Plant Pathology Commons^™

New Leaf Rust Helps To Control Blackberry, Jonathon Dodd, Sandy Lloyd

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

The release of spores of the blackbeny leaf rust in spring 1991 marked the second attempt in Western Australia at controlling weedy blackberries with a biological agent. The strain of rust now being used is expected to be more effective than the one released in the 1980s.

This article describes the techniques used for rearing and releasing the fungus and illustrates the effects of the rust on blackbeny.

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. …

The Pollen Exostructure Of Striga (Scrophulariaceae), Mark A. Deleonardis

Biological Sciences Theses & Dissertations

In this survey, the pollen exostructure of 13 Striga species was examined using light microscopy and scanning electron microscopy. Two of the 13 species were also observed by transmission electron microscopy to assess major differences in exine composition. Striga pollen is consistently spherical to oblate, isopolar, tectate, and three or four colpate. Sculpturing may be psilate, psilate-perforate, finely rugulate, or coarsely rugulate. The equatorial width of the species surveyed ranged from 15 to 30 micrometers. It is concluded that variation in Striga pollen sculpturing, aperture structure, and size support the current taxonomy of the genus.

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, …

Germination And Host Range Of Branched Broomrape (Orobanche Ramosa) From Texas, Robert D. Coffin

Biological Sciences Theses & Dissertations

The effect of temperature on the germination of Orobanche ramosa L., branched broomrape, was investigated by dividing the physiological stages leading to germination into discrete events: pretreatment, a period when the seed becomes receptive to stimulant, and posttreatment, when stimulant application (GR-24) induces germination. Seed was pretreated and posttreated at 16 different temperature combinations. Optimal pretreatment was at 15°C and 18°C, maximum posttreatment at 18°C. Highest germination was obtained by pretreating and posttreating seed at 18°C, lowest at 24°C. The effect of different pretreatment regimes was tested. Seeds were pretreated over moist filter paper and in soil for Oto …

A 'Natural Herbicide' Against Calotrope?, A H. Cheam

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

Buffel grass produces a chemical compound which is toxic to the growth of calotrope seedlings, a declared weed in Western Austrsalia north of the 26th parallel. This new discovery id highly significant in view of the increasing emphasis now placed on weed management as opposed to weed control and the desire to use fewer pesticides.

Germination And Haustorial Development In Orobanche Minor Smith (Orobanchaceae), David L. Spelce

Biological Sciences Theses & Dissertations

Orobanche minor Smith is an introduced root parasite that is known to attack some commercial crops. Germination occurs only after a preconditioning period involving moisture which must be followed by a chemical stimulant produced by the host root. Strigol and strigol analogs (GR-compounds} have been reported to germinate some species of Orobanche. Statistical tests indicate a significant difference between the effectiveness of strigol, GR-7 and GR-45 (P = 0.001).

The embryo is an undifferentiated mass of cells. During germination, the radicular pole of the embryo differentiates into the radicle, while the plumular pole remains undifferentiated. The radicle forms the primary …

Septoria Diseases Of Wheat, A. G. P. Brown

Experimental Summaries - Plant Research

The Effect of Septoria nodorum on Yield of 125 Wheat Cultivars. The aim of this experiment was as described for that of 1976. There were some modifications to the treatments which were as follows: (a) Most of the cultivars were 'new' and (b) Three levels of Septoria attack were set up:- 1. Low: cover sprayed throughout the season with the fungicide Difolatan. 2. Moderate: inoculated with Septoria three times, followed at heading out by cover spraying with Difolatan. 3. Severe: inoculated four times no fungicide. The 125 entries were sown as hill plots with the three Septoria environments as main …

Evaluation Of The Systemic Nematicide Phenamiphos To Control The Nematode Anguina Sp In Toxic Ryegrass Pasture, B A. Stynes

Experimental Summaries - Plant Research

Field trials done in 1974 showed that phenamiphos could be used to control Anguina sp. and suggested that low rates may be effective with critical timing of applications. These possibilities were investigated in 1975. Locality - Katanning - F. Quartermaine and c. Butterworth. Gnowangerup - J. Griffith. Tables 1 and 2 show the absolute levels of nematodes in ryegrass seed and the density of nematodes per unit area of pasture after treatment with phenamiphos. All rates of nematicide reduced the level and density of nematodes; the highest rate being slightly more effective. The spray schedule including sprays in July and …

Spray-Graze : The Answer To Weeds In Pastures, Geoffrey A. Pearce

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

W.A. Department of Agriculture research leads to a new technique for weed control in pastures.

