Ein praxisnaher Versuch zur Ermittlung der Dauerwirkung von Bacillus thuringiensis Berliner gegen die Dörrobstmotte Plodia interpunctella Hbn in einem Getreideschüttbodenlager

In order to test, under warehouse conditions, the longterm effectiveness of THURICIDE® dust, containingBacillus thrungiensis var.kurstaki (=Serotype H_{3a, 3b}), with a viable spore count of 6 to 10 million per mg, the biopreparation was applied to rye, stored in bulk, on which larvae of the Indian Meal Moth (Plodia interpunctella Hbn.) were fed. From May to October, moth eggs were exposed monthly to rye dusted with 100 mg (320×10³ IU) resp. 150 mg (480×10³ IU) THURICIDE® dust per 100 g grain respectively. At a concentration of 100 mg 0.2% to 2.4% of the larvae, which hatched from the eggs in May, June and August, survived to the adult stage. No moths were observed in the experiments continued during September and October. At a cocentration of 150 mg, only in the experiments started in June and July 2.7% and 0.1% respectively of the eggs and larve survive to become adults. In the experiments of May, August, September and October, none were stated to have survived. The biopreparation-free control of May, June and July showed that about 75% of the eggs/larvae reached the adult stage, whereas, in August, September and October, untreated eggs and larvac reaching the adult stage amounted to 14% and 1% respectively. In reason of the combination of the efficiency ofBacillus thuringiensis and of the only small amount of surviving larvae due to the low temperatures during autumn and winter months, the surface application of THURICIDE® dust would be promising measure for combatting moth pests in bulk-stored grain.     

Rasterelektronenmikroskopische Untersuchungen an von Vorratsschädlingen angegriffenen Verpackungsfolien aus synthetischen Kunststoffen und abgewandelten Naturstoffen

Packaging foils made of cellulose actetate, cellophane, polyethylene, polypropylene, polystyrene, polyester, polyvinyl chloride, attacked byRhizopertha dominica F.,Stegobium paniceum L.,Tribolium castaneum Hbst. and larvae ofPlodia interpunctella Hbn. were examined with the scanning electron microscope (SEM). Because of the destruction marks made by the insects, it is possible to determine with the SEM the side of packaging material which has been attacked by the pests. Due to the shape and position of the mouthparts of the insects the gnawing marks are rather typical for the different species. By means of a standard of comparison it might be possible to determine the family and perhaps the genus or species of the insects involved. The influence of shape and size of the mouthparts as well as the position of the mandibles in relation to the anatomy and to the axis of the body on the gnawing ability of stored-product pests is discussed. The reasons for the insect resistance of packaging materials are discussed (smoothness of the surface, rigidity, thickness).     

Einsparung von Herbiziden bei gleichzeitiger Erhöhung des Zuckergehaltes bei Zuckerrüben

The present trial was destined to find out whether it is possible to reduce the herbicides-amount of application by 50% i.e. on the one hand with normel water and on the other hand on a basis of Carborain-CO₂-water. The effects resulting from this in comparison with the full-application amount control, should be estimated. After the one year trial in summary one can say that in general the level of yield between half and full application amount did not vary substantially. Though the yield of each of the plots sprayed with CO₂-water were higher than the comparable normal water plots. Far extremer was the comparison of the sugar content. The sugar content of the reduced normal water plot was even below the one of the control. In comparison to that with the Carborain-water a higher sugar content by 5% relative was ashieved.     

Wirksamkeit des Kieselgurpräparates Dryacide® gegen vorratsschädliche Insekten

The diatomaceous earth (DE) Dryacide^® was tested under laboratory conditions on surfaces (2 g DE/m²) and in wheat grain (3 kg DE/t wheat) at a relative humidity of 70±5% and a temperature of 22±1°C. The wheat had a moisture content of 14.5%. The effect of surface treatments was tested onEphestia kuehniella, Oryzaephilus surinamensis, Tenebrio molitor andTribolium castaneum. The efficacy of grain treatments was determined usingEphestia elutella, O. surinamensis, Sitophilus granarius andTribolium confusum. In both treatments adult and larval stages were included.100% mortality were reached with the surface treatments in adults and larvae ofO. surinamensis and the adults ofT. molitor andE. kuehniella after an exposition time of 3–9 days. AgainstT. castaneum and the larvae ofT. molitor andE. kuehniella no complete control could be achieved.In the grain treatments the dosage of 3 kg DE/t wheat reached 100% mortality in all tested pests exceptS. granarius. Most sensitive wereO. surinamensis andE. elutella. InT. confusum the adults died within 13 days of treatment, but for complete control of the larvae 13 weeks were necessary. AgainstS. granarius the silica dust showed no satisfactory efficacy, because 49 days after beginning of the examinations beetles of the progeny hatched. Dryacide^® could not prevent the reproduction of the granary weevil, but there was a lower number of progeny compared to the untreated control.     

Mortalität des Kornkäfers,Sitophilus granarius,bei Begasung mit Methylbromid in Abhängigkeit von der relativen Luftfeuchte

the mortality of the grain weevil,Sitophilus granarius, treated with methyl bromide at 25° and 30°C is influenced by the relative humidity. The concentrationtime product for a mortality of 90% increases significantly with humidity.     

Zum Geschlechtsverhältnis von Ips typographus (L.) (Coleoptera,Scolytidae) in Pheromonfallen

By means of barriere traps baited with two types ofIps typographus pheromone, Typolur and Pheroprax, nearly 240000 individuals were trapped between 1979 and 1981 in bohemian spruce stands. In the whole 64% (Typolur) resp. 61% (Pheroprax) of the beetles were females. At the beginning of the flying period the males predominated whereas some weeks later on the contrary the females were prevalent. The latter consisted of individuals founding sisterbroods. Up to 5.2% of females had lost their bristles showing that they already were through three egg laying periods.     

Untersuchungen über die Wirkung von Bacillus thuringiensis Berliner auf die Dörrobstmotte (Plodia interpunctella Hbn.)

For testing the prompt and long-term effectiveness of a THURICIDE-dust containingBacillus thuringiensis var.kurstaki, serotype 3a, 3b with a viable spore count of 6 to 10 million per mg and an insecticidal activity of 3,2×10³ international units (IU) per mg, the biopreparation was applied to rye on which larvae of the Indian Meal Moth (Plodia interpunctella Hbn.) were fed. A concentration of 20 mg (64×10³ IU) of dust in 100 g of grain caused in 82% mortality, and a six-fold higher concentration (120 mg, 384 × 10³ IU respectively) resulted in 99,0% mortality. The efficiency of the preparation was not reduced by storage for as long as 5 months in any five tests, which were at temperatures from 12°C to 28°C with 75% r.h. The larval stage of the surviving was prolonged by 3 to 4 weeks. Surviving moths, whose larvae were reared on grain to which the preparation was applied, were fertile and did not infest the following generation.