Auswirkungen des Herbizids Basta® auf die Weinrebe und den Falschen Mehltau

A field experiment was conducted in order to analyse the effects of the herbicide Basta^® with glufosinate-ammonium as the active ingredient (that inhibits specifically the enzyme glutamine-synthetase) on the grapevine plant and the infestation with Plasmopara viticola, the downy mildew pathogen. The herbicide was applied at sublethal concentrations and the toxic effects on leaves and berries based on different quality parameters were estimated. Low concentrations of glufosinate-ammonium (<?0,625?mM) did not affect the chlorophyll and amino acid concentrations in leaves. This was also the case for the content of salicylic acid and phenolic compounds. Furthermore, must parameters such as sugars (glucose and fructose), acids (tartaric acid, malic acid, total acids and volatile acids), and alcohol (ethanol and glycerine) also remained unchanged compared to the fungicide-treated or untreated control, whereas the concentrations of nitrogenous components metabolically available to yeasts increased with increasing concentrations of glufosinate-ammonium. The amount of berries harvested at the end of the experiment depended on the glufosinate-ammonium concentration applied. The harvest was highest when glufosinate-ammonium was applied as a 0.1?mM solution and differed not significantly from the fungicide-treated control, but decreased with increasing herbicide doses. However, the infestation of leaves with P. viticola was significantly reduced by the application of the herbicide, even though not each infection was eradicated due to the non-systemic mode of action of the herbicide. The particular influence of the herbicide onto this host-parasite interaction still remains unclear. Since applications of glufosinate-ammonium at low concentrations seem not to affect grapevine plants negatively, but were able to reduce the infestation with downy mildew, the specific mode of action may reveal new alternatives for the control of fungal pathogens.     

Mykotoxinbildung während der Infektion der Weizenähre durch den pathogenen Pilz Fusarium graminearum

Fusarium graminearum is one of the most destructive pathogens of cereals and a threat to food and feed production worldwide. Infection especially of wheat leads to yield losses and mycotoxin contamination. Deoxynivalenol is a hazardous mycotoxin inhibiting the biosynthesis of proteins. Its production by the fungus is a prerequisite for the colonization of the wheat spike. Combining molecular genetics with bioimaging techniques allows a fascinating insight into the pathobiology of this cereal pathogen.     

Einfluss der biologischen Bewirtschaftung auf die Phytodiversität in der Diasporenbank und oberirdischen Vegetation biologisch bewirtschafteter Ackerflächen

The project deals with the evaluation whether the conversion to organic farming leads to an increase of weed diversity. Additionally to the analysis of the above ground vegetation and the soil seedbank on the small permanent plots a mapping of the surrounding vegetation was conducted in 2012. The number of weed species varies highly over the years, but the inventory of species differs only slightly from the one found on the surrounding fields. The number of seeds per m² is highly correlated with the number of above ground weeds species. The crop has shown the highest influence on both.     

Wirkungsweise amorpher Diatomeenerden auf vorratssch?dliche Insekten. Untersuchung der abrasiven sowie sorptiven Effekte

The present study examined the morphological and physiological effects of amorphous diatomaceous earth against the stored product pestsS. granarius, T. molitor andT. confusum. Diatomaceous earth, namely Fossil Shield^? and Dryacide^? increased the mortality rate of this insects. After contact with Fossil Shield^? the individuals ofS. granarius had significant lost of weight and reduced their water content respectively. This showed that silica dusts break the water barrier of the cuticle. However, it increases the transpiration rate of water across the cuticle and the insect died past several times through dehydration. As well, an addition of food affected the effectiveness of dusts against insects. A lot of stored product beetles will be able to produce metabolic water of feed substrates. This ability protects and weaves contrary to the loss of water. Diatomaceous earth’s can be effective primarily through the sorptive properties of the hygroscopic particles. One day after dust treatment a significant weight loss ofT. molitor pupae was recorded. The exposure to the silica dust Fossil Shield^? caused partly an incomplete metamorphosis and death of the individuals. Pupae dipped in Fossil Shield^? or abrasive aluminium dust and rolled for further five minutes, reduced not significant higher their weight as unrolled exuvial stages. The morphological analyses of treated insects under the Scanning Electron Microscope showed, that the dust covered the hole integument. Partly, the silica particles sunk into the cuticle. After application of Fossil Shield^? at the cuticle of adults,T. molitor, did not show any wax layer. Also it could not be found once blocked by stigma of the mealworm. The dust particles accumulated around the respiration openings and they partly overgrew.      

