Eine rationalisierte Methode zur Zucht des BuchdruckersIps typographus L. (Coleoptera,Scolytidae)

A newly developed method for rearing ofIps typographus L. is presented. This method minimizes the input of labour and improves the success of rearing.     

Über die Empfindlichkeit von Syrphidenlarven gegen Pflanzenschutzmittel

Zusammenfassung In einigen nach verschiedenen Methoden durchgeführten Testversuchen wird festgestellt, daß Syrphidenlarven durch eine Reihe von aphidiziden Pflanzenschußmitteln völlig oder zum Teil ausgeschaltet werden; dies gilt insbesondere für direkten Kontakt mit diesen Mitteln. Junglarven sind giftempfindlicher als Altlarven. Durch Applikation systemisch wirkender Mittel an syrphidenfreie Teile der Pflanzen kann die Mortalität dieser Blattlausfeinde beträchtlich gesenkt werden.     

Yield, yield components and plant architecture in the F3 generation of common bean (Phaseolus vulgaris L.) derived from a cross between the determinate cultivar ‘Prelude’ and an indeterminate landrace

Growth trials were conducted outdoors in the UK to determine the yield, yield components and plant architectural differences between determinate and indeterminate Phaseolus vulgaris bean plants. F3 lines derived from crosses between ‘Prelude’, a determinate cultivar and ‘V8’, an indeterminate landrace, were grown together with the parents and ‘Carioca’, an indeterminate landrace from Brazil. Data were recorded on flowering date, number of nodes on main stem at flowering, plant height at maturity, number of pods/plant, number of seeds/pod, number of seeds/plant, 100-seed weight, seed mass/plant, percentages of diseased and healthy seeds/plant. Determinate F3 lines had significantly lower (P < 0.05) seed mass/plant, fewer pods/plant, fewer seeds/pod, fewer seeds/plant, lower harvest index, shorter stems, earlier date of flowering, fewer nodes at flowering and fewer healthy seeds/plant than indeterminate F3 lines. However, determinate genotypes had significantly larger (P < 0.05) pods to accommodate their larger seeds compared with indeterminate lines. A similar situation was found when the yield and yield components of ‘V8’, ‘Prelude’ and ‘Carioca’ were evaluated; the highest seed mass/plant was given by ‘V8’ and the lowest by ‘Prelude’. Furthermore, some indeterminate genotypes with Type IV growth habit yielded significantly higher (P < 0.05) than the high-yielding parent, ‘V8’, indicating a positive influence on seed yield by crossing different genotypes.     

Quantifying the fine scale (1km × 1km) exposure,dose and effects of ozone: Part 2 estimating yield losses for agricultural crops

In Britain wheat is an important crop accounting for 41% of the total cereal production. In this study ozone concentrations for 1989 estimated as described in Part 1 of the paper are integrated with the estimated wheat distribution to derive a detailed estimate of the impact of ozone on wheat yields at a fine spatial scale (1km × 1km). These data provide estimates for calculating regional and national yield losses. The methodology can be applied to other crop species. Recent research on a range of crops has established relationships between the economic yield loss for certain crops, including wheat, and ozone exposure. Exposure is described as the accumulated exposure above a threshold experienced during the daylight hours (AOT). Critical AOT values are derived from yield exposure relationships which show linear reductions of yield loss with increasing ozone concentrations. This study has made use of land cover data from remotely sensed imagery at 25m resolution and nationally collected agricultural statistics for counties. These data were combined using an areal interpolation technique to provide more spatially articulate estimates of the location and intensity of wheat production. The results demonstrate the economic importance of ozone as a pollutant. Wheat yield losses attributed to ozone vary between different parts of the country but, for years when ozone levels are high, yield losses are likely to be significant in some areas.     

Simultaneous analysis of grain and grain-based products for ethylene dibromide, carbon tetrachloride, and ethylene dichloride

A method is described for the simultaneous measurement of parts per billion levels of the fumigants ethylene dibromide, carbon tetrachloride, and ethylene dichloride in grain and grain-based products. The fumigants are isolated by hexane co-distillation, separated by capillary gas chromatography, and detected with a mass spectrometer in the selected ion monitoring mode. Recoveries are greater than 90% and standard deviations are approximately 10% of the quantity measured. The method is free of interferences and its precision and accuracy are enhanced by the use of tetradeuterated ethylene dibromide and ethylene dichloride as internal standards.     

Increasing incomes of Malian cotton farmers: Is elimination of US subsidies the only solution?

In a WTO battle and the press the argument is often made that eliminating US cotton subsidies would have a large effect on the incomes and competitive position of farmers in developing countries. In Francophone West Africa cotton productivity has stagnated after rapid gains in the first two decades following independence (1960-1980). A farm model was constructed based on farmers’ definition of their decision-making framework which they use to respond to income and weather risks. With this model the effects on farmers of eliminating US subsidies are compared with various productivity increasing measures for cotton and sorghum in Dioila, Mali. Dioila is located in a representative cotton region producing 16% of the cotton in Mali. We include sorghum due to its importance for consumption and the observation of Malian farmers substituting cereals (sorghum and maize) for cotton as the returns to cotton have fallen in the 21st Century. In the farm model, the elasticity of transmission of a change in the world cotton price to the farm gate price is taken into account. The gains from eliminating US subsides are small. In contrast, the various technological alternatives including Bt cotton introduction, the use of higher fertilization levels for cotton, and the introduction of improved sorghum cultivars and moderate fertilization along with a marketing package all have substantially higher returns Even with substantial improvement in the mechanisms enabling farmers to benefit from the higher prices resulting from elimination of US subsidies, there are still much higher returns resulting from the various types of productivity increases.     

Use of transesophageal atrial pacing to provide temporary chronotropic support in a dog undergoing permanent pacemaker implantation

A 14.5-kg, 13-year-old female spayed Cocker spaniel was evaluated because of episodic hind limb weakness. Results of examination were consistent with sick sinus syndrome with intermittent second-degree atrioventricular block. Transesophageal atrial pacing was successful in providing chronotropic support during permanent pacemaker implantation. Transesophageal atrial pacing appears to be a viable option for temporary atrial pacing in dogs with hemodynamically marked bradycardia without significant atrioventricular blockade.     

Confirmation of hybrid origin in Arisaema (Araceae) using molecular markers

A population of hybrids between Arisaema triphyllum subsp. stewardsonii and A. dracontium was investigated using molecular markers to document the hybrid origin. Total genomic DNA was extracted from A. triphyllum, A. dracontium, and the hybrids, and subjected to sequence analysis of various regions of intergenic spacer and genes of chloroplast or intergenic spacer and genes of nuclear ribosome for single nucleotide polymorphisms (SNPs). Clustering was performed using the unweighted pair group method with averages (UPGMA) tested by bootstrap (BS). Hybrid origin could not be easily confirmed in some regions. However, dendrograms constructed with a combined sequence analysis of A. triphyllum 26S ribosomal RNA gene [sequence identification (SI) 467] plus A. tortuosum phytochrome C-like (phyC) gene (SI 468) were very similar to dendrograms constructed from sequences of all regions. This suggests that selecting SI 467 and SI 468 would be practical to identify hybrid origins involving two parental species. Clustering of hybrids together with the female parent in most target regions suggests that, in Arisaema, cpDNA is considered maternally inherited.