Plant Pathology Commons^™

Rangeland Improvement On Granitic Soils In Uruguay, D F. Risso, D A. Moron

IGC Proceedings (1977-2023)

Granitic soils comprise more than 15% of productive land of the country, Soils are variable, all being deficient in nitrogen and phosphorus, having a moderately low pH, more than 40% being shallow with low levels of organic matter. Livestock production is predominantly developed on range with moderate yield and ample variations (avg. DM/ha/year=3.l t; c.v.=27.6%; winter yield=l2%), Research conducted to improve this situation, evaluated: 1) range P fertilisation during 5 years, which resulted in a small (but significant) yield increase and improved P concentration of forage. 2) P fertilisation and interseeding of legumes through different methods. Largest differences were due …

Use Of Dryland Forage Plants For Improving Semi-Arid And Hawkweed-Affected Land In New Zealand, B J. Wills, J S. Sheppard, J.S C. Begg

IGC Proceedings (1977-2023)

mi-arid climatic conditions affect large areas of New Zealand's South Island east coast and inland basins. A significant area - some 6 million ha - is affected by, or is at risk from, invasion by hawkweeds, mainly Hieracium pilose/la. This plant, along with rabbits, is severely affecting the viability of extensive pastoral grassland farming in New Zealand. Soil erosion, in particular associated with frost heave and wind, is notable in areas associated with both a semi-arid climate and high densities of hawkweeds. The use of dryland pasture plants selected for drought tolerance, frost tolerance and ability to grow under low …

Small-Grain Forage For Winter Pastures, D J. Undersander, D P. Hutchenson

IGC Proceedings (1977-2023)

The paper summarises 2 studies comparing wheal (Triticum aestivum), barley (Horderim vulgare), rye (Triticale secale), and triticale (x Triticoseca/e) for fornge production and animal performance. Wheat, rye and triticale were planted in 10, 20 and 30 cm row spacings and grown over 2 winters in South Carolina. Porage yield from early­October plantings ranged from 2961 to 5000 kg/ha in 1986-87 and from l012 to 3400 kg/ha in 1987-88. Porage yield was highest from rye, most of the forage growth occurring in autumn. Wheat produced forage growth most uniformly throughout autumn and spring. In the …

Effects Of Lime And Fertilizer On The Establishment Of White Clover In The Falkland Islands, J A. Kerr, Rosie Poultney

IGC Proceedings (1977-2023)

White clover (Trifolium repens L.)-based pastures could improve low pasture and animal production in the Falkland Islands. However, establishment is difficult and expensive. Effects of lime and fertilisers containing nitrogen (N), phosphorus (P) and potassium (K) on white clover dry matter yield and root nodulation were experimentally assessed between 1986-88. Lime at 1 t/ha and 30 kg/ha P as triple superphosphate, separately improved clover yield. Nodulation was improved only by lime. Neither N nor K fertilisers affected on white clover establishment yields,

Complementarity Between Summer-Active Grasses And Cool-Season Annual Legumes In Temperate-Zone Pastures, W H. Johnston

IGC Proceedings (1977-2023)

The effect of mowing and subterranean clover (Trifolium subterraneaum) on plant density; basal area and total dry matter yield of the C perennial grasses Eragrostis curvula complex, cv. Consol and 4 Accession 4660, and Cenchrus ciliaris cv. American, and the c; Pllalaris aquatica cv. Sirocco was studied at Cowra, NSW, Australia between spring 1982 and spring 1987. C. cilaris did not persist. The density and basal area of phalaris was not affected by subterranean clover but declined with mowing, Clover reduced the density, basal area and summer dry matter ·yield of E. curvula while mowing was', advantageous. E. curvula …

Winter Grazing Rough Fescue Grasslands With And Without Preconditioning On Annual Pasture, W D. Willms, L M. Rode, B S. Freeze

IGC Proceedings (1977-2023)

Winter grazing of the fescue prairie is desirable to reduce the cost of feeding preserved forages and to conserving the native prairie. Rough fescue (Festuca campestris Rydb,), the dominant and most productive forage species in the foothills region, is highly sensitive to summer grazing but tolerates grazing while dormant. Since the forage quality declines after senescence, and the energy requirements increase in winter, this study was made to determine the feasibility of winter gmzing pregnant Hereford cows with and without preconditioning on annual pasture. The study, replicated over a 4-year period {n=4), used a 2x2 factorial design representing native …

