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.     

Effektive Kontrolle des Braunrostes (Puccinia recondita f. sp. secalis Rob. ex Desm.) in Winterroggen mit Fungiziden unterschiedlicher Wirkstoffgruppen – Auswertung der Ringversuche der L?nder Brandenburg, Sachsen-Anhalt, Sachsen und Thüringen

To investigate different control measures against the diseases in winter rye several trials were done in the German federal states. As a result from these trials the brown rust,Puccinia recondita f. sp.secalis, was the disease with the most negative influence on the yield. The brown rust occurrence at different times on the top three leaves depend on the winter and spring weather. It should be verify whether the protective use of fungicide mixtures with the new carboxamides active ingredient benefits the curative use (disease onset) in terms of achieved efficiency againstP. recondita. It can be stated that the action threshold does not need to be changed when using fungicide mixtures with carboxamides. Regarding the duration of the fungicide efficacy againstP. recondita an order in increasingly levels of efficiency could be determinate. The order is, from lowest to highest, azole fungicides, strobilurin-azole compounds, azole carboxamide compounds, and azole-carboxamide strobilurin mixtures. Due to the variability in the values of the individual test sites in the experimental series the tendency could be confirmed, however, no statistical significant differences between the various mixtures could be determined. The new carboxamides enrich the possibilities of targeted anti-resistance strategy againstP. recondita in winter rye. These trials results are introduced into recommendations for agricultural practice.     

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.      

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.

     

Untersuchungen zur überlebensf?higkeit und Entwicklung der Larven zweier Herkünfte des Schwammspinners Lymantria dispar L. (Lep.: Lymantriidae) in Abh?ngigkeit von der Fra?pflanze

The polyphagous gypsy moth (Lymantria dispar) is able to feed on about 400 different woody plant species. In general, oak species are preferred – on the other hand some other groups of plants are avoided on account of the presence of toxic substances. These unfavoured hosts are, for example, most of the Papilionaceae, like locust (Robinia pseudoacacia). We compared survival rate and development of two populations of different origin with long-term habituation to oak and locust, respectively. Larvae from the population habituated to oak proved unable to develop on locust food. There must be a lack of detoxification systems to modify the toxic alcaloids and flavenoids produced by Robinia pseudoacacia. On the other hand, larvae isolated from an locust stand were able to feed on oak leaves without problems in larval development or eclosion of adults. Gypsy moth larvae specialized on locust as host showed increased mortality (up to 27%) in the early larval instars, but the surviving animals, especially female individuals, reached significantly higher pupal weights and showed better fecundity: 40% higher egg numbers/egg mass compared to those feeding on oak. These results indicate that the gypsy moth population originating from the locust forest had achieved a high level of metabolic adaptation to this host plant and formed a 'biotype' of Lymantria dispar with optimal reproductive conditions in this special habitat.     

Untersuchungen zur überlebensf?higkeit und Entwicklung der Larven zweier Herkünfte des Schwammspinners Lymantria dispar L. (Lep.: Lymantriidae) in Abh?ngigkeit von der Fra?pflanze

The polyphagous gypsy moth (Lymantria dispar) is able to feed on about 400 different woody plant species. In general, oak species are preferred – on the other hand some other groups of plants are avoided on account of the presence of toxic substances. These unfavoured hosts are, for example, most of the Papilionaceae, like locust (Robinia pseudoacacia). We compared survival rate and development of two populations of different origin with long-term habituation to oak and locust, respectively. Larvae from the population habituated to oak proved unable to develop on locust food. There must be a lack of detoxification systems to modify the toxic alcaloids and flavenoids produced by Robinia pseudoacacia. On the other hand, larvae isolated from an locust stand were able to feed on oak leaves without problems in larval development or eclosion of adults. Gypsy moth larvae specialized on locust as host showed increased mortality (up to 27%) in the early larval instars, but the surviving animals, especially female individuals, reached significantly higher pupal weights and showed better fecundity: 40% higher egg numbers/egg mass compared to those feeding on oak. These results indicate that the gypsy moth population originating from the locust forest had achieved a high level of metabolic adaptation to this host plant and formed a 'biotype' of Lymantria dispar with optimal reproductive conditions in this special habitat.     

P.D.A.

