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Plant Pathology

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Articles 9571 - 9600 of 9752

Full-Text Articles in Agronomy and Crop Sciences

Northern Australia Quarantine Strategy. Weeds Target List, B. M. Waterhouse, A A. Mitchell Jan 1998

Northern Australia Quarantine Strategy. Weeds Target List, B. M. Waterhouse, A A. Mitchell

Biosecurity published reports

Second edition.

The Northern Australia Quarantine Strategy (NAQS) was established in 1989 as an outcome of a major evaluation of quarantine in Australia (AGPS 1987, 1988). NAQS activities include surveying for weeds,insect pests and diseases of plants; and pests and diseases of animals in northern Australia, Papua New Guinea and Indonesia. The primary goal is to provide early detection and warning of new quarantine threats or incursions.

A targetted approach was adopted for all pests, diseases and weeds. For each category of pest, experts in the discipline compiled lists of organisms not known from Australia but known to occur in …


Seasonal Occurrence Of Rice Yellow Mottle Virus In Lowland Rice In Côte D’Ivoire, E. A. Heinrichs, A. A. Sy, S. K. Akator, I. Oyediran Jan 1997

Seasonal Occurrence Of Rice Yellow Mottle Virus In Lowland Rice In Côte D’Ivoire, E. A. Heinrichs, A. A. Sy, S. K. Akator, I. Oyediran

Department of Entomology: Faculty Publications

Monthly plantings of the rice variety Bouaké 189 were made under lowland irrigated conditions, to obtain information on the phenological and seasonal occurrence of pests and diseases on the West African Rice Development Association (WARDA) research farm near Bouaké, Côte d’Ivoire. Regular sampling of insect pests and observations on rice yellow mottle virus (RYMV) disease infection throughout the year provided information on the occurrence of RYMV and potential insect vectors. RYMV incidence and grain yields varied depending on planting date, and for a given planting date, varied from one year to another. There was no evidence that RYMV incidence increases …


Effect Of Media Constituents On In Vitro Culturing Of Cowpea (Vigna Unguiculata) Shoot Tip And Leaf Disk Explants, Mohanjeet S. Brar, Edwin J. Anderson, Teddy E. Morelock, Ronald W. Mcnew Jan 1997

Effect Of Media Constituents On In Vitro Culturing Of Cowpea (Vigna Unguiculata) Shoot Tip And Leaf Disk Explants, Mohanjeet S. Brar, Edwin J. Anderson, Teddy E. Morelock, Ronald W. Mcnew

Journal of the Arkansas Academy of Science

Cowpea is an important legume food crop that is commonly grown in Arkansas and numerous other southern states. The application of biotechnological approaches for the improvement of U.S. cowpea genotypes is currently not possible due to the lack of a regeneration and transformation system. Therefore, the first priority of our research efforts is the development of a plant regeneration system that will facilitate plant transformation studies. In an effort to optimize the media requirements for tissue culturing cowpea, we evaluated the in vitro response of shoot tip and leaf disk explants to various levels of Murashige and Skoog (MS) macro …


Coming To Grips With Eradu-Patch Of Lupins, Bill Macleod, Mark Sweetingham Jan 1995

Coming To Grips With Eradu-Patch Of Lupins, Bill Macleod, Mark Sweetingham

Journal of the Department of Agriculture, Western Australia, Series 4

Investigations by Bill MacLoud and Mark Sweetingham have confirmed that Eradu-patch of lupins is caused by apreviously undescribed fungal pathogen,\.

They have developed strategies to minimise the spread of patches but choices are limited for control in lupin crops


Cucumber Mosiac Virus In Lupins, Annette Bwye, Roger Jones, Wayne Proudlove Jan 1995

Cucumber Mosiac Virus In Lupins, Annette Bwye, Roger Jones, Wayne Proudlove

Journal of the Department of Agriculture, Western Australia, Series 4

Cucumber mosaic virus is a threat to lupin crops from Geraldton to Esperance, particularly to those growing in areas receiving more than 400 mm average annual rainfall. The disease markedly decreases grain yield in narrow-leafed and yellow lupins but doesnot infect albus or sandplain lupins. Worldwide , after bean yellow mosaic virus, cucumber mosaic virus is the second most important virus affecting lupins. Annette Bwye, Roger Jones and Wayne Proudlove outline the symptoms, spread and management of this serious disease.