Interaction Of Drill Type And Herbicide On Pasture Establishment In Semi-Arid Environments, W L. Lowther, R F. Horrell, P D. Johnstone, K D. Trainor

IGC Proceedings (1977-2023)

Results are presented from an overdrilling experiment comparing a conventional triple-disc drill with an' experimental single-pass strip­seeder drill designed to remove competiting vegetation mechanically; Herbicide application markedly increased herbage mass of sown species in the triple-disc treatments. ,However, herbage mass was. higher from the strip-seeder drill than the .triple-disc in both ihe' nbsence and presence of herbicide. The results indicate the potential of the strip-seeder drill technology for cost-effective establishment of pasture species in difficult environments.

Alfalfa Cultivar Selection From 30 Years Of Records In The State Of Illinois, Usa, Don W. Graffis

IGC Proceedings (1977-2023)

Data from alfalfa (Medicago sativa L.) cultivar trials in Illinois, USA from 1963 lo 1992 have been adapted to a computer software spreadsheet for storage and manipulation. The data recorded have been the percentage of check cultivar's yield. The average % of checks for a given cultivar is calculated after each year of recorded yield. The computer spreadsheet enables sorting of resultant yields. The sorting in descending order determines lhe top-performing cultivars. Criteria used lo determine cultivar suggestions for extension clienlele are: (a) a minimum of 3 harvest years in the region of cultivar suggestion, and (b) the cultivar …

Developing Eastern Gamagrass On A Conserved Forage, John A. Dickerson, Paul R. Salon

IGC Proceedings (1977-2023)

Bastern gamagrass (Tripsacum dactyloides L.) is highly regarded as a native forage resource in the prairie region of North America. Recent discovery of a gynomonoecious plant in Kansas has raised expectations that efficient seed production will be possible with the species. A possible use for eastern gamagrass is as a perennial haylage crop for dairy farms, replacing erosion-prone silage corn. Compared with corn silage, eastern gamagrass forage has higher crude protein, slightly lower energy, and higher neutral detergent fibre and acid detergent fibre. Breeding work is underway to develop hardy, high volume forage-producing strains with good seed production capability. …

Rangelands In Dry Mountain Areas, T Boyadgiev

IGC Proceedings (1977-2023)

The extent and characteristics of temperate and mountainous climatic zones, steeply dissected and mountainous areas, permanent meadows and pasture lands, and the trend of land use evolution and aspects of land degradation are presented and discussed. The rangelands improvement strategy in Bulgaria is based on mineral fertilisation of mountainous grasslands leading to an increase in production of dry material, protein, phosphorus and cereals, This reduces sheet erosion. Overgrazing and prolonged dry periods, causing a decrease in the number of species, are also discussed, Measures to improve grassland practices are proposed.

Improvement Strategies In Winter Cold Temperate Rangeland Ecosystems With Particular Reference To Extensive Grazing Lands Of Iran, A Koocheki

IGC Proceedings (1977-2023)

Traditional land use systems in Iran have been divided between crop production and livestock grazing. Grazing land management in most parts is based on pastoral nomadism which operates between plains as winter grazing lands and mountains as summer grazing lands. Mountainous areas are an important source of food and feed production for nomads and their herds. In Iran two main ranges of mountains, Elburz and Zagros, are the summer territory of nomadic pastoralists. At present 1.5% of total population of the country are nomads. They contribute as much as 27% of value added in the animal industry of the country. …

Winter Cold Temperate Rangelands: Improvement Strategies For Intensive Rangeland Ecosystems, B E. Allan, D Scott

IGC Proceedings (1977-2023)

Transfer of developed grassland technologies to rangelands is discussed in terms of environmental gradients and the options and constraints they impose. Winier feed limitation can be overcome through conserved feeds and various in situ systems involving special purpose pastures and feed banks. General animal nutrition can be improved through intensive development, low input systems, better control of range utilisation and, where appropriate, correction of mineral deficiencies. The emphasis in seeking quick and easy solutions to rangeland management problems is questioned, A more informed, environmentally sound and sustainable approach to rangeland fanning atlitudes and management is proposed. A stepwise process to …

Bodine: An Agent-Based Modeling Approach To Studying Localized Coexistence Across Environmental Heterogeneity, Alexandra Campbell

Annual Symposium on Biomathematics and Ecology Education and Research

No abstract provided.

