Influence of temperature,humidity duration and growth stage on the infection and mycotoxin production by Fusarium langsethiae and Fusarium poae in oats

High occurrence of Fusarium poae (FP) and Fusarium langsethiae (FL) and their mycotoxins nivalenol (NIV) and T-2/HT-2 have been observed in Swiss oats. Early prediction of mycotoxin levels is important for farmers and the cereal industry to minimize the risk of contaminated food and feed. Therefore, climate chamber experiments were conducted to investigate the influence of different temperatures (10, 15, 20 °C) and durations (4, 8, 12 h) at 99% relative humidity (RH) on the infection of oats with FP and FL. In addition, to discover the most susceptible period of oats, artificial FL inoculations were conducted at different growth stages. Field experiments were performed to observe the dispersal of these fungal species within the field and to investigate the weather conditions that influence the dispersal. The climate chamber experiments revealed higher contamination with NIV and T-2/HT-2 in the 10 °C treatments and with a prolonged humidity duration of 12 h 99% RH. Inoculations of oat plants at early (DC 61) and mid (DC 65) anthesis, led to higher FL infection and T-2/HT-2 accumulation in the grains compared with treatments at earlier growth stages, which might be due to an increased susceptibility during anthesis. No indication for spore dispersal was observed in the field experiments. The results obtained, together with the cropping factors that influence infection and mycotoxin production, could be used as a first step in developing forecasting models to predict the contamination of oats with the mycotoxins NIV and T-2/HT-2.     

Relationship of Icelandic cattle with Northern and Western European cattle breeds,admixture and population structure

ABSTRACT

Icelandic cattle is believed to have been brought from Norway during the settlement of Iceland around AD 870-930. Previous research on genetic relationships has indicated that Icelandic cattle is most related to northern Nordic indigenous breeds. Using single nucleotide polymorphism genotype data from Icelandic cattle and 29 Northern and Western European cattle breeds, we studied relationships and admixture among these breeds, and assessed population structure in Icelandic cattle. Population structure analysis through principal component analysis, estimation of ancestry, and analysis of patterns of population splitting and mixing revealed that Icelandic cattle are most related to three Finncattle breeds (Eastern, Northern and Western Finncattle), and Swedish Mountain cattle. Icelandic cattle has very low levels of admixture. We observed very limited population structure in Icelandic cattle. The observed structure was due to variable sire contributions. Over 1000 years of almost complete isolation has made Icelandic cattle highly genetically distinct from other cattle breeds.     

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Zur Möglichkeit des Einsatzes von Regulatoren des Pflanzenwachstums in der Schädlingsbekämpfung

Zusammenfassung In Anlehnung an ältere Untersuchungen mit holzigen Pflanzen ließ sich nun auch die Entwicklung von den krautigen Winterrapspflanzen durch eine Behandlung mit dem Wachstumsregulator Pydanon (Derivat der Pyridazinyessigsäure, 25 kg/ha) um etwa 2 Wochen verzögern.Im Durchschnitt der Versuche von 6 Feldern in 2 Jahren wurde durch diese Verzögerung die Populationsdichte der Kohlschotenmücke um fast 90% reduziert. Beim Kohlschotenrüßler betrug der entsprechende Wert 44%.Es werden die Ergebnisse, der kumulative Effekt von Herbiziden und Pydanon sowie die Ursachen der aufgetretenen Mindererträge diskutiert und die Voraussetzungen angedeutet, die für einen mehrjährigen Bekämpfungserfolg zu fordern sind.

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On the suitability of plant growth regulators for pest control

With reference to former investigations with wooden plants, the development of herbaceous winter rape could be retarded by treatments with the growth regulator PYDANON (derivate of pyridazinyl acetic acid, 25 kg/ ha) for about 2 weeks.In the mean of 6 fields in 2 years the population density of the brassica pod midge was reduced to about 90%. The respective value for the reduction of the cabbage seed weevil was 44%.The results, the cumulating effect between PYDANON and herbicides and the reasons for the observed yield reduction are discussed. Furthermore, the basic requirements are outlined, which are to be demanded for a control, lasting several years.

     

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Residue Reviews,Vol. 48

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Residue Reviews, Vol. 47