Feeding Sites Of Sitona Hispidulus Larvaw As Infection Foci For Fusarium Oxysporum F. Sp. Medicaginis In Alfalfa Roots,
2025
USDA, Agricultural Research Service
Feeding Sites Of Sitona Hispidulus Larvaw As Infection Foci For Fusarium Oxysporum F. Sp. Medicaginis In Alfalfa Roots, K T. Leath, A A. Hower
IGC Proceedings (1977-2023)
Fusarium wilt of alfalfa (Medicago sativa L.) was first described in 1927 (Weimer, 1928) in the United States and has since been reported from many other areas of the world. The causal agent is Fusarium oxysporum Sehl. f. sp. medicaginis (Weimer) Snyd. & Hans. Shoots of infected plants become yellow and wilt ; often only one side of the plant is affected. The outer root xylem tissue turns reddish brown, and infected plants usually die within one season (Leath et al., 1988). The fungus is soil-borne, survives in organic debris, and can persist up to 10 years as chlamydospores …
Non-Chemical Control Of Some Disease And Pests In Red Fescue And Kentucky Bluegrass Seed Production,
2025
Grassland Research Station, CSSR
Non-Chemical Control Of Some Disease And Pests In Red Fescue And Kentucky Bluegrass Seed Production, B Cagas
IGC Proceedings (1977-2023)
Diseases and pests are one of the main problems in grass seed production in Czechoslovakia. The silver top (white head) caused by the bug Leptopterna dolobrata L. and the ergot [Claviceps purpurea (Fr.) Tu!.] have an effect upon seed quantity and quality. In some years the leaf diseases (rusts, powdery mildew, spots) can play an important role in the seed ripening. The chemical control may leads to some problems. The effect of burning in two different periods (summer, spring) and the close cutting were compared in red fescue (Festuca rubra L.) and Kentucky bluegrass (Poa pratensi …
White Clover Yield, Quality, And Persistence : Insecticide, Fungicide, Nematode, And Virus Effects,
2025
USDA, Agricultural Research Service
White Clover Yield, Quality, And Persistence : Insecticide, Fungicide, Nematode, And Virus Effects, G A. Pederson, G L. Windham, M M. Ellsbury, M R. Mclaughlin, R G. Pratt, G E. Brink
IGC Proceedings (1977-2023)
White clover (Trifolium repens L.) is the most important forage legume for perennial pastures in the southeastern United States. Commonly, white clover stands decline within 2 to 3 years after seeding. This decline has been reported to be due to many factors including fungal diseases (Graham et al., 1961 ; James et al., 1980) insects (Graham et al., 1961 ; James et al., 1980), viruses (Kreitlow et al., 1957; Barnett and Gibson, 1977), and root-knot nematodes (Baxter and Gibson, 1959). No studies have evaluated effects of combinations or interactions of these factors on white clover growth in the field. …
La Lutte Contre Les Rouilles Du Ray-Grass Anglais Porte-Graine,
2025
FNAMS
La Lutte Contre Les Rouilles Du Ray-Grass Anglais Porte-Graine, H Clinkspoor, G Sicard
IGC Proceedings (1977-2023)
Les cultures de ray-grass anglais porte-graine couvrent environ chaque annee en France 2800 hectares, soit un peu mains de 20 % des surfaces nationales toutes graminees confondues. Une enquete realisee sur l'etat sanitaire de ces cultures avait revele qu'elles sont souvent attaquees par des rouilles au debut de l'ete. Quatre rouilles peuvent ainsi etre rencontrees : la rouille couronnee provoquee par Puccinia coronata est la plus frequente ; la rouille noire (P. graminis), la rouille brune (P. loliina) et la rouille jaune (P. striiformis) peuvent egalement se rencontrer. En conditions climatiques favorables, Jes cycles d'infection …
A Multi-Disciplinary Approach To Anthracnose Diseases Of Stylosanthes In Australia,
2025
CSIRO
A Multi-Disciplinary Approach To Anthracnose Diseases Of Stylosanthes In Australia, D F. Cameron, S Chakraborty, R D. Davis, L A. Edye, J.A G. Irwin, J M. Manners, I B. Staples
IGC Proceedings (1977-2023)
Breeding Stylosanthes for resistance to anthracnose diseases in northern Australian pastures is complicated by extensive pathogenic variation in the fungal pathogen, Colletotrichum gloeosporiodes. We have put considerable emphasis on epidemiological studies in an attempt to devise optimal strategies for the use of resistance genes in our selection and breeding programs. In addition, techniques of molecular biology are being used to investigate prospects for the use of genes from novel sources and to study the genetics of virulence in the pathogen.