Lupin Root Diseases - Diagnosis And Management, Department Of Primary Industries And Regional Development, Western Australia

Grains and other field crops factsheets

Root, hypocotyl and stem base diseases can be significant problems in lupin crops, reducing stand density, plant vigour and yield. Root disease is present in nearly all narrow leafed lupin (Lupinus angustifolius) paddocks but in the majority of paddocks has only a small impact on crop development. However, in paddocks where high levels of root rot occurs, plant establishment, seedling vigour and crop yield can be significantly affected.

When a root disease is present in a crop very little can be done to manage it in that cropping season. It is therefore vital that the cause is correctly identified to …

Effects Of Cultivars And Fungicides On Foliar Fungal Diseases And Fusarium Head Blight In Winter Wheat, Mahnoor Asif

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Foliar fungal diseases and Fusarium head blight (FHB) are among the major causes of significant yield losses in wheat production, particularly in Nebraska. Resistant cultivars and fungicide applications are common management strategies, but the overuse of fungicides has raised concerns about resistance in Fusarium graminearum populations in Nebraska. This study evaluated the effects of cultivar resistance, fungicide timing and their economic benefits. It also assessed the sensitivity of Nebraska isolates of F. graminearum and F. boothii to a triazole fungicide. In 2022 and 2024, 14 fungicide treatments and a control were arranged in a split-plot experimental design with …

Understanding Limitations In Photosynthesis And Cold Tolerance In Panicoid Grasses: Maize And Sorghum, Fangyi Li

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

Sorghum and maize, both key crops within the Poaceae family (commonly known as the grass family), are staple foods in various regions and play a vital role in global food systems and economic development. These crops thrive in similar climates, particularly in warm, arid, and semi-arid regions. As subjects of extensive agricultural research, both maize and sorghum are being studied to enhance stress resistance and improve yield. Due to their botanical similarities, advances in one crop often inform practices in the other. The goal of this dissertation is to deepen our understanding of the photosynthesis process and cold tolerance in …

Addressing Knowledge Gaps In Disease Epidemiology And Detection Of Fungicide Resistance In Cercospora Leaf Blight Of Soybean, Stephanie Karen Ramos

LSU Master's Theses

Cercospora leaf blight (CLB) has been the primary foliar disease impacting the soybean crop in the mid-South for over a decade. A poor understanding of disease epidemiology and the prevalence of fungicide resistance have added complexity to management efforts. Recent findings suggest that airborne conidia play a significant role in the outbreak of CLB. We investigated the relationship between weather variables and conidial release using multi-site, multi-year spore trapping data. The findings confirm that C. cf. flagellaris is the dominant CLB pathogen, contributing significantly more conidia than C. cf. sigesbeckiae and C. kikuchii in soybean fields across Arkansas, Mississippi, …

Evaluation Of Nematicides For Management Of Plant-Parasitic Nematodes In Sugarcane, Iris M. Aguilar

LSU Master's Theses

Plant-parasitic nematodes (PPN) are an understudied threat in sugarcane production. Previous survey work showed that Tylenchorhynchus (stunt nematode), Pratylenchus (lesion nematode), Mesocriconema (ring nematode), and Helicotylenchus (spiral nematode) are the primary PPN genera found in sugarcane fields in Louisiana. This study evaluated the impact of nematodes on sugarcane growth and the effect of nematicides on nematode population densities. Greenhouse studies were conducted using soil collected from multiple sugarcane fields with moderate PPN infestation levels to determine the nematode impact on sugarcane growth and nematicide efficacy. Field soil collected from each site was subjected to four treatments: an untreated and sterilized …

Identification And Characterization Of Resistance To Meloidogyne Enterolobii And M. Incognita In Sweetpotato Genotypes, David M. Galo Espinal