Beitrag zum Sortentyp und Merkmalskennung der Reifedynamik durch den phänologischen Indikator, dem Silomais-Reifeindex

Data from the Central German variety trials was evaluated, to with the Silage maize Ripeness-Index (SRI) the off-ripe-specific type in its significance and impact on selected parameters of the quality, the yield of silage and energy maize, as well as the appropriate feeding of ruminants with rations of higher maize proportions. The characterization of the ripe type on the basis of SRI is closely associated with statements to maize ripening, reproducibility of variety performance, site suitability and environmental conditions of production in the context of the Dynamic Ripening and Analysis system (DRA). The environmental stability of maize varieties characterizes the type of variety that exerts a dominant role over the ripeness level on the production of silage maize. The difference between type and productivity as well as feed value was demonstrated. For a location and physiological ruminant feeding of maize in relation to the type are been conclusions in the field of plant health, ground feeding uptake, structure impact and physiological grain hardness. As a result of this evaluation a comprehensive advantage of the environment stable variety type with slow ripening maize (residual) plant is to determine which cannot be evidenced and used with the present system of ripeness of use-specific classification.     

Untersuchungen zum notwendigen Maß bei der Anwendung von Pflanzenschutzmitteln in Winterweizen in den Jahren 2004 bis 2016

In order to provide recommendations for future cropping systems with regard to the necessary minimum of pesticide use, a long-term field trial at the field site in Dahnsdorf of the Julius Kühn-Institute was conducted in the years 2004 to 2016 to investigate possible reduction of pesticides, taking into account the general principles of integrated pest management (Strategies to reduce the use of plant protection products). Two winter wheats (WW1 and WW2) were part of the crop rotation with six components and different quality classes (A wheat (WW1) and E wheat (WW2)) and resistance levels to important wheat pathogens. In all years, herbicides and fungicides were needed to control weeds and fungal pathogens due to the excess of the control threshold. Insecticides were only necessary in two years. When considering the treatment frequency index (TFI), the mean overall TFI varied with 2.6 in WW1 and 3.5 in WW2, but was significantly lower compared to practice. There were also differences in the mean fungicide TFI of the two crop rotation elements with 1.1 in WW1 and 1.6 in WW2 due to their different resistance level to important fungal pathogens. The same is true with regard to the herbicide TFI with of 1.1 in WW1 and 1.3 in WW2. The treatments in the strategies 2, 3 and 4 mostly resulted in significantly higher yields compared to the non-chemical strategy 1, which can be attributed to the strong weed and fungal infestations in strategy 1 and the good efficacy of the used plant protection products. The tended differences between strategy 2 with a situation-related application rate and the 25 and 50% reduced application rates in strategies 3 and 4, respectively, were not significant. A reduced application rate showed no negative long-term effects on weed emergence even after 13 years, but increased emergence numbers in strategies with reduced herbicide use. The results show that plant protection products savings are possible without significantly reducing yields. However, this requires a high level of human resources for monitoring and scoring the consistent observance of the principles of integrated pest management, such as the consideration of good crop rotation, the cultivation of resistant cultivars and the optimally coordinated treatments after the control threshold has been exceeded.     

