The side effects of lime sulphur on predaceous arthropods, i.e. Typhlodromus pyri, and other leaf occupying arthropods

Conclusions and further studies The significant reduction of T. pyri and of larvae of predaceous gall midges, the complete loss of mite-diversity and the possible enhancement of P. ulmi and other harmful mites (i.e. C. vitis) are clear disadvantages of lime sulphur. Densities of T. pyri between 0.5 and 1 mite per leaf as mentioned to be necessary for controlling harmful mites (BOURQUIN 1989, FORTMANN 1993, HARZER 1993, KARG 1992, KOHLER ET AL. 1991), were never reached in lime sulphur treatment, while the untreated control always showed densities above this value. On the other hand low densities of predaceous mites are quite normal in intensively sulphur treated, biological orchards and are often replaced by other mite predators, like predatory bugs (Miriadae, Anthocoridae) or the coccinellid beetle Stethorus punctillum (HÄSELI & BOSSHARD 1994). Therefore further studies should include these arthropods, because lime sulphur may also have adverse effects on them (BORIANI 1994, BROWN 1978). Furthermore the lowest application strategy in terms of frequency and concentrations for scab control should be examined to minimise the quantity of applied lime sulphur (ZIMMER 2000). In addition the effects of different application methods, for example by sprayer or overhead irrigation on beneficial arthropod as well as on scab should be studied (KELDERER ET AL. 2000). The side effects of lime sulphur should not be considered separated from other used fungicides, moreover the whole spraying program should be included, because wettable sulphur (MILAIRE ET AL. 1974) and clay powder (HÄSELI & BOSSHARD 1994) also harm arthropods. For agronomic interests but also from the points of view of the registration of lime sulphur and the public image of organic apple growing, the question is: whether lots of preventive applications with copper, sulphur and clay powder have more adverse effects on beneficial arthropods than fewer curative applications of lime sulphur by using an infestion prediction model. Only by further studies under realistic farming conditions it is estimable, whether the use of lime sulphur in organic orchards can be accepted. In the common enthusiasm about this new curative fungicide, we should not forget the important role of beneficial arthropods. In this context the registration without any indication in the EU should be critically discussed

Dynamics of a rational system of difference equations in the plane

We consider a rational system of first order difference equations in the plane with four parameters such that all fractions have a common denominator. We study, for the different values of the parameters, the global and local properties of the system. In particular, we discuss the boundedness and the asymptotic behavior of the solutions, the existence of periodic solutions and the stability of equilibria

Regulierung der Blutlaus (Eriosoma lanigerum) im Biologischen Apfelbau. Erfahrungen aus drei Versuchsjahren mit direkten und indirekten Verfahren

Einleitung 1997 trat die Blutlaus (Eriosoma /anigerum) in der Schweiz in verschiedenen Bioobstanlagen stark auf. Die Gründe dafür liegen wahrscheinlich in der ungenügenden Parasitisierung der Blutläuse durch die Blutlauszehrwespe. Zwei kalte Winter (1995/96 und 1996/97) aber auch die kühle und nasse Witterung im Mai und Juni 1997 haben die Entwicklung der Zehrwespenpopulationen stark eingeschränkt. Die Schaden waren vielfach enorm und führten nebst Fruchtverschmutzungen zu irreversiblen Trieb- und Knospenschaden, gefolgt von Ernteausfall im Folgejahr, bis zum Absterben ganzer Baume. Die Praktiker begegneten dem Übel mit Mineralölbehandlungen, Entfernung der Kolonien durch Abbürsten bzw. mit einem Hochdruck-Wasserstrahl oder mit viel Geduld für den Aufbau von Nützlingen wie Zehrwespe und Ohrwürmer. Der akuten Lage entsprechend führte das FiBL unter Mitwirkung der Firma Andermatt Biocontrol AG Versuche mit direkten und indirekten Maßnahmen durch

Classification of high dimensional data using LASSO ensembles

Urda, D., Franco, L. and Jerez, J.M. (2017). Classification of high dimensional data using LASSO ensembles. Proceedings IEEE SSCI'17, Symposium Series on Computational Intelligence, Honolulu, Hawaii, U.S.A. (2017). ISBN: 978-1-5386-2726-6The estimation of multivariable predictors with good performance in high dimensional settings is a crucial task in biomedical contexts. Usually, solutions based on the application of a single machine learning model are provided while the use of ensemble methods is often overlooked within this area despite the well-known benefits that these methods provide in terms of predictive performance. In this paper, four ensemble approaches are described using LASSO base learners to predict the vital status of a patient from RNA-Seq gene expression data. The results of the analysis carried out in a public breast invasive cancer (BRCA) dataset shows that the ensemble approaches outperform statistically significant the standard LASSO model considered as baseline case. We also perform an analysis of the computational costs involved for each of the approaches, providing different usage recommendations according to the available computational power.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec