Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen)最新文献

{"title":"The effect of adjuvants on atomisation of pesticides.","authors":"P Spanoghe,&nbsp;W Steurbaut,&nbsp;H Van Eeckhout,&nbsp;P Van der Meeren","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Four surfactants Tween 20, Agral 90, Silwet L77 and Break Thru, commonly used in the formulations of agricultural products, were evaluated on their spray performance and dynamic surface tension. In a spray test the Dv 50 (micron) or the Volume Median Diameter and the percentage of droplets with diameter below 100 microns (drift sensitive droplets), were measured for different kind of nozzles varying from the classical flat fan up to the low drift nozzles. The spectra changed considerably when different kind of nozzles and different kind of surfactants were used, the concentration effect was less important. The dynamic tension of the different surfactant solutions could not always explain the changes in droplet spectrum.</p>","PeriodicalId":85134,"journal":{"name":"Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen)","volume":"67 2","pages":"129-32"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22346432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rhizobacteria-induced changes in tomato metabolism and their relationship to induced resistance against Fusarium oxysporum f.sp lycopersici.","authors":"M Mwangi,&nbsp;R Hauschild,&nbsp;E W Mutitu,&nbsp;R A Sikora","doi":"","DOIUrl":"","url":null,"abstract":"","PeriodicalId":85134,"journal":{"name":"Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen)","volume":"67 2","pages":"145-7"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22346434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Toxicity of a mancozeb containing fungicide formulation and CU-sulphate to chicken embryos after administration as single compounds or in combination.","authors":"S Fejes,&nbsp;P Budai,&nbsp;L Várnagy,&nbsp;T Molnár,&nbsp;R Szabó,&nbsp;T Fáncsi","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Environmental pollution of metal modelled by copper-sulphate and a 80% mancozeb containing fungicide formulation (Dithane M-45) were studied on chicken embryos after administration as a single compounds or in combination. The test materials were injected into the air-chamber in a volume of 0.1 ml/egg on day 12 of incubation. The concentration of copper-sulphate was 0.01%. The applied concentration of Dithane M-45 fungicide formulation was 0.2%. Evaluation was done on day 19 of the hatching period. The combined administration of copper-sulphate and the fungicide formulation did not cause a significant reduction in body weight as compared to the control data and the results from individual toxicity study of the test materials. After the combined administration of copper-sulphate and the fungicide formulation the rate of embryomortality was 40%. The incidence of developmental anomalies were sporadic. Light microscopic findings exhibited a degenerative change in the liver tissue of combined administration group. Activities of GPT and GOT enzymes increased markedly in the combined administration group. In summary, it can be established that the interaction of copper-sulphate and an 80% mancozeb containing fungicide formulation (Dithane M-45) caused higher embryomortality with respect to the test of individual toxicity of copper-sulphate and fungicide in our study.</p>","PeriodicalId":85134,"journal":{"name":"Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen)","volume":"67 2","pages":"105-9"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22346528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Importance of sub optimal temperatures for the virulence of different geographical provenances of entomopathogenic fungus Verticillium lecanii (Zimm.) Viegas.","authors":"Natalja Hetsch,&nbsp;Helga Sermann,&nbsp;H Bochow","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The virulence of the tested strains was developed from environmental conditions. The strain V24 had a stable virulence at all temperature levels and achieved in relation to the other examined strains the highest mortality of infected insects. The other strains have shown different changes of effectiveness at the sub optimal conditions. Germination of blastospores was temperature depending and correlated in the mostly cases with the virulence.</p>","PeriodicalId":85134,"journal":{"name":"Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen)","volume":"67 3","pages":"591-9"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22342579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of water management and herbicide treatments on red rice control.","authors":"A C Sparacino,&nbsp;F Tano,&nbsp;R Ferro,&nbsp;D Ditto,&nbsp;N Riva,&nbsp;R Braggio","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Two field experiments were conducted in 1999 and 2000 at Zeme (Pavia, Italy) to determine the effects of water managements and herbicide treatments on red rice control. In the first experiment, all plots were flooded 10-13 cm deep from April 1 to May 17 in 1999 and from April 3 to May 6 in 2000. At the same time, in the second experiment, the plots were alternately drained-flooded. At the end of water management, all plots of both experiments were drained and sprayed with herbicides to control the emerged red rice plants. In both years were applied: Propaquizafop 78 g a.i.ha-1, Cycloxydim at 300 and 400 g a.i. ha-1; Dalapon at 15.300 Kg a.i. ha-1; Quizalofop-ethyl at 100 g a.i. ha-1. Six days after the chemical treatments, all field plots were flooded 10 cm deep and three days later, an early variety of rice (Loto) was sown at 150 Kg ha-1. Seedling emergence was reduced by lack of oxygen (especially