Monitoringergebnisse der Schnellk?fergattung Agriotes (Elateridae, Coleoptera) in den Jahren 2008 bis 2010 in Rheinland-Pfalz

During the years 2008 to 2010 beetles of the genus Agriotes were monitored by means of pheromone traps in Rhineland-Palatinate. Each trap contained the female sexual pheromone of either Agriotes obscurus, A. sordidus, A. lineatus, A. sputator, or A. ustulatus. Beetles of these species could be caught, additionally also specimens of the species A. gallicus, A. acuminatus, and A. pilosellus. Specimens of A. brevis and A. proximus could not be caught, not even in traps with pheromones according to their species. The high frequency of A. sputator in the Upper Rhine Valley and mild river valleys was surprising. This might be an explanation for the increasing damages especially in potatoes during the past seven years. Also the species A. ustulatus occurred mainly in the Rhine Valley. The species A. obscurus was found predominantly in higher altitudes, A. lineatus and A. sputator appeared in the whole area, with varying frequencies. In all, we could determine the composition of Agriotes-species in 27 fields. In two fields traps were exposed in two subsequent years, in one field in three years. The changes in the populations are shown. The beetles collected in some fields were compared with the according wireworms.     

In vitro-Untersuchung einer möglichen fungistatischen Wirkung des Sekrets der Weinbergschnecke (Helix pomatia,Helix aspersa) auf Botrytis cinerea

In viticulture practices, technical cultivation practices and application of fungicides, specifically named botryticides, are important to control the grey mold, Botrytis cinerea. While conventional disease control is based upon applications of fungicides, options for controlling of grey mold in organic viticulture is limited. Resistance of the fungus and multiple drug resistance (MDR) require development of new disease control strategies. In vivo observation showed a reduced grey mold infection of grapes if covered with slime from garden snail. Hence, snail slime, commercial lectin (Helix aspersa agglutinin, HAA) from garden snail and bacteria isolated from snail slime were tested for antifungal or antagonistic activities against B. cinereain vitro. Furthermore, fluorescein isothiocyanate labeled Helix-lectin (FITC-HPA) was used to detect terminal N?acetyl-galactosamine residues (GalNAc) on fungal cell wall surface. In our experiments, neither slime (after sterile filtration) nor commercial lectin nor slime bacteria were found to affect spore germination and mycelial growth. Binding of lectin was found to depend on media and age of the fungal mycelium.     

Prognose von Wühlmaussch?den in Forstkulturen

Zusammenfassung  In den Jahren 1980–1990 wurden auf insgesamt 100 Probefl?chen Wühlmausf?nge für die Schadensprognose in Forstkulturen durchgeführt. Die gefangenen Tiere wurden im Labor eingehender untersucht und verschiedene Parameter mit der Dichteentwicklung der Schadnager verglichen. Für einen beschr?nkten Zeitraum von etwa 3 Monaten war die ?u?erlich me?bare L?nge der m?nnlichen Gonaden mit der Populationsentwicklung korreliert. Bei einer mittleren L?nge der Testes über 3,5 mm wurde eine Zunahme der Populationsdichte beobachtet (Gradation). Bei einer geringeren Gonadenl?nge war die Populations-entwicklung rückl?ufig (Retrogradation). Dieser Zusammenhang kann für eine Schadensprognose bedeutsam sein.

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Predicting damages of voles in forest cultivations

Voles like the Field VoleMicrotus agrestis, the Common VoleM. arvalis, the Bank VoleClethrionomys glareolus and the Water VoleArvicola terrestris can cause severe damages in forest cultivations by gnawing the trunks and the roots of the young trees. Damages occur during winter time when the population density of these species is high and food resources are limited. The forecast of the development of vole populations is needed to prepare countermeasures against vole damages. The increase or decrease of a vole population can be predicted, if the fertility of the caught specimens is observed. The gonadal size of the males was a suitable predictor for the trend of the development of a vole population. The change of population density of the Bank Vole in a time interval of 3 month (September–December) was highly correlated (r=0.86) with the gonadal index of males. The percentage of pregnant or lactating femals was also a good indicator, but less suitable for practical use. It is assumed, that the hormones of the hypophysis like FSH, LH and Prolactin rule the growth of the gonads, the fertility and the reproduction in a vole population. Testis size is an indicator for the activity of these fertility hormones and for the reproductive process. It can be used to predict the development of vole populations for a limited time interval.

     

Erarbeitung eines Testverfahrens zur Bestimmung der Protektiv- und Kurativleistung von Fungiziden bei der Bek?mpfung des Erregers der Stemphylium-Laubkrankheit Stemphylium botryosum in der Spargelkultur (Asparagus officinalis L.)