Pulses : Profitable New Crops For The Wheatbelt, Kadambot Siddique, Stephen Loss, Ian Pritchard Jan 1995

Pulses : Profitable New Crops For The Wheatbelt, Kadambot Siddique, Stephen Loss, Ian Pritchard

Journal of the Department of Agriculture, Western Australia, Series 4

Narrow-leafed lupins have beeb produced on sandy acid soils throughout the wheatbelt for more than two decades. However, the wheatbelt contains large areas ofsoilsnot suited to narrow-leafed lupins. For several years reasearchers have been examining alternatives to narrow-leafed lupins for these soils.

Kadambot Siddique, Stephen Loss and Ian Prichard look at production of these new grain legumes, known as pulses.


Bulletin 4294 - Virus Diseases Of Lupins, Roger Jones Dec 1994

Bulletin 4294 - Virus Diseases Of Lupins, Roger Jones

Bulletins 4000 -

Two virus diseases pose a serious threat to lupins. These are caused by cucumber mosaic virus (CMV), which induces diseases in narrow-leafed and yellow lupins, and bean yellow mosaic virus (BYMV), which infects all types of cultivated lupins. The effects of the viruses on lupin plants range from subtle colour changes and leaf distortion to leaf shedding, stunting and death. Seed production is decreased or prevented. There is no cure, but lupin crops can be managed to minimise both virus spread and its persistence from year to year.

CMV and BYMV occur within all tissues in the plant, but do …


Barley Yellow Dwarf Virus In Cereals, Simon Mckirdy, Roger Jones Jan 1993

Barley Yellow Dwarf Virus In Cereals, Simon Mckirdy, Roger Jones

Journal of the Department of Agriculture, Western Australia, Series 4

Worldwide, barley yellow dwarf virus (BYDV) is the most widespread and damaging virus disease of cereals. It infects wheat, barley, oats and grasses and is transmitted by several aphid species. The virus is not seed-borne and to persist from one growing season to the next it must survive in over-summering grasses.

Barley yellow dwarf virus decreases grain yield and also causes shrivelled grain. Yield loss is greatest from infection early in the growing season.


Role Of Endophytes In Tall Fescue, E. L. Piper, C. P. West Jan 1993

Role Of Endophytes In Tall Fescue, E. L. Piper, C. P. West

Journal of the Arkansas Academy of Science

Tall fescue (Festuca arundinacea Schreb.) is the most commonly grown cool season grass used for pastures in Arkansas. Most tall fescue contains a fungal endophyte (Acremonium coenophialum Morgan-Jones & Gams), which causes fescue toxicosis in livestock and costs cattle producers millions of dollars annually in lost production. Endophyte presence is known to reduce wild mammal populations in areas where tall fescue is prevalent. The endophyte spends its entire life cycle within the plant and is transmitted through the seed. The association is mutualistic with the plant providing nutrients for the endophyte and the endophyte conferring drought, insect, and nematode resistance …


Pesticide Use On Sweet Corn Grown In Connecticut: 1990, James L. Turner Ii, Candace L. Bartholomew Sep 1992

Pesticide Use On Sweet Corn Grown In Connecticut: 1990, James L. Turner Ii, Candace L. Bartholomew

Storrs Agricultural Experiment Station

No abstract provided.


