Permanence of soil surface crusts on abandoned farmland in the Central Ebro Basin/Spain

Surface crusts are frequently found on fallow land in the semi-arid Ebro Basin (Spain) and are an important factor in land degradation. Soil surface sealing leads to a decrease in infiltration rates and a consequent increase in runoff, thereby accelerating sheet wash and rill erosion. Thin sections were used to analyse the development and structures of the different crusts found across the ridge/furrow field pattern. Rainfall simulations experiments and infiltration measurements show the runoff generation and the soil erosion rates on the crusts. The spatial distribution of crusts was documented using large-scale aerial photographs, taken from a remote-controlled hot air blimp.     

Nematicidal potential of aqueous and ethanol extracts gained from Datura stramonium,D. innoxia and D. tatula on Meloidogyne incognita

Journal of Plant Diseases and Protection - The nematicidal effect of aqueous and ethanol extracts from leaves, roots and mixed plant parts...     

The drug transporter MgMfs1 can modulate sensitivity of field strains of the fungal wheat pathogen Mycosphaerella graminicola to the strobilurin fungicide trifloxystrobin

BACKGROUND: The major facilitator superfamily (MFS) drug transporter MgMfs1 of the wheat pathogen Mycosphaerella graminicola (Fuckel) J Schroeter is a potent multidrug transporter with high capacity to transport strobilurin fungicides in vitro. The data presented in this paper indicate that, in addition to the predominant cause of strobilurin resistance, cytochrome b G143A subsititution, MgMfs1 can play a role in sensitivity of field strains of this pathogen to trifloxystrobin. RESULTS: In a major part of field strains of M. graminicola (collected in the Netherlands in 2004) containing the cytochrome b G143A substitution, the basal level of expression of MgMfs1 was elevated as compared with sensitive strains lacking the G143A substitution. Induction of MgMfs1 expression in wild-type isolates upon treatment with trifloxystrobin at sublethal concentrations proceeded rapidly. Furthermore, in disease control experiments on wheat seedlings, disruption mutants of MgMfs1 displayed an increased sensitivity to trifloxystrobin. CONCLUSION: It is concluded that the drug transporter MgMfs1 is a determinant of strobilurin sensitivity of field strains of M. graminicola.     

Is there need for leaf-galling grape phylloxera control? Presence and distribution of Dactulosphaira vitifoliae in Swiss vineyards

Grape phylloxera (Dactulosphaira vitifoliae, FITCH) was a major pest in Vitis vinifera grape production in the late 19th and early 20th century in Europe. Roots of V. vinifera varieties are susceptible to D. vitifoliae attack whereas the leaves are not affected. The pest has been controlled by using American grapevine varieties as rootstocks. However, in recent years, grape producers have reported higher incidences of leaf galls induced by D. vitifoliae on V. vinifera leaves. Research on the occurrence of D. vitifoliae on grapevine leaves and roots has shown that D. vitifoliae is present in all wine-growing regions of Switzerland. In more than 80% of vineyards claiming to be infested, D. vitifoliae was found on leaves of varieties with interspecific crosses in their parentage. Three locations with leaf-galling individuals on V. vinifera were detected. D. vitifoliae individuals were found emerging from soil potentially associated with the commonly used rootstock varieties, which are assumed to be phylloxera tolerant. As climate change may necessitate the relocation of some viticultural areas to new wine-growing regions, there will be a greater need to control D. vitifoliae on leaves of interspecific crosses and the inspected planting material to limit further spread of the pest.     

Evaluation of anti-Ostertagia ostertagi antibodies in individual milk samples as decision parameter for selective anthelmintic treatment in dairy cows