from seeds covered with soil in flooded condition). In alternately drained-flooded soil, the red rice emerged and developed from seeds located in the top 4-5 cm. In flooded condition, no red rice plants emerged from seeds at more than 1 cm depth. In both experiments, the density of red rice plants increased during the season in the untreated check and in the plots where treatments were ineffective or performed poorly. The best red rice control, both in submerged and in alternately drained-flooded soil, was obtained with Quizalofop-ethyl (100 g a.i./ha), Cycloxydim (300 and 400 g a.i.ha-1) and Propaquizafop (78 g a.i.ha-1). These herbicides controlled 90-99% of red rice. Partial control of red rice resulted with the other chemical treatments. The shattered grains of red rice were reduced in both experiments by the herbicide treatments. Grain yield reflected the level of red rice control. In fact, the highest commercial grain yields were obtained with Quizalofop-ethyl, Propaquizafop, and Cycloxydim (400 g a.i.ha-1), in both years and experiments. The red rice percentages of the total yields resulted about 3.6-5.7% with all chemical treatments except Dalapon, which was not much effective.</p>","PeriodicalId":85134,"journal":{"name":"Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen)","volume":"67 3","pages":"441-9"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22342128","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preservation of an artificial diet for rearing the predator Orius laevigatus.","authors":"Y Arijs,&nbsp;L Vanthournout,&nbsp;P De Clercq","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The use of an artificial meat diet for Orius laevigatus lacking antimicrobial agents, resulted in rapid contamination of the medium especially by (unidentified) bacteria when stored in the rearing cages at 23 degrees C. Meat spoilage was detrimental for the insect and negatively affected the developmental parameters depending on the time between two feeding intervals. Two antibiotics (chortetracycline and gentamycin sulfate) were screened for their potential to extend the shelf life of the diet. The efficiency of the preservatives to control bacterial growth was tested by using a plate count method. Results showed that both agents were able to suppress growth of the bacteria in the diet but the sensitivity of the predator to 0.05% chlortetracycline was high: growth, survival rate and size of the insect were seriously affected by this antibiotic. When diet containing 0.05% gentamycin sulfate was left in the cages for 2 to 3 days, it yielded similar development to that on fresh antimicrobial-free diet. Gentamycin sulphate at a concentration of 0.05% can thus be considered as a safe antibiotic for O. laevigatus.</p>","PeriodicalId":85134,"journal":{"name":"Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen)","volume":"67 3","pages":"467-71"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22342130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Screening low fire blight susceptible Crataegus species for host suitability to hawthorn leaf-curling aphids (Dysaphis spp.).","authors":"E Bribosia,&nbsp;D Bylemans,&nbsp;G Van Impe,&nbsp;M Migon","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The group of hawthorn leaf-curling aphids (Dysaphis spp.) hosted by the common hawthorn Crataegus monogyna Jacq. may play an important role in the biological control of the rosy apple aphid, Dysaphis plantaginea (Passerini), by increasing reproduction opportunities for the indigenous hymenopteran parasitoid Ephedrus persicae Froggatt. Unfortunately, most fruitgrowers hesitate to introduce the common hawthorn in their orchards because they fear fire blight infections which may be transmitted by this highly susceptible hawthron species. This potential hazard led us to investigate the suitability to leaf-curling aphids of alternative Crataegus species. As representative for these closely-related aphids, the species Dysaphis apiifolia petroselini (Börner) was used in the trials. Ten Crataegus species characterized by their very low susceptibility to fire blight were examined from two angles. Firstly, aphid sexuals were introduced in autumn onto the different species to verify whether egg laying could take place. Secondly, the development of fundatrices and gall formation were followed the next spring. Although eggs and mature fundatrices could be obtained on almost all species, no fundatrice-hosting galls were recorded in spring. The possible causes of these negative results with respect to the geographical origin of the particular Crataegus species involved in this work are discussed.</p>","PeriodicalId":85134,"journal":{"name":"Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen)","volume":"67 3","pages":"473-80"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22342131","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microfungi on compositae in the Ruhr Basin.","authors":"N Ale-Agha,&nbsp;G B Feige,&nbsp;M Dachowski","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Forty-three microfungi have been observed on thirty species of the Compositae occurring in several locations in the Ruhr Basin in North Rhine-Westphalia. Many fungi belong to the Ascomycetes (Erysiphales, Diaporthales, Dothideales, Leotiales and Pleosporales) and to the Deuteromycetes (Melanconiales, Moniliales and Sphaeropsidales). Other fungi wich were found in our investigation belong to the Basidiomycetes (Uredinales) and to the Oomycetes (Peronosporales). Some recorded microfungi have been discovered on new hosts in North Rhine-Westphalia and also in Germany for the first time. New for North Rhine-Westphalia are Ascochyta spec. Libert on Matricaria recutita L., Phoma exigua var. linicola (Naumov & Vassilevski) Maas on Tripleurospermum maritimum (L.) W. D. J. Koch, Phomopsis achillea (Sacc.) Höhn. on Achillea ageratum L., Diaporthe aff. arctii (Lasch) Nitschke on Solidago canadensis L. and on Achillea ageratum L., Lophiostoma caulium (Fr.) Ces. & De Not. on Anthemis tinctoria L. and Ophiobolus fructicum (Rob. ex Desm.) on Serratula tinctoria L. New for Germany are Ophiobolus cirsii (P. Karst.) Sacc. on Cichorium intybus L., Phomopsis cirsii Grove on Cirsium vulgare (Savi) Ten., Pleospora kansensis J. P. Ellis & M. B. Ellis and Pleospora phaeocomoides cf. var. infectoria on Centaurea jacea L.