Stubble Retention And Leaf Disease In Lupin And Cereal Crops, Mark Sweetingham, Robert Loughman, Ron Jarvis Jan 1992

Stubble Retention And Leaf Disease In Lupin And Cereal Crops, Mark Sweetingham, Robert Loughman, Ron Jarvis

Journal of the Department of Agriculture, Western Australia, Series 4

Retention of cereal stubbles can reduce leaf disease in lupins but increase leaf disease in cereals. The extent of cereal disease carry-over in stubbles depends on the locality and whether multiple cropping or crop rotation is practised


Sterol Composition Of The Corn Root Lesion Nematode, Pratylenchus Agilis, And Corn Root Cultures, David J. Chitwood, William R. Lusby Jan 1991

Sterol Composition Of The Corn Root Lesion Nematode, Pratylenchus Agilis, And Corn Root Cultures, David J. Chitwood, William R. Lusby

Harold W. Manter Laboratory of Parasitology: Faculty Publications

Sterols from mixed stages of the com root lesion nematode, Pratylenchus agilis, and uninfected corn root cultures were analyzed by gas chromatography-mass spectrometry. Twenty-eight sterols were identified in P. agilis, including nine not previously detected in nematodes. The major sterols were 24-ethylcholest-22-enol, 24-ethylcholesta-5,22-dienol, 24-methy1cholestanol, 24-ethylcholestanol, isofucostanol, and 24-ethylcholesterol. The principal corn root sterols were 24-ethylcholesta-5,22-dienol, 24-methylcholesterol, 24-ethylcholesterol, isofucosterol, and cycloartenol. Therefore, the major metabolic transformation of sterols by P. agilis was saturation of the sterol nucleus. In addition, very small amounts of 4α-methylsterols were biosynthesized by P. agilis. The 4-methylation pathway is unique to nematodes and was …


Origin And Evolution Of Defective Interfering Rnas Of Tomato Bushy Stunt Virus, David A. Knorr, Thomas Jack Morris Jan 1991

Origin And Evolution Of Defective Interfering Rnas Of Tomato Bushy Stunt Virus, David A. Knorr, Thomas Jack Morris

School of Biological Sciences: Faculty Publications

Viruses with defective genomes have been identified in association with virtually every major family of viruses and have been widely utilized as tools for investigating virus functions in animal cell culture systems (Perrault, 1981). It is generally thought that defective interfering viruses (DIs) arise through deletion, rearrangement, or recombination of a competent viral genome. DIs tack the ability for independent existence relying on their parental helper viruses to supply factors required for replication, maturation, and/or encapsidation (Huang and Baltimore, 1977). The interference attributed to DIs is thought to result from competition with the helper virus for factors required in trans …


Pesticide Use On Crops In Nebraska - 1987, Maurice Baker, Nancy Peterson, Shripat T. Kamble Aug 1990

Pesticide Use On Crops In Nebraska - 1987, Maurice Baker, Nancy Peterson, Shripat T. Kamble

Nebraska Agricultural Experiment Station: Historical Research Bulletins

This is the third and most comprehensive study of pesticide use on crops in Nebraska. The first was completed in 1978 and the second one in 1982. The first study indicated that approximately 25 million pounds (11.34 million kg) of active ingredients were used on the major crops in Nebraska. This increased to approximately 30.2 million pounds (13.7 million kg) in 1982. The USDA requires accurate information to meet their responsibilities. Thus, this survey was undertaken to determine: 1) the use of pesticides on crops, pasture and rangeland and 2) to identify pest management practices.


Coping With Brown Spot And Root Rots Of Lupins, Mark Sweetingham Jan 1990

Coping With Brown Spot And Root Rots Of Lupins, Mark Sweetingham

Journal of the Department of Agriculture, Western Australia, Series 4

There is increasing concern that brown spot and root diseases may limit the long term viability of lupin cultivation in close rotations in the agricultural areas of Western Australia. Research has found several useful strategies to reduce the impact of brown spot and Pleiochaeta root rot so that losses can be kept to a minimum. Rhizoctonia has proved more difficult to combat. Although less widespread than Pleiochaeta, it has caused severe losses and appears to be increasing in incidence, particularly in the northern wheatbelt. Research has vastly expanded our knowledge of the strains of Rhizoctonia present in our soils and …