The foilage of Asparagus officinalis L. has a large contact surface for different leaf diseases, which can lead to profits cuts, especially by the causal pathogen of Stemphylium leaf spot, Stemphylium botryosum. The maintaining healthy of the foliage is an important precondition to achieve an optimal harvest in the following year. Therefore, it is necessary to describe the efficacy of currently approved plant protection products against S. botryosum in order to optimize the fungicide applications. In the context of greenhouse trials with asparagus seedlings a method should be developed to evaluate the preventive and curative efficacy of fungicides. At the beginning, stable, repeatable and homogeneous infections of S. botryosum needed to be achieved. Ad hoc the factors plant age (weeks after sowing date), inoculum (density of conidia per ml and concentration of malt), infection conditions (period of high relative humidity) and day of rating, as well as their influence on the occurrence of the symptoms, were investigated. With the exception of the factor plant age, the other factors had a significant effect on the infection. For the trials to evaluate the efficacy of fungicides, the analysed factors were defined. The age of the seedlings was six weeks after sowing, the inoculum was composed of 1,00?×?10⁵ conidia per ml combined with an 0,5% malt concentration, as infection condition the ??tunnel system?? with periodically high relative humidity was chosen. 13 days past infection was the optimal day of rating. To apply the seedlings with the fungicides, the registered application rate was reduced to 1/5. The trials to evaluate fungicides were conducted with the fungicides Signum^®, Rovral^® WG and two different testing agencies. At four consecutive application days, the plants were covered with fungicides. In the following, the infestation degree of stems in percent was evaluated. Additionally, the used S. botryosum-Isolates were biomolecularly investigated and the QoI- and SDHI resistance state determined.     

Auswirkungeh einer frosfspannerbek?mpfung auf die bodenfauna eines elchertwaldes

Studies were made in 1998 and 1999 In an oak forest (“Meuenburger Holz”) in Northern Germany for the purpose of testing the effect of some insecticides on the soil fauna. The preparations “Fastac” (active agent:a-Cypermeth-rin) and “Foray 48 B” (active agent:Bacillus thuringiensis var.kurstaki) were used for the control of winter moths (Operopbthera brumata). The insects and spiders were caught using the following methods: soil samples, pitfalls and net sweeps. There were differences In the spectrum of species and In the density of individuals between the three experimental areas, but these did not depend on effects of the used insecticides.     

Silikate im Pflanzenschutz: Elektrostatische Applikation und Abhängigkeit der Wirksamkeit von der Schichtdicke

Natural occurring amorphous silica is ubiquitous on the earth in soils and sediments. Both, natural derived silica and synthetically produced amorphous silica are used against stored product pests and parasites in animal houses. New formulations, active even under higher relative humidity's can be possible used against horticultural arthropod pests. Since many horticultural pests hide on the undersides of leaves and silica is a physical contact insecticide, an appropriate application method is needed. This paper reviews electrostatic application of natural derived amorphous silica to Brassica chinensis leaves. Due to the inherent high volume resistivity of silica powder, induction charging was ineffective for electrostatic powder coating. Corona charging involves a reliable current source, but typically is inefficient in charging the powder particles and creates a high density of free ions between the gun and grounded substrate as well as within the coating layer. These factors resulted in poor coating quality and inefficient particle deposition. The best leave coating was archived using tribo charging. Here we have been able to apply coatings with different thickness. While a silica coating of 25–50?μm in petri dish experiments resulted in a reduced mortality of the granary weevil, Sitophilus granarius (L.), there was no difference between mortality with coatings of 50–100?μm and 100–125?μm. Silica applications on B. chinensis leaves resulted within two hours in a 45% reduction of the CO₂-absorption. Absorption level stayed reduced over a period of seven days and was between 45 and 73% compared to the control. Even after removing silica dust using pressurized air CO₂-absorption was between 19 and 28% reduced. This might be the case because silica particles where so small that they could possible clog the stomata opening resulting in a reduced transpiration and photosynthesis rate.     