The aim of this study was to explore whether anti-Ostertagia ostertagi antibody levels measured by ELISA in individual milk samples hold promise as a decision parameter for either herd-level decisions or selective anthelmintic treatments by investigating (1) the relationship between individual and bulk-tank milk ELISA results; (2) the relationships of individual milk ELISA results with non-parasitic cow factors and (3) the relationship between individual milk ELISA results and the milk production response after anthelmintic treatment. Twelve farms were randomly allocated to a whole-herd treatment with eprinomectin or a placebo in October 2004 and individual milk samples and a bulk-tank milk sample were collected 1 month before and 1 month after treatment. Linear mixed models were used to investigate the associations of ELISA results with (a) breed, actual milk production, lactation stage, somatic cell count, age and sampling month and (b) the milk production response after anthelmintic treatment. There was a reasonable correlation between the mean individual and bulk-tank milk ELISA results (r = 0.72). Individual cow ELISA results increased with higher lactation number and were lower in November than September. The associations with the other non-parasitic factors were weak and not significant. Milk yield responses to anthelmintic treatment were greater when treatment was given in early lactation and increased with the pre-treatment ELISA result and cow age. However, these latter two interaction terms were not significant when they were put in the model together. We conclude that (1) O. ostertagi ELISA results from individual milk samples may provide more information on the herd's parasitic status than a single bulk-tank milk result; (2) lactation number should be taken into account when interpreting ELISA results from individual milk samples and (3) the value of the O. ostertagi antibody level in individual cow milk samples to predict individual production responses after anthelmintic treatment remains equivocal.     

Verkapselung von bakteriellen Antagonisten und eines nematophagen Pilzes

Data and results are presented from a project on the development and application of hydrogel capsules for the delivery of two biological control agents, namely bacterial antagonists to control phytopathogenic fungi and a nematophagous fungus to control plant-parasitic nematodes. The focus is on encapsulation on lab and technical scales, drying and storage of the formulations, application to the greenhouse and field, and technology transfer to a biocontrol company.     

Zur Geschichte der Entdeckung des Reifungs-Anstieges im Gaswechsel von Obstfrüchten

Zusammenf assung Die Suche in der älteren Literatur nach bisher unbeachtet gebliebenen Beobachtungen über einen Reifungsanstieg im Gaswechsel von Kernobstfrüchten ergab:Der Reifungsanstieg im Gaswechsel von Obstfrüchten wurde bereits 1896 von Gerber für den Apfel dokumentiert aber übersehen, für die Banane jedoch auch beschrieben. Einige Jahre später beobachteten auch Müller-Thurgau & Schneider-Orelli (1908), daß das Ausmaß der CO₂-Ausscheidung von Äpfeln und Birnen im Verlauf ihres Wachstums bis zu einem Minimalwert absank. In diesem Zeitpunkt der minimalen CO₂-Ausscheidung gepflückte Äpfel und Birnen verstärkten im Verlauf eines ein- bis zweiwöchigen Lagerns bei Zimmertemperatur ihre CO₂-Ausscheidung auf etwa den doppelten Wert. Wurden die Äpfel erst einige Wochen nach dem Erreichen der Phase der minimalen CO₂-Ausscheidung gepflückt, so erfolgte der Anstieg der CO₂-Ausscheidung bereits auf dem Baum. Es wird geprüft, inwieweit die Autoren in diesen beobachteten Anstiegen der CO₂-Ausscheidung ein wesentliches, mit dem climacteric rise der englischen Forscher zu identifizierendes Reifungsphänomen erkannten.

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On the history of the discovery of the climacteric rise in gas exchange of pome fruits

In the older literature some observations concerning the gas exchange of ripening pome fruits have been found and discussed in this paper. These observations have been lost later on.The climacteric rise in gas exchange of apple fruits can be concluded from tables published by Gerber as early as 1896. Gerber himself did not recognize this phenomenon. In the case of the banana, however, he recorded and reported this rise in gas exchange during ripening.Some years later, Müller-Thurgau & Schneider-Orelli (1908), too, observed that the rate of the CO₂ output of apple and pear fruits diminishes to a minimal value during their growth period. Apple and pear fruits picked in this phase of minimal CO₂ output double the rate of their CO₂ output during the storage at room temperature for one to two weeks. If the apples are picked not before some weeks after having reached the phase of minimal CO₂ output, the rise in CO₂ output occurs already on the tree. Finally, it is discussed how far the authors have recognized that the observed rise in CO₂ output is an integer phenomenon of ripening for most of fleshy fruits. It is well known that this phenomenon is identical with the climacteric rise of the English investigators.