Managing Diseases Of Alfalfa, Paul C. Vincelli, Garry D. Lacefield, Jimmy C. Henning Jan 1990

Managing Diseases Of Alfalfa, Paul C. Vincelli, Garry D. Lacefield, Jimmy C. Henning

Agriculture and Natural Resources Publications

Alfalfa can be a vigorous and productive forage crop for Kentucky farmers. Like all farm crops, however, alfalfa is subject to infectious diseases that can limit forage production. Managing these diseases is an important part of economical alfalfa production.

Alfalfa diseases can cause reduced forage yield, reduced forage quality, and decreased stand persistence. Sometimes, the effects of infectious diseases can be dramatic, such as sudden stand loss in a fall-seeded crop caused by Sclerotinia crown and stem rot. Often, the effects of diseases on alfalfa are more subtle but no less important. For example, alfalfa plants with Phytophthora root rot …


Studies On The Giant Mealie Witchweed, Striga Forbesii Benth., In Zimbabwe, David Allen Knepper Oct 1989

Studies On The Giant Mealie Witchweed, Striga Forbesii Benth., In Zimbabwe, David Allen Knepper

Biological Sciences Theses & Dissertations

Of the seven species of Striga found in Zimbabwe, S. forbesii Benth. is currently the most destructive in terms of crop damage. Owing to its limited occurrence worldwide as a pest of crops, relatively little work has been done on this species.

Striga forbesii has been found to be a consistent problem on both maize and sorghum in the Hunter's Road District of KweKwe, Zimbabwe. Results of a pot study and field observations, indicate S. forbesii can successfully parasitize Urochloa panicoides Beauv., Sorghum arundinaceum (Desv.) Stapf, and Rottboellia cochinchinensis (L.) L.f., all of which are widespread weeds of arable land. …


Bulletin 4133 - Fungal Diseases Of Pasture Legumes In Western Australia, M. J. Barbetti Sep 1989

Bulletin 4133 - Fungal Diseases Of Pasture Legumes In Western Australia, M. J. Barbetti

Bulletins 4000 -

Subterranean clover (Trifolium subterraneum L.) is the most important annual pasture legume in Western Australia, forming the basis of some 6.5 million ha of annual pastures. The success of subterranean clover may be attributed to its ability to increase soil fertility as a consequence of nitrogen fixed, to withstand heavy grazing, to control soil erosion and, with some cultivars, to tolerate waterlogging. Fungal diseases have been a major limitation to the productivity of subterranean clover, affecting both the amount of plant matter and the quantity of seed produced.

Annual medic (Medicago spp., in particular M. polymorpha L.) is also an …


Breeding Phomopsis-Resistant Lupins, John Sylvester Gladstones Jan 1989

Breeding Phomopsis-Resistant Lupins, John Sylvester Gladstones

Journal of the Department of Agriculture, Western Australia, Series 4

The release of Gungurru and Yorrel lupins marks the coming of age of the narrow-leafed lupin as a crop plantt. These are the first cultivars of the species th have substantial resistance to Phomopsis stem blight, which will make the stubbles much safer for grazing stock.

This article describes the new lupins, their background, and how they were bred. It also acknowledges the contributions of colleagues who helped in important ways.


Erosion Potential Of Phomopsis-Resistant Lupins, D J. Carter, Paul Findlater Jan 1989

Erosion Potential Of Phomopsis-Resistant Lupins, D J. Carter, Paul Findlater

Journal of the Department of Agriculture, Western Australia, Series 4

During lupin harvesting, up to 20 per cent of the grain remains on the ground. This non-harvested or pilt grain is a valuable feed for sheep during early summer because the pods, leaf and stem generally provide little nutrient in the stubnbles. In addition, the more efficient the weed control, the less valuable are the stubbles.