LSU Doctoral Dissertations

Root-knot nematodes (RKN), Meloidogyne spp., are significant agricultural pests that cause severe economic losses on a wide range of agricultural crops worldwide, including sweetpotato. The economic viability of the sweetpotato industry in the United States is threatened by Meloidogyne enterolobii, which reproduces on sweetpotato cultivars resistant to other RKN species. To address this issue, 69 sweetpotato genotypes were evaluated to identify sources of resistance to M. enterolobii (Me) and M. incognita (Mi). Results showed that twenty-six genotypes were highly resistant to Me and eleven were resistant to Mi, with three genotypes showing resistance to …

Effect Of Crop Age On Seed Yield Of Arachis Pintoi At Two Sites In Costa Rica, Pedro J. Argel, Alfredo Valerio

IGC Proceedings (1977-2023)

Arachis pintoi is a forage legume well adapted to the humid tropics of Costa Rica. Seed production studies were carried out at two contrasting localities within the country, Gulipiles (very humid tropics) and San Isidro (seasonal evergreen tropical forest). The accessions CIAT 18748, 18744 and 17434 cv. Amarillo of A. pinloi were vegetatively planted at both sites. Seed yields were measured at 8, 12, 16 and 20 months post- planting inGulipiles, and at·8, 16 and 20 months in San Isidro. Mean seed yields among accessions were similar in San Isidro but significantly different in Gulipiles; however, the contrary occurred in …

Efficient Nitrogen Fertilization In Grass Seed Crops With Regard To Soil Mineral Nitrogen Content And Analyzing Grass Tillers In Spring, W Schoberlein, H J. Wahl

IGC Proceedings (1977-2023)

When applying the Nmln method in grass seed crops analogously lo that in cereal crops we proceed from the experience that for a mean level of mineralisation, the sum total of soil-borne Nm1n available to plants at the beginning of the growth period and Nd Input in the form of fertiliser will provide sufficient N to the crop. The total quantity of mineral soil-borne N and fertiliser N is considered as the nominal value. The required N input can be derived from the difference between nominal value and mineral soil-borne N (Nd = nominal value• Nrnin>· For Dactylis glomerata …

Effects Of Aneuploidy On Seed Production In Autopolyploid Forage Crops, A Elgersma

IGC Proceedings (1977-2023)

Between the selection of a population and its commercial use, several generations of multiplication are necessary. The essential feature in variety maintenance is that no genetic changes occur during multiplication. In seed-propagated species, however, during each multiplication cycle natural selection takes place at ihe gamete, zygote, seed and plant level. In induced autopolyploids high frequencies of aneuploids can occur. Aneuploidy not only affects the seed yield level, but also the selection processes that occur during multiplication. It may cause genetic shift and affect variety stability. Species differ in their tolerance to aneuploids. It is not possible to eliminate aneuploidy by …

Effects Of Ratooning And Protection From Diseases And Birds On Seed Production In Guinea Grass, Okoro Oji, F N. Madubuike, F.O C. Ezedinma

IGC Proceedings (1977-2023)

Effects of ratooning and protection from diseases and birds on seed production in guinea grass (Pannicum maximum L.) were assessed in a study from October 1986 to April 1987. Treatments included ratooning and mancozeb application with or without protection from birds (netting). Highest yield occurred with combined netting and mancozeb application. Mancozeb sp,aying without netting gave lower seed yield than netting without fungicide spraying. Seed yield, which generally decreased with ratooning, was lowest among unnetted and unsprayed crops. Prom anthesis to seed maturation lasted, on average, 9 days, and seeds borne on the upper part of the panicle matured …

Potential For Improved Honey Bee Pollination Efficiency From Easy-To-Trip Lucerne, L R. Teuber, E E. Knapp

IGC Proceedings (1977-2023)

The principal pollinator of lucerne (Medicago sativa L.) in California, USA is the honey bee (Apis mellifera L.). However, honey bees are notoriously inefficient pollinators of lucerne because they learn to avoid tripping the floret. Easy-to-trip lucerne florets could reduce this problem. These studies were designed to determine the inheritance of ease of tripping and assess the effect of ease of tripping on the rate of outcrossing. Both additive and digenic variance for ease of tripping were significant, resulting in a heritability of 34.0:1:16.2%. Ease of tripping had no influence on outcrossing rate, which was estimated to average …

Effect Of Final Cutting For Fodder On Seed Yield And Seed Quality In Berseem, S L. Saini, R K. Chowdhury

IGC Proceedings (1977-2023)