Breeding For Resistance To Bacterial Wilt Of Grasses (Xanthomonas Campestris Pv. Graminis),
2025
Federal Agricultural Research Station, Changins
Breeding For Resistance To Bacterial Wilt Of Grasses (Xanthomonas Campestris Pv. Graminis), D Schmidt
IGC Proceedings (1977-2023)
Bacterial wilt of fodder grasses caused by Xanthomonas campestris pv. graminis was first described by Egli et al. (1975), and since then observed all over Europe and in New Zealand. The regular mowing of the crop offers ideal conditions for spreading of the pathogen. Several grass species are affected. The most severe yield losses occur in Lolium multiflorum, particularly in var. westerwoldicum. In extreme cases, all the plants can be killed during hot, dry summers. Gondran and Betin (1988) found up to 47 % of yield loss in the three cuts following inoculation of Italian rye-grass cultivars. Losses are less …
L’Anthracnose De La Luzerne Dans Le Maroc Oriental Resistance De Quelques Cultivars Et Lignees,
2025
Faculte des Sciences, Oujda
L’Anthracnose De La Luzerne Dans Le Maroc Oriental Resistance De Quelques Cultivars Et Lignees, Huguette Gosset, B M. Troeung, G Raynal
IGC Proceedings (1977-2023)
Dans le Maroc oriental (regions d'Oujda, Berkane, Ai:n Beni Mathar), la luzerne (Medicago sativa L.) ne peut etre cultivee que dans les zones irriguees, en raison de l'aridite du climat. Dans ces conditions, elle est exploitee pour le fourrage tous les 20 jours au printemps et en ete et tous les 30-40 jours en automne et en hiver. La variete largement utilisee actuellement est Moapa dont les cultures, lorsqu'elles sont saines, durent 5 ans. Des prospections nous ont montre que de nombreux problemes sanitaires existent. C'est ainsi que l'anthracnose (Colletotrichum trifolii Bain et Essary) apparait comme !'affection fongique predominante …
Diachorella Leaf Spot Of Prairie Milkvetch In Loess Plateau, China,
2025
Chinese Academy of Agricultural Sciences
Diachorella Leaf Spot Of Prairie Milkvetch In Loess Plateau, China, Hou Tianjue, Wang Jiangfeng
IGC Proceedings (1977-2023)
Prairie Milkvetch (Astragalus adsurgens), an acclimatized good sand binder, soil and water conservation legume forage plant, cultivated widely in the arid and semi-arid districts of North China, is especially suitable for the Loess Plateau, China. Unfortunately in the mid Inner Mongolia, North Shaanxi Province and the eastern part of Gansu Province, it is often infected seriously with Diachorella leaf spot (Diachorella lathyri Fckl.). The disease primarily affects leaves, but sometimes attacks petioles and stems. On infected leaflets first appear small black spots. As the spots increase, whole leaflet is blackened. Heavy infections kill leaflets and cause severe …
La Certicilliose De La Luzerne En France Mise Au Point Apres 15 Annees D’Observations,
2025
INRA
La Certicilliose De La Luzerne En France Mise Au Point Apres 15 Annees D’Observations, J Gondran
IGC Proceedings (1977-2023)
La verticilliose de la luzerne (Verticillium albo-atrum R.B.) fut determinee pour la premiere fois en France il y a une trentaine d'annees. Depuis, nous avons etudie la repartition geographique de la maladie (Gondran, 1976) et la biologie du parasite· (Gondran, 1977). Nous avons mis au point un test de selection permettant de creer des varietes resistantes (Gondran in Massenot et al., 1978). Nous avons commence une etude sur la variabilite du pouvoir pathogene du champignon (Gondran, 1985). Nous nous proposons de faire le point sur !es etudes suivantes : degats de la maladie, variabilite du pouvoir pathogene du …
Observations Sur La Dissemination D’Epichloe Typhina, L’Agent De La Quenouille Des Graminees Et Reflexions Sur Les Diverses Especes D’Acremonium,
2025
lnstitut National Agronomique Paris-Grignon
Observations Sur La Dissemination D’Epichloe Typhina, L’Agent De La Quenouille Des Graminees Et Reflexions Sur Les Diverses Especes D’Acremonium, G Raynal
IGC Proceedings (1977-2023)
La quenouille des graminees est due a l'Ascomycete Epichloe typhina (Pers. ex Fr.) Tulasne. Des l'epiaison, Jes inflorescences malades sont emprisonnees clans un manchon blanc (stade asexue Sphacelia typhina = Acremonium typhinum), qui prend progressivement une couleur orangee, pour donner le sympt6me typique de quenouille. Le stroma des quenouilles renferme Jes loges peritheciales caracterisant le stade sexue Epichloe et produisant Jes ascospores responsables des contaminations. De nombreuses graminees sont attaquees, dont le dactyle ( Dactylis glomerata L.), qui peut subir de serieux dommages en France clans Jes regions de production de semence. En effet, Jes fleurs ne peuvent pas, …
Mycoflora Response To Burning On Sand Prairie,
2025
Illinois State University
Mycoflora Response To Burning On Sand Prairie, S S. Dhillon, C Anderson
IGC Proceedings (1977-2023)
The rhizoplane and root interior support different populations of microorganisms. A large number of these organisms are microfungi. Studies have shown that fire induced changes are favourable for some groups of microorganisms following grasslands fires. However, most studies have dealt with the effect of burning on surface and subsurface soil organisms but none have examined rhizoplane fungi. This study was conducted to examine little bluestem (Schizachyrium scoparium), a native prairie grass species, biomass production and associated vesicular-arbuscular mycorrhizae (V AM) and rhizoplane mycoflora and their response to burning.