Extremwetterlagen und Auswirkungen auf Schaderreger – extreme Wissenslücken

Climate Change is likely to increase the frequency, intensity, spatial extent, duration and timing of weather and climate extremes and can result in unprecedented extremes. Managed systems like agriculture are not immune to them. Studying the rapidly growing body of climate change literature it has been noted that there are only a few papers concerning the influences of extreme weather on agriculture. Projections of future impacts of extreme weather cannot always be made with a high level of confidence. Pests (weeds, insect pests and plant pathogens) represent a major constraint to crop production. The present paper analyses scientific literature published since 1945 concerning the knowledge about the influences of extreme weather on incidence of pests in wheat, barley, maize, beet, potato, rape, forage crops and grassland. Only 63 papers were found. Insect pests and plant pathogenic fungi of maize and wheat are most investigated. The most papers describe the influences of drought, dryness heat and heavy down pours. There are enormously knowledge gaps. On the basis of this it is not possible to assess the influences of weather extremes in a changing climate on pests and yield loss current. More research in this field is needed urgently.     

Auswirkungeh einer frosfspannerbek?mpfung auf die bodenfauna eines elchertwaldes

Studies were made in 1998 and 1999 In an oak forest (“Meuenburger Holz”) in Northern Germany for the purpose of testing the effect of some insecticides on the soil fauna. The preparations “Fastac” (active agent:a-Cypermeth-rin) and “Foray 48 B” (active agent:Bacillus thuringiensis var.kurstaki) were used for the control of winter moths (Operopbthera brumata). The insects and spiders were caught using the following methods: soil samples, pitfalls and net sweeps. There were differences In the spectrum of species and In the density of individuals between the three experimental areas, but these did not depend on effects of the used insecticides.      

AEP – Eine automatische Entscheidungshilfe-Software für den integrierten Pflanzenschutz

A decision support software for greenhouse plant protection has to meet several requirements in order to be accepted and applied by growers. It should comply with the different operational needs of growers and should be helpful for inexperienced growers but also optimize plant protection strategies for experienced ones. Additionally a large number of cultures and pests should be covered and implementation of new crops, beneficials, pests and insecticides must be easy. Also handling should be easy and time saving. All software parameters should be adaptable to grower specific needs. The program should not decide on the control regime but rather give recommendations and provide data storage to optimize plant protection strategies. Thereby learning effects are stimulated and motivation to adapt decision processes in plant protection practice is increased.In this article we show the structure of a decision support software (AEP—Automatische Entscheidungshilfe für den integrierten Pflanzenschutz unter Glas) and describe its functionality for the model system tomato (Solanum lycopersicum)–whitefly (Trialeurodes vaporariorum)–natural enemy (Encarsia formosa).     

Arbeitsergebnisse aus der Projektgruppe ?Krankheiten im Getreide“ der Deutschen Phytomedizinischen Gesellschaft e. V.

In den Jahren 1989 bis 1992 wurde in bundesweit durchgeführten Feldversuchen eine Bekämpfungsschwelle für Blatt- und Ährenkrankheiten in unterschiedlich widerstandsfähigen Winterweizensorten überprüft. Nach vergleichbarem Muster lief die Überprüfung verschiedener Schwellenwerte in Winterroggen, Winter- und Sommergerste von 1992 bis 1995 ab.Mit von 1995 bis 1998 ebenfalls mehrfaktoriell angelegten Feldversuchen beteiligte sich die Projektgruppe an dem Vorhaben der Bundesanstalt für Landwirtschaft und Ernährung (BLE) Untersuchungen zum Einfluss unterschiedlicher Pflanzenschutzmaßnahmen auf den Mykotoxingehalt und den Fusarium-Besatz im Erntegut von Getreide (1997–2000). Ergänzt um Beiträge der Projektgruppenteilnehmer aus dem eigenen Forschungs- und Entwicklungsbereich wurden die Erkenntnisse der Projektgruppe zu diesem Themenkomplex im Rahmen eines Workshops im November 2002 vorgestellt und mit ca. 120 Fachleuten aus Ministerien, der Produktionstechnik sowie den vor- und nachgelagerten Bereichen diskutiert.     