The study was conducted to determine the appropriate time of final culling (closing) for fodder to optimise the seed yield and seed quality in berseem (Trifolium alexandrinum L.). Based on 2 years' experimentation, the maximum seed yield was obtained when the final cut for fodder was taken in mid•March and the crop was then closed for seed. Seed yield was reduced drastically when the final cut was delayed to late March•April. The seed quality parameters of standard germination, seed weight and vigour index were also reduced when the final cut for fodder was delayed to late March•early April. Based …

Effect Of Post-Harvest Management Practices On Seed Yields On Fine-Leaf Fescue, Gale A. Gingrich, William C. Young Iii, Thomas B. Silberstein

IGC Proceedings (1977-2023)

Public opposition and legislative actions have restricted the practice of open-field burning of grass seed fields in Western Oregon's Willamette Valley. Finding economically acceptable alternatives to straw residue removal has become a priority for valley grass seed growers. Trials using 4 residue management practices were established on 2 commercial fine fescue (Festuca rubra) seed fields. Seed yields varied significantly between residue management practices. Seed yields from thermal-treated plots were equal or significantly greater than yields from the non-thermal treatments. Fertile tiller number was also greater with thermal treatments. Most fine fescue fields produce 4-6 seed crops before replanting, …

Floret Site Utilization Of White Clover, A H. Marshall, D H. Hides

IGC Proceedings (1977-2023)

Plants of white clover (Trifolium repensL.) cv. Olwen were grown in an open glasshouse at 20°C and ovule growth and development measured. Differences in the rate of growth of ovules within ovaries were observed as early as 2 days after pollination. Ovules reached a maximum size after 8 days, with the smallest only half the size of the largest. After 8 days the smallest ovules became flaccid and shrivelled. Ovule position within the ovary had no effect on the frequency of seed set. Inflorescence position and floret position on the inflorescence had a significant effect on the number …

Influence Of Harvest Date On The Yield And Quality Of Seed Of Phalaris, K Reddy, W R. Scott, R J. Lucas

IGC Proceedings (1977-2023)

Grasslands Maru phalaris (Phalaris aquatica L,) was harvested every third day commencing 12 days after mid-anthesis (DAA) to define the optimum time of harvest for seed yield and quality. Harvesting earlier than 21-24 DAA reduced 1000-seed weight and viability. Delaying harvest until 24 days reduced seed yield due to shattering but had no detrimental effect on seed weight and viability. Heavy seed losses occurred 24 DAA when seed moisture fell below 40%. The results of this experiment suggest that Maru phalaris should be harvested 21-24 DAA when the seed moisture is in the range of 40-42% to reduce the …

Annual Bluegrass And Rat's Tail Fescue Control In Perennial Ryegrass, M E. Mellbye, William C. Young Iii, George W. Mueller-Warrant

IGC Proceedings (1977-2023)

Annual bh1egrass (Poa annua L.) and rat's-tail fescue (Vulpia myruros (L.) C.C. Omel.) are common weed contaminants in seed from perennial ryegrass fields Lolium perenne L. grown in Oregon. A trial was conducted to evaluate post-harvest residue removal methods and herbicides to reduce the level of these impurities. The best weed control was obtained from herbicides following crew-cut management, a comparatively thorough non-thermal nppronch to residue removal. Control was good with sequential herbicide treatments, especially when an effective pre-emergence herbicide such as pendimethalin was used, although no treatment completely eliminated annual bluegrass and rat's-tail fescue from threshed seed samples …

Flowering And Seed Production Of Centrosema Spp. In Relation To Day Length And Temperature, R.J M. Gonzalez, R J. Clements, L R. Humphreys

IGC Proceedings (1977-2023)

The effcc1s of variation in daylength and temperature on the flowering processes leading to seed production were studied in genotypes of 5 Centrosema spp. Short days (11 h) enhanced flowering in accessions of C. virginatum from low latitude but flowering of lines from high latitude was more prolific in 16-h days. A quantitative long-short day response was evident in 2 intermediate latitude accessions. The critical photoperiod for flowering·varied: C. virginianum cross 31 flowered in 13.5 h or less, C. pubescens, C. pascuorum and C. macrocarpum in 12 h or less, and C. schiediam Oowcred only in a 10.5 …