</p>","PeriodicalId":85134,"journal":{"name":"Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen)","volume":"67 2","pages":"217-26"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22345695","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Understanding Puccinia striiformis West. epidemics on winter wheat.","authors":"Dimitri Lemaire,&nbsp;Stephanie Huret,&nbsp;Frederic Calay,&nbsp;Henri Maraite","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Yellow rust epidemics, caused by Puccinia striiformis West., often arise in wheat field as infection focus of a few decimetres of diameter, including some sporulating lesions on a few plants. Under appropriate environmental conditions such as high relative humidity and temperatures between 2 and 20 degrees C, those initial foci may grow rapidly and initiate new foci elsewhere in the field. The first aim of this work was to better understand the effects of weather parameters on the focus growth. An experiment was conducted in a wheat field during the 2001 season to measure, from inoculated plants, the disease progression related to climatic conditions (temperature, relative humidity, precipitations and wind). Three plots were inoculated in March and the sporulating lesions around each focus were monitored every week on 8 segments starting from the centre of the plot, by recording the infected leaf layers and the spatial position of every infected plant. Once established, the disease spread not only horizontally, by spore transport from plants to plants, but also vertically, by spore dispersal from lower leaf layers to upper ones. The focus required a build up period, with diseased plants confined to a circle of maximum 3 m diameter around the centre with the inoculated plants, before a widespread expansion. This initial build up period required at least two generations. On base of the changes of the disease status observed every week and the calculation of the latent period, the supposed infection dates and the environmental factors responsible for those infections were determined. This allowed adjustment of an infection forecasting model based on weather data. These results will be integrated into a decision support system to control the disease before the occurrence of large scale inoculum dispersion.</p>","PeriodicalId":85134,"journal":{"name":"Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen)","volume":"67 2","pages":"251-6"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22345698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strategies for biological system management of nematodes in horticultural crops: fumigate, confuse or ignore them.","authors":"Richard A Sikora","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Integrated management of nematodes as well as other soil-borne pests and diseases in horticultural crops in the tropics and subtropics as well as in protected cultivation in temperate climates is often a lopsided approach based on soil fumigation. With the upcoming loss of methyl bromide (Mbr), because of its effects on the ozone layer of the atmosphere, growers will have to make changes in the way they look at the problem of controlling soil-borne nematodes, fungi, insects and weeds. They can no longer rely on eradication of all pest problems with a one-stroke fumigation process. This is a severe problem that requires sound scientific solutions. New control technologies need to be developed and established methods urgently refined that are acceptable to the growers. Alternative fumigants and systemic nematicides still on the market will not provide broad spectrum control equal to Mbr. More disturbing is a provocative statement made by an economist that due to pesticides nematologists have neglected developing suitable alternative IPM measures of control. Some people may agree with this statement, especially if they are not involved in soil-ecosystem research. If you are a nematologist, this thought-provoking statement is at first upsetting but it is not valid. My talk will concentrate on the biological and cultural control methodologies that have been developed by nematologist around the world for use in management systems. These are technologies that can compensate for the loss of methyl bromide to horticultural crops in many countries. Alternatives are available and new methodologies are being developed for restructuring IPM strategies in many crops. The compatibility of these new approaches with general farming practices needs to be assessed on a country by country basis. Mutually interacting technology packages are needed, that are logically structured in \"biological system management\" programs that stress biocontrol aspects of control and not pesticides as is often the case in standard IPM approaches.</p>","PeriodicalId":85134,"journal":{"name":"Mededelingen (Rijksuniversiteit te Gent. Fakulteit van de Landbouwkundige en Toegepaste Biologische Wetenschappen)","volume":"67 2","pages":"5-18"},"PeriodicalIF":0.0,"publicationDate":"2002-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"22345951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}