P.D.A.是三个英文字的缩写,P.=patato(马铃薯),D.=Dextrose(萄葡糖)A.=Agar(洋菜或称琼脂),是一种微生物培养基的代表符号。 不同种类的微生物,所要求的营养物质有差异,因此培养基的种类很多,P.D.A.是培养基中最常用的一种,适于植物病害中多种真菌、细菌的正常生长,因此又称普通培养基。     

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.     

C.d.a.–Controlled Droplet Application

Abstract

Efficiency of pesticide application can be improved if more consideration is given to where and when the active ingredient is most needed, and the optimum droplet size selected for a given target. Even when minimal volumes of spray are applied concentrate sprays are not justified as a greater proportion of the spray is collected on the target. Sprays with a narrow range of droplet size can be produced from ligaments thrown from centrifugal energy nozzles; droplet size being inversely proportional to the rotational speed.     

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.     

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.     

Die Verbreitung der Ro?kastanien-Miniermotte Cameraria ohridellaDesch. & Dimic (Lepid., Gracillariidae) in der Region Südtirol-Trentino

A survey on the present distribution of the horse chestnut leafmining moth, Cameraria ohridella Desch. & Dimic 1986, in Europe and in Italy is given: In Europe, within a period of 15 years, the leafminer – recently introduced into Central Europe – has settled in an area that spreads over 13 latitudinal and about 20 longitudinal degrees; in Northern Italy, an area of approximately 50,000 km² has been afflicted in the 5 years since the leafminer's introduction in South Tyrol and Julian Venetia in 1993.The development of the distribution in the region of South Tyrol and Trentino is shown: In the province of Bozen-South Tyrol, between 1995 and 1999 the moth has spread in all the three principal valleys (Eisacktal, Pustertal, Etschtal); in the Trentino province, first local attacks began only in 1998, near Trento and Riva, but spread over the entire Etschtal/Adige Valley in 1999. While in South Tyrol C. ohridella was introduced from the North (North Tyrol), the introduction into the Trentino occured from the South (Verona).At present the attacks in Trentino province are preponderantly low (resulting heavy only in the city of Trento and in Riva del Garda) and limited to altitudes ranging from 70 to 700 in. In South Tyrol, attacks are mainly heavy in altitudes ranging from 250 to 900/950 m, while they are low in the increasingly affected higher altitudes of 1,000 to 1,230 m. Numeric attack parameters are given to show attack intensities.The number of generations per year depends on the respective climatic conditions: in lower-altitudes, usually three generations develop in a year, but in higher altitudes (800 to 1,100 m) only two generations; in the climatically favoured area around the Lake Garda a (partial) fourth generation appears possible.The question of host plants (Aesculus sp., Acer sp.) and the larval parasitism of C. ohridella is discussed. The parasitism of the larvae, principally by Eulophidae (Hym., Chalcidoidea), was ascertained already in the first years of attack: In South Tyrol, 16 species of parasitoids appeared, and 8 in the Trentino province, but only two species were dominant: Minotetrastichus sp. and Pnigalio sp. The level of parasitism reached was low, comparable to other Central European countries.     

猪殃殃Galium aparine L.var.tenerum(Gren.et Godr.)Rchb.发生规律观察

猪殃殃是我省分布广泛,危害严重的麦田恶性杂草。近年来,发生数量和危害面积还在不断上升,是麦子增产的障碍之一。笔者从1979年秋播开始对其生物学特性和发生规律作了调查观察,现将观察结果简报如下: 一、分布特点猪殃殃的分布和土质有很大关系,据在本地区9个县46个公社调查1561亩麦田(代表面积一万七千余亩)每平方尺发生10株以上的危害面积,沙土地区占调查面积的12.2％,粘土     

B.t.乳剂防治蔬菜害虫技术

B．t．杀虫剂是由苏云金杆菌发酵生产的一种微生物杀虫剂，能在细胞内形成菱形伴抱晶体的芽抱杆菌。其伴抱晶体是一种强毒性蛋白，在昆虫中肠碱性环境下释放出后，可使昆虫瘫痪致死。芽炮也能在虫体内萌发繁殖，从而加速昆虫死亡。B．t．杀虫剂具有化学农药不可替代的优越性，其治虫效果好，对害虫天敌和作物安全，使害虫不易产生抗药性，对生态系统无不良影响等优点，是生物防治蔬菜害虫的首选杀虫剂。我县自1992年将B．t．应用于蔬菜害虫的防治，取得了良好的防治效果和效益。特别是应用干蔬菜地防治菜青虫、小菜蛾和棉铃虫等害虫，防治…