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.     

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.     

Zum Auftreten der Robinien-Miniermotte,Phyllonorycter robiniella (Clem.) und der Ro?kastanien-Miniermotte,Cameraria ohridella Desch. & Dim. (Lep., Gracillariidae) in Südtirol

Zusammenfassung  An 2 Gracillariiden,Phyllonorycter robiniella undCameraria ohridella, wird gezeigt, wie rasch importierte Sch?dlinge sich ausbreiten k?nnen: Die RobinienblattmotteP. robinella wurde in Südtirol erstmals 1991 festgestellt und trat 1996 bereits in Massenbefall bei Brixen an Robinien auf.—Die Ro?kastanienminiermotteC. ohridella war hier erstmals 1992 im Pustertal bei Toblach festgestellt worden (Butin & Führer, 1994). Neueste Untersuchungen im Herbst 1997 zeigen, da? sie nun bereits im gesamten Eisacktal zwischen Franzensfeste und Bozen an Ro?kastanien (Aesculus hippocastanum) verbreitet ist (Tab. 1); hingegen wurde im Etschtal südlich und westlich von Bozen bisher noch kein Befall festgestellt.

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On the occurrence of the robinia-leafminer,Phyllonorycter robiniella (Clem.) and the horse-chestnut- leafminer,Cameraria ohridella Desch. et Dim. (Lep., Gracillariidae) in South Tyrol

The examples of two species of Gracillariidae,Phyllonorycter robiniella andCameraria ohridella, show how fast the expansion can take place: The robinia-leafminerP. robiniella was first noticed in South Tyrol in 1991 and an outbreak occured on False Acacias near Brixen, already in 1996.—The horsechestnut leafminerC. ohridella was first noticed in the Pusteria Valley near Toblach-Dobiacco, in 1992 (Butin & Führer, 1994). The latest research, of autumn 1997, shows that they are now distributed on Horse Chestnut Trees (Aesculus hippocastanum) in the whole Isarco Valley, between Fortezza and Bozen-Bolzano (Tab. 1), whereas in the Adige Valley at south and west of Bolzano no occurrence could be found as yet.

     

南美番茄潜叶蛾Tuta absoluta,a.幼虫及为害状,b.蛹,c.成虫,d.卵

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Erfahrungen bei der bek?mpfung der wanderratte,Rattus norvegicus (Berk.) 1999 in Magdeburg

Data of a pest control business was used to study infestation with the brown, or Norway rat (Rattus norvegicus Berkenhout, 1769]) in the City of Magdeburg for the year 1999. Swarms of rats were found to live all over the territory of the city. Blocks of residential buildings erected during G. D. R. times and, more specifically, their basements were noted to be focal sites of infestation with rats. The problem of rats living in the sewerage system of the city turned out to be unresolved. Detailed reference is made to rodenticides and active substances as well as to control strategies. The priority given to economical issues over the application of scientific findings is considered to be the decisive factor which accounts for the needs in the extermination of rats.      

Erfahrungen bei der bek?mpfung der wanderratte,Rattus norvegicus (Berk.) 1999 in Magdeburg

Data of a pest control business was used to study infestation with the brown, or Norway rat (Rattus norvegicus Berkenhout, 1769]) in the City of Magdeburg for the year 1999. Swarms of rats were found to live all over the territory of the city. Blocks of residential buildings erected during G. D. R. times and, more specifically, their basements were noted to be focal sites of infestation with rats. The problem of rats living in the sewerage system of the city turned out to be unresolved. Detailed reference is made to rodenticides and active substances as well as to control strategies. The priority given to economical issues over the application of scientific findings is considered to be the decisive factor which accounts for the needs in the extermination of rats.     

Host–pathogen interaction between Phytophthora infestans and Solanum nigrum, S. villosum, and S. scabrum

Potato and tomato are the two major hosts for Phytophthora infestans causing late blight. The susceptibility of leaves and whole plants of Solanum nigrum, S. villosum, and S. scabrum to infection by P. infestans was tested under laboratory conditions. Out of 39 plants representing 38 different S. nigrum accessions, 16 were highly resistant (seven accessions did not show any symptoms of infection, nine were highly resistant showing necrotic lesions in the place of infection), and 23 plants of S. nigrum were colonized by, at least, 1 of the 2 isolates of P. infestans (17 accessions were infected with two P. infestans isolates, and 6 accessions showed different reactions depending on the isolate used for inoculation). Three accessions of S. villosum, and one accession of S. scabrum were tested and did not show any symptoms of infection. The majority of S. nigrum accessions infected by P. infestans in a detached leaf assay were also infected in the whole plant assay. The reaction of field- and greenhouse-grown plants to inoculation with P. infestans in detached leaf assays was similar, but in some cases leaves from field-grown plants reacted as resistant in comparison with the leaves from greenhouse-grown plants, which were susceptible.     

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.      