Eignung verschiedener Anbaumedien f??r den erdelosen Subsistenzanbau in Iquitos (Peru) und deren Wirkung auf Wachstum und Qualit?t von Pfl??cksalat (Lactuca sativa L. var. crispa L.)

Peruvian nutritional indicators demonstrate, in particular for the underprivileged groups in remote regions, as in Iquitos, a malnutrition caused by the insufficient uptake of vitamins and mineral nutrients. Promoting cultivation and consumption of vegetables shall counteract this situation, but unfavourable tropical conditions complicate local crop growing in Iquitos. Due to transportation by air, in Iquitos imported vegetables are expensive goods and thereby prohibitive for many people. Soilless cultivation techniques represent an opportunity to cultivate high-value crops throughout the year on a regional basis. By the use of simplified methods, this technique also offers the underprivileged population the means to provide themselves with healthy vegetables. In the present study, regional available cultivation media were tested for simplified soilless cultivation in Iquitos. The characteristics of one substrate-less cultivation method based on a nutrient solution and eight different types of substrates, derived from the base substrates rice husks, gravel, sand and composted saw dust were compared. Using the example of Lactuca sativa L. var. crispa L. ??Grand Rapids??, general and physico-chemical characteristics of the nine cultivation media and their influence on crop developing and crop quality were determined. Results show that rice husks also gravel-sand-mix 2:1 and 1:2 are particularly suitable for soilless cultivation of loose leaf lettuce in Iquitos. Using these substrates, lettuce showed the best growth of shoots and roots and the highest yield. The crop quality was high for all tested cultivation media. If high weight and cost of the mineral substrate is not assessed negatively, it could also be used for plant breeding. It is to be assumed that a combination of rice husks and gravel-sand-mix is advantageous, since an optimised substrate weight and an improved water-air balance are to be expected.     

Arbeitsergebnisse aus der Projektgruppe „Krankheiten im Getreide“ der Deutschen Phytomedizinischen Gesellschaft e. V.

Zusammenfassung In den Jahren 1989 bis 1992 wurde in bundesweit durchgeführten Feldversuchen eine Bekämpfungsschwelle für Blatt- und Ährenkrankheiten in unterschiedlich widerstandsfähigen Winterweizensorten überprüft. Nach vergleichbarem Muster lief die Überprüfung verschiedener Schwellenwerte in Winterroggen, Winter- und Sommergerste von 1992 bis 1995 ab.Mit von 1995 bis 1998 ebenfalls mehrfaktoriell angelegten Feldversuchen beteiligte sich die Projektgruppe an dem Vorhaben der Bundesanstalt für Landwirtschaft und Ernährung (BLE) Untersuchungen zum Einfluss unterschiedlicher Pflanzenschutzmaßnahmen auf den Mykotoxingehalt und den Fusarium-Besatz im Erntegut von Getreide (1997–2000). Ergänzt um Beiträge der Projektgruppenteilnehmer aus dem eigenen Forschungs- und Entwicklungsbereich wurden die Erkenntnisse der Projektgruppe zu diesem Themenkomplex im Rahmen eines Workshops im November 2002 vorgestellt und mit ca. 120 Fachleuten aus Ministerien, der Produktionstechnik sowie den vor- und nachgelagerten Bereichen diskutiert.Darüber hinaus wurden in verschiedenen Redaktionsgruppen Bekämpfungsschwellen harmonisiert (1996) und Umfrageergebnisse zu den Ursachen der Entwicklung einer Fungizidresistenz (2001) sowie zum regionalen Ausmaß unterschiedlicher Vorfrüchte und Bodenbearbeitungsverfahren zu Winterweizen im Zusammenhang mit dem Komplex Ährenfusariosen/Mykotoxine (2002) bearbeitet.Als weitere Schwerpunkte wurden Gaeumannomyces graminis, Saatzeitversuche in Winterweizen sowie nichtparasitäre und Ramularia-Blattflecken behandelt. Die Frage nach möglichen Auswirkungen der ab 01.01.2005 gültigen EU-Agrarreform, des Pflanzenschutzmittelreduktionsprogramms der Bundesregierung und des Klimawandels auf den Pflanzenschutz wird aufgeworfen.