Recent Effects Of Acremonium Coenophialum On The Performance Of Beef Cattle Grazing Festuca Arundinacea,
2025
University of Tennessee, Knoxville
Recent Effects Of Acremonium Coenophialum On The Performance Of Beef Cattle Grazing Festuca Arundinacea, H A. Fribourg, J B. Mclaren, A B. Chestnut, J C. Waller
IGC Proceedings (1977-2023)
Infection of tall fescue (F. arundinacea Schreb.) plants by the endophytic fungus A. coenophialum Morgan-Jones & Garns is associated with substantial economic reduction in grazing animal performance (Bacon and Siegel, 1988 ; Bush and Burrus, 1988 ; Stuedemann and Hoveland, 1988). This problem is serious in the transition zone of the eastern U.S.A., affecting over 12 million ha of pasture land.
Mutualistic Symbiosis Of Tall Fescue And Fungal Endophyte,
2025
University of Georgia
Mutualistic Symbiosis Of Tall Fescue And Fungal Endophyte, C S. Hoveland, C W. Bacon, N S. Hill
IGC Proceedings (1977-2023)
The greatly improved performance of livestock consuming low-endophyte tall fescue (Festuca arundinacea) forage has stimulated production of endophyte-free seed and replanting Acremonium coenophialum infected pastures (Stuedemann and Hoveland, 1988). Since endophytic fungi co-evolved with their host and are non-pathogenic, the endophyte-plant relationship is likely a mutualistic symbiosis (Bacon and Siegel, 1988). An important question arises as to whether tall fescue free of the endophyte will have the same productivity and persistence as infected grass in stressful environments. If the fungus benefits from the association by receiving nutrients, protection, reproduction, and dissemination, then the plant may be aided by …
Effect Of Differing Levels Of Acremonium Coenophialum Infection Of Tall Fescue (Festuca Arundinacea) On Bovine Serum Prolactin,
2025
University of Tennessee, Knoxville
Effect Of Differing Levels Of Acremonium Coenophialum Infection Of Tall Fescue (Festuca Arundinacea) On Bovine Serum Prolactin, A B. Chestnut, B H. Erickson, P P. Mckenzie, H A. Fribourg, J B. Mclaren, J C. Waller
IGC Proceedings (1977-2023)
Depressed concentrations of serum prolactin (PRL) have been observed in cattle grazing tall fescue (F. arundinacea Schreb.) infected with the endophytic fungus A. coenophialum Morgan-Jones and Garns (Thompson et al, 1987). Lower PRL concentrations may be partially responsible for poor performance of cattle consuming endophyte infected (E+ ) vs .. noninfected (E-) fescue since PRL is involved in mammary gland development, thermoregulation, and immune response. To determine the relationship between PRL concentration in cattle and percent E + plants in pastures they graze, studies were conducted at two locations in Tennessee.