Untersuchungen über Fichtengallenl?use, Dreyfusia spp. (Hom., Adelgidae) und deren Predatoren in der Nord-Türkei

In the East Pontic mountains at Giresun (Black Sea shore) three species of the genus Dreyfusia have been established: D. nordmannianae Eckst. and D. prelli Grosm. on Abies nordmanniana Link. and Picea orientalis Link. and Dreyfusia nov. spec. on A. nordmanniana. The latter species, earlier known from Greece and the Balkans, but not yet described is most probably unholocyctic on fir.In the Zigana mountains between Trabzon and Gümüsane a species producing plenty galls on young P. orientalis trees and closely resembling D. merkeri Eichh. has been observed. Further investigations are necessary to evaluate whether or not it lives unholocyclic on spruce.In the West Pontic mountains near Bolu D. nordmannianae was intensively studied in twig infestations on A. bornmülleriana Mattf. The pattern of attack differs greatly from the one experienced in central Europe in that almost exclusively the current year's shoots are attacked whereas the leader and the older twig axis remain free of attack. In Europe all parts of the trees are colonized.Considering the known facts about generation- and morph sequences, morph determination and phenological behaviour of D. nordmannianae the characteristics of their population dynamics in Turkey and the interactions of the curious mode of attack and the extraordinary efficiency of their special predators have been completely evaluated.     

Die ‘Stecklerberger Krankheit’, eine bisher nicht beobachtete Viruskrankheit der Sauerkirsche

Ohne Zusammenfassung     

“Zwartbenigheid” bij tulp en iris,veroorzaakt doorSclerotium wakkerii nov. spec.

Samenvatting Aansluitend op een vorige publikatie over de z.g. zwartbenigheid bij tulpen (Boerema, 1960) zijn in dit artikel nadere gegevens medegedeeld over deze ziekte en de veroorzakende schimmel. Een 23-tal bloembolgewassen zijn door uitplanting op zwaar besmette grond getoetst op hun gevoeligheid voor deze ziekte. Daarbij kon het typische ziektebeeld van de zwartbenigheid alleen worden verkregen bij tulpen en bolirissen. De uit de praktijk afkomstige stelling dat ook krokussen voor deze ziekte gevoelig zijn (Silver & Slootweg, 1959), kon niet worden bewezen.De kenmerkende eigenschappen van de sclerotiën vormende schimmel die deze zwartbenigheid veroorzaakt, zijn uitvoerig besproken. Daar de schimmel onbekend blijkt te zijn, is deze beschreven als een nieuwe soort:Sclerotium wakkerii. Deze schimmel is nauw verwant aanSclerotium denigrans Pape, die een zwarte verkleuring vanConvallaria-kiemen veroorzaakt (Pape, 1943).Summary After reference to an earlier paper on black leg of tulips (Boerema, 1960) the present paper gives further data on the disease and the causal fungus. Besides affecting tulips, the disease is also found in the field on bulbous irises. The disease symptoms are shown in figs. 1, 2, 3 and 4.The susceptibility to black leg of 23 bulb species was tested in heavily contaminated soil. In agreement with experience in practice, only tulips and irises developed the typical black leg symptoms. In other bulb species a black discoloration of the dead membraneous bulb or tuber tunic was sometimes found, but no disease symptoms appeared above ground. This applied also to crocus, for which susceptibility to black leg in the field has been claimed (Silver & Slootweg, 1959).The black leg-fungus is easily isolated on cherry agar at 20 °C (fig. 5a), after treating the attacked tissue with a detergent and rinsing with tap water. Growth of the fungus was studied on malt agar, as this medium favours good and rapid growth. The relation between the growth rate on malt agar in the dark and temperature is shown in fig. 6. In the early stage a white flat mycelium is formed; later this turns brownish-black, secreting a typical dark pigment in the medium (fig. 7a and 7b). The hyphae (fig. 5d) vary in width from 1.8 to 7.5 , the walls being rather thick, 0.4 to 0.8 . The hyphae are often anastomosed and branched. After 2 or 3 weeks in culture the fungus develops brownish-black round or flattened irregular sclerotia 2–5 mm in diameter and 0.5–1.5 mm thick, consisting of a compact mass of hyaline hyphae surrounded by thick-walled dark coloured cells (fig. 5a and 5c). When the fungus is grown at low temperatures sclerotia sometimes develop in the aerial mycelium. These are always somewhat spherical and at first white in colour (fig. 5b). In an old culture of the fungus grown on malt agar microconidia formed in phialides were found in 1960 (Boerema, 1960). This has not been observed again, however, so possibly a contamination was concerned.The black leg fungus differs from all other known sclerotia producing fungi.¹ It is therefore described as a new species,viz. Sclerotium wakkerii Boerema & Posthumus nov. spec. We take pleasure in naming this species after Dr.J. H. Wakker (1859–1927), originator of scientific work on bulb diseases. Living cultures of the fungus have been placed at the disposal of the Centraalbureau voor Schimmelcultures at Baarn (type culture) and at the Commonwealth Mycological Institute at Kew. Dried plate cultures were sent to the Commonwealth Mycological Institute at Kew and the Rijksherbarium at Leyden. Sclerotium wakkerii closely resemblesSclerotium denigrans Pape, the cause of a black discoloration of the shoots of lily of the valley (Pape, 1943). However, the sclerotia ofSclerotium denigrans are considerably smaller than those ofSclerotium wakkerii.