The disease lupinosis caused by Phomopsis leptostromiformis restricts the amount of grazing from the lupin stubbles, and hence the risk of wind-erosion of stubble paddocks.

However, the introduction of lupin varieties moderately resistant to Phomopsis and with reduced potential to cause lupinosis means that …


Breeding Field Peas : Screening Pea Lines, G H. Walton Jan 1989

Breeding Field Peas : Screening Pea Lines, G H. Walton

Journal of the Department of Agriculture, Western Australia, Series 4

The early use of field peas in Western Australia was as a green manure crop or to feed stock be grazing the mature crop. Varieties which produced a large bulk of green material were sown. There was no control over insects or diseases.

In 1985, the Feseral Government recognised that to realize the potential of grain legumes grown throughout Australia, more research was needed.

One of the Grain Legume Research Council's (GLRC) priorities is species evaluation and variety improvement.

Since 1983, the Western Australian Department of Agriculture has screened advanced crossbred lines from the South Australian breeding programme for its …


Selection And Development Of Early Maturing Varieties Of Murex Medic., D. J. Gillespie Jan 1988

Selection And Development Of Early Maturing Varieties Of Murex Medic., D. J. Gillespie

Experimental Summaries - Plant Research

Trial 88A25, 88MO44, 88NA83, 88AL15

Location: Avondale, New Norcia, Darkan, Cranbrook, Arthur River, Kellerberrin North Quairdading, Gabalong, Merredin, Badgebup and Pingrup.

Over 300 recent overseas introductions of murex medic were evaluated in rows at South Perth in 1988. Of these 15 selections were identified with acceptable spinniness that flower in 100 days or less. Four years ago there was only one selection flowering in under 110 days and that was spiny!

These selections will be evaluated in small plot trials in several country sites in 1989.

This programme aims to identify superior varieties to Zodiac which was released in 1988.


Effects Of Planting Date On Development Of Net Blotch Epidemics In Winter Barley In Pennsylvania, Leslie M. Delserone, H. Cole Jr. May 1987

Effects Of Planting Date On Development Of Net Blotch Epidemics In Winter Barley In Pennsylvania, Leslie M. Delserone, H. Cole Jr.

University of Nebraska-Lincoln Libraries: Faculty Publications

The influence of planting date on fall and spring net blotch epidemics (caused by Pyrenophora teres) was evaluated with the winter barley cultivar Pennrad. Experiments were conducted in Centre County, Pennsylvania, in 1982 and 1983 and in Lancaster County, Pennsylvania, in 1983. The three planting dates evaluated corresponded to the recommended date as well as dates I wk earlier and later than recommended for each specific location. Planting date had a significant influence on fall net blotch epidemics, with the greatest and least disease severities observed in the earliest and latest plantings, respectively. When spring environmental conditions were warm …


Root Disease Of Cereals, G C. Macnish, Chang Sha Fang, Karen Mcroberts Jan 1987

Root Disease Of Cereals, G C. Macnish, Chang Sha Fang, Karen Mcroberts

Experimental Summaries - Plant Research

Effects of nitrogen source on take-all, 82N34, 77E4. Take-all, cultivar, fertilizer, fungicide interactions, 87MT47, 87MT48, 87MT49. Take –all decline, 86MT7. Rhizoctonia root rot. Rhizoctonia patch and soil compaction, 87E28. Rhizoctonia patch and short chemical fallow, 87E3, 87E38. Rhizoctonia strains and paddock history, 87E31. Rhizoctonia root rot - host effects on strains, 87BA4, 86E30. Fusarium crown rot. Fusarium crown rot and cultivars, 87ME2, 87ME4, 87ME3 ( abandoned ).


Research Into Lupin Root Diseases, M W. Sweetingham Jan 1986

Research Into Lupin Root Diseases, M W. Sweetingham

Journal of the Department of Agriculture, Western Australia, Series 4

increased yield from wheat after lupins, obtained without the need for applied nitrogen, has led many farmers to adopt a 1:1 wheat-lupin rotation. One of the advantages of lupins is the cleaning effect they have by reducing wheat diseases such as septoria and yellow leaf spot and root diseases, in particular take-all.