The trials which led to the development of the spray-graze technique of weed control started in Western Australia in 1966.

Since 1969, spray-graze has been tried in other States of Australia and is now recognised as the most practical method of controlling many pasture weeds.

Smooth-Stemmed Turnip, B J. Quinlivan, A. C. Devitt

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

Cruciferous weeds are common throughout the agricultural areas of Western Australia. They include wild turnip, wild mustard, wild radish, charlock and raphistrum weed or short fruited turnip.

Another one—tentatively named smooth-stemmed turnip—has recently been sighted. Its exact weed potential will not be known for some years, but it is likely to spread through the south coastal districts where the climate and sandy surfaced soils favour its growth.

Rapeseed. 1. Establishing A Healthy Crop, M L. Poole, M. G. Mason

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

No abstract provided.

The Control Of Algae, G R W Meadly

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

CONDITIONS in areas of still, stored water in Western Australia can easily become ideal for the development of algae and control measures may become necessary in farm dams and swimming pools.

Net Blotch Of Barley, W A. Shipton

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

NET BLOTCH is the most prevalent disease of barley in Western Australia, and is capable of reducing yields considerably.

It is caused by the fungus Pyrenophora teres Drechsl.

The Elimination Of Cultivation In Apple Orchards : A New Approach To Orchard Soil Management, S E. Hardisty

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

THE idea of eliminating cultivation in orchards suggests a reversal of accepted local practice in orchard soil management—but there is plenty of evidence to show that a noncultivation system has much in its favour.

In this article the advantages and disadvantages of the three main forms of orchard soil management are discussed and experimental evidence is presented in support of noncultivation.

An alternative method, "winter sod" culture, is proposed for irrigated orchards.

White Rust Of Gerberas, R F. Doepel

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

WHITE rust has proved to be a most damaging fungal disease of Gerberas.

Frequent fungicidal sprays are recommended for susceptible varieties in late winter and spring.

Control Of Bamboos, Department Of Agriculture, Western Australia

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

Bamboos can be controlled by spraying with a solution containing 2,2-DPA.

Control Of Perennial Grasses, Department Of Agriculture, Western Australia

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

Perennial grasses such as paspalum, kikuyu and couch can be controlled by spraying with a solution containing 2,2-DPA.

This is a non-poisonous powder which is sold under a variety of trade names.

Weeds In Lawns. 2. The Control Of Weeds In Lawns, Geoffrey A. Pearce

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

M OST lawns have weeds growing in them at some time during the year and in some lawns weed control becomes a major problem.

To the many people who like to keep a weed free turf it is therefore encouraging to know that nearly all weeds can be controlled with herbicides.

Diseases Recorded On Native Plants, Weeds, Field And Fibre Crops In Western Australia, G C. Macnish

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

This list is divided into three sections, the first dealing with native plants, the second with weeds (except grasses) and third with field and fibre crops.

Take Care Of Young Fruit Trees, R G. Cahill

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

Young fruit trees need good care if they are to grow well and produce good crops in later years.

Bridgetown Horticultural Instructor, R. G. Cahill, gives these hints for orchardists establishing young trees.

Although they take little effort to put into practice they will pay off well in the future.

Diseases Recorded On Cereals, Grasses And Pasture Legumes In Western Australia, S C. Chambers

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

This list constitutes a revision of portion of the census published by Came (1925) and supplemented by the same author in 1927.

It also contains records of diseases identified in the period between these earlier publications and December 31, 1959.

The list is divided into two sections, the first dealing with pasture legumes and the second with cereals and grasses.

The sections are arranged alphabetically according to the botanical names of the host plants. In general, the viral, bacterial, fungal and nematodal diseases and physiological disorders are listed in that order.

Seed Storage In Relation To Germination, G R W Meadly

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

WE are often asked how long seed can be stored and remain suitable for sowing.

There is no single answer as the period depends on a number of factors, including the type of seed, its condition at the time of storing and the nature of the storage.