotype and functions of rat lymphocytes in vitro was studied. It has been found that MEEA at lower concentrations (0.1 microg/ml and 1 microg/ml) significantly enhanced proliferation of splenocytes and thymocytes triggered by concanavalin A (Con A), whereas higher concentrations of the extract (50 microg/ml-500 microg/ml) were inhibitory. The stimulatory effect of MEEA on Con A-induced proliferation of splenocytes correlated with the up-regulation of interleukin-2 receptor alpha (IL-2Ralpha) expression. In addition, increased production of IL-2 was observed when a blocking IL-2Ralpha monoclonal antibody (mAb) was added to cell cultures. MEEA-suppressed proliferation of splenocytes was due to the inhibition of IL-2 production, the down-regulation of IL-2Ralpha expression and the induction of apoptosis. Cellular proliferation in the presence of inhibitory concentrations of MEEA higher than 50 microg/ml could not be restored by the addition of exogenous IL-2.     

Levamisole synergizes experimental F4ac+ Escherichia coli oral vaccine in stimulating ileal Peyer's patch T cells in weaned pigs

Recent findings demonstrate that priming by levamisole of weaned pigs experimentally vaccinated against postweaning colibacillosis (PWC) contributes to immune protection from challenge-induced clinical disease through stimulation of the mesenteric lymph node cells that participate in cell-mediated immunity. With the objective of better understanding the mechanisms by which levamisole induces protective mucosal cell-mediated immune response to vaccination against PWC, it was tested whether the drug synergizes experimental F4ac+ Escherichia coli oral vaccine in stimulating T cells also in the jejunal lamina propria (JLP) and ileal Peyer's patch (IPP) upon virulent challenge. Commercial crossbred pigs weaned at 4 weeks were allocated into two equal groups. The experimental group was i.m. primed with levamisole at an immunostimulatory dose of 2.5 mg/kg once daily, for 3 consecutive days, and controls received saline. Both groups were vaccinated orally with the vaccinal E. coli strain on day 0 and challenged with the virulent E. coli strain 7 days later. All pigs were killed on postchallenge day 6. The results determined by immunophenotyping of isolated cells indicate that priming by levamisole of the vaccinated weaned pigs selectively recruited and activated T cells in the IPP, a lymphoid organ-generating B lymphocytes. The pig IPP is normally populated with up to 5% of CD3+ T cells and CD6 is an activation antigen expressed exclusively by T cells in swine. Therefore, a significantly higher number of CD3+ (P < 0.01) and CD6+ (P < 0.001) cells observed within the IPP follicles of the primed-vaccinated vs. unprimed-vaccinated challenge-infected pigs suggest enhanced T cell-mediated immunity in this B-cell compartment induced by the potentiating action of the drug and vaccine. The ability of levamisole to influence interaction between activated T cells and B cells in the IPP of primed-vaccinated weaned pigs, and the possibility that this interaction plays a role in regulating B-cell maturation within the IPP follicles, are discussed.