Reaction Of Macroptilium Atropurpureum (Dc) Urb. Accessions To Angular Leaf Spot Caused By Isariopsis Griseola Sacc.,
2025
University of Florida
Reaction Of Macroptilium Atropurpureum (Dc) Urb. Accessions To Angular Leaf Spot Caused By Isariopsis Griseola Sacc., R M. Sonoda, A E. Kretschmer Jr
IGC Proceedings (1977-2023)
Macroptilium atropurpureum (D.C.) Urb. is a viny tropical legume, native to central America and tropical South America (Tothill 1966), with potential for pasture use in south Florida and other parts of the tropics and subtropics (Kretschmer, 1972). Isariopsis griseola Sacc. causes leaf spotting and defoliation of M. atropurpureum cultivar 'Siratro' in Florida (Lenne and Sonoda, 1985), in early spring and late fall, when forage availability is minimal. The disease is also present in native populations of M. atropurpureum in South and Central America (Lenne and Sonoda, 1985). I. griseola is generally considered to cause only minor damage (Lenne and …
Importance Of Rhizoctonia Foliar Blight Of The Promising Tropical Pasture Legume Genus Centrosema,
2025
CIAT
Importance Of Rhizoctonia Foliar Blight Of The Promising Tropical Pasture Legume Genus Centrosema, J M. Lenne, G Olaya, J W. Miles
IGC Proceedings (1977-2023)
Centrosema is a well-known American legume genus adapted to a wide range of tropical and subtropical environments. Several species have considerable potential as pasture legumes (Clements et al., 1983). Of 38 genera of fungal pathogens recorded on Centrosema, Rhizoctonia species, the causal agents of foliar blight, are regarded as the most damaging (Lenne et al., 1988).
Problems Associated With Evaluation Of Disease Of Perennial Pasture Plants - Some Recommendations,
2025
CIAT
Problems Associated With Evaluation Of Disease Of Perennial Pasture Plants - Some Recommendations, Jillian M. Lenne
IGC Proceedings (1977-2023)
Most of the existing pasture disease evaluation methodology has been developed for temperate grass and legume monocultures. Many techniques have been derived from annual crops with little modification and limited research has been done on perennial grass-legume pastures. Perennial pastures are heterogenous communities of various species of many ages supporting continuous pathogen associations. Because of temporal and spatial variation, diseases are difficult to evaluate and techniques are largely inadequate.
Fungal Diseases Limiting Productivity Of Annual Pasture Legumes In Western Australia,
2025
Baron Hay Court
Fungal Diseases Limiting Productivity Of Annual Pasture Legumes In Western Australia, M Barbetti
IGC Proceedings (1977-2023)
Subterranean clover (Trifolium subterraneum L.) and medic (Medicago species) form the basis of most annual pastures in Western Australia with approximately 6.5 and 1 million hectares sown respectively. Fungal pathogens cause a wide range of sporadic epidemics and insidious decline problems and have had a significant impact on the productivity of annual legume pastures during the past two decades (Johnstone and Barbetti, 1987). This paper outlines the fungal diseases involved in limiting production of annual pasture legumes in Western Australia and discusses control strategy options for the most important diseases.
Variation In Hypericum Perforatum L. In Australia,
2025
NSW Agriculture
Variation In Hypericum Perforatum L. In Australia, M H. Campbell, C E. May, I A. Southwell, J D. Tomlinson
IGC Proceedings (1977-2023)
In Australia Hypericum perforatum (St. John's wort) is a major weed of pastures because it replaces useful vegetation, causes photosensitisation in grazing animals, depresses their central nervous system and renders them hypersensitive to temperature change and handling (Campbell and Delfosse, 1984). H. perforatum infested 188,000 ha in New South Wales (N.S.W.) in 1976, (Campbell, 1977) and 173,000 ha in Victoria in 1983 (Shepherd, 1983). Specimens of H. perforatum collected in 1929 in N.S.W., Victoria and South Australia were classed as the narrow leaved var. angustifolium De Candolle (Calvert, 1930, 1932) at the Royal Botanic Gardens, Kew (B. Mathew, pers. …
Modalites D’Etude Des Nouvelles Varietes De Plantes Fourrageres Perennes En Vue De L’Inscription Au Catalogue Francias,
2025
INRA/GEVES
Modalites D’Etude Des Nouvelles Varietes De Plantes Fourrageres Perennes En Vue De L’Inscription Au Catalogue Francias, R Allerit, X Ballot, Francoise Blouet
IGC Proceedings (1977-2023)
L'ouverture de catalogues pour les especes fourrageres perennes remonte deja en France a plusieurs decennies, a la suite de la creation du Comite Technique Permanent de la Selection (C.T.P.S.); le premier fut celui de la luzerne en 1950, et le dernier en date est celui des bromes (catharticus et sitchensis) ouvert en 1982. Dans tous les cas, l'ouverture d'une liste offi.cielle se justifiait par des travaux de selection suffi.samment avances dans l'espece consideree et a toujours repondu au souci d'ameliorer et de diversifier la production fourragere. Jusqu'a l'ouverture du catalogue commun de la C.E.E. en 1970, les epreuves …