Before the present research projext started, little was known about lupin root diseases, or what effect lupins grown in close rotation with wheat might have on the build-up of root disease of lupins.


Phomopsis-Resistanct Lupins : Breakthrough Towards The Control Of Lupinosis, W A. Cowling, J. G. Allen, P Mcr. Wood, J. Hamblin Jan 1986

Phomopsis-Resistanct Lupins : Breakthrough Towards The Control Of Lupinosis, W A. Cowling, J. G. Allen, P Mcr. Wood, J. Hamblin

Journal of the Department of Agriculture, Western Australia, Series 4

Attemots to control lupinosis in sheep have been thwarted by the unpredictable occurence of the disease in the field. The complex interaction of the toxin-producing fungus (Phomopsis leptostromiformis) with its host (the lupin plant), together with variable weather and paddock grazing conditions, have made it difficult to predict when stock are in danger of contracting the disease. The risk of lupinosis discourages many farmers from growing lupins, despite the many potential benefits of including them in crop rotations.

A team of Department of Agriculture plant breeders, plant pathologists, and animal scientists set out in the mid 1970s to find resistance …


Barley Breeding Update, P A. Portmann Jan 1986

Barley Breeding Update, P A. Portmann

Journal of the Department of Agriculture, Western Australia, Series 4

Barley production in Western Australia has increased over the past few years, peaking at 1.42 million tonnes in 1984. The European Economic Community, however, has flooded world markets for barley and over half of ourbarley was sold for feed to Saudi Arabia last year. Current prices therefore have declined as has the total area sown to barley in this State.

Despite this, the potential to increase barley yields is most promising. The Department of Agriculture has cross-bred lines in advanced stages of field testing which could increase yield by 10 per cent across the agricultural areas.

In the longer term, …


Phomopsis Infection Of Lupin Seed, D S. Petterson, P. Mcr. Wood Jan 1986

Phomopsis Infection Of Lupin Seed, D S. Petterson, P. Mcr. Wood

Journal of the Department of Agriculture, Western Australia, Series 4

Early reports of lupinosis in Western Australia implicated infected stems and leaves of the sandplain or W,A. blue lupin (Lupinus cosentinii) as the main source of toxicity.

After the introduction of low alkaloid varieties of L. augustifolius, lupinosis continued to oddur on stubbles but random testing of seeds showed only low levels of Phomopsis leptostromiformis infection.

However in 1976, scientists at the University of Western Australia who were evaluating the use of an all lupin seed ration for drought feeding sheep encounted lupinosis in one of their trials.Seven per cent of the seed used was found to be infected …


Rhizoctonia Patch Of Cereals, G C. Macnish Jan 1986

Rhizoctonia Patch Of Cereals, G C. Macnish

Journal of the Department of Agriculture, Western Australia, Series 4

Rhizoctonia patch is now widespread within Western Australia, having been recorded on all cereals and on a wide variety of other crops and pasture plants. Although the disease-as its name implies - looks spectacular in the field, the overall reduction in crop yield is probably small. However, its increasing frequency is causing considerable concern as the disease appears to be associated with minimum or reduced tillage systems.


Yellow Spot Of Wheat, R Loughman, J. M. Wilson, R. E. Wilson Jan 1986

Yellow Spot Of Wheat, R Loughman, J. M. Wilson, R. E. Wilson

Journal of the Department of Agriculture, Western Australia, Series 4

Yellow spot is a serious leaf disease of wheat in Western Australia. It also occurs in Queensland, New South Wales and South Australia. Yellow spot can appear as a severe leaf blight but generally the disease does not have the rapid epidemic development of wheat rust diseases. It builds up more slowly and is not as obvious in the crop, while caising appreciable yield loss.