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Biological Control Of Doublegee : Israeli Weevil Could Help Fight Doublegee, John Scott, Paul Yeoh

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

Since its deliberate introduction from South Africa as a salad vegetable in 1830 the doublegee has spread to become a major weed throughout much of Australia.

It is one of the most serious weeds of crops and pastures in Western Australia, smothering other more useful plants while young, and troubling both humans and animals with its sharp spiny seeds when mature.

Using biological control techniques, scientists are now attacking it and related docks in three ways - with an aphid, a weevil and a fungus.

Within a few years it is hoped that while still present, the doublegee will be …

Biological Control Of Doublegee : Doublegee Decline And The Dock Aphid, John Scott, Francoise Berlandier, Kristy Hollis

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

Since 1990 farmers in the Western Australian wheatbelt have been reporting doublegee plants that appear to be diseased, stunted and producing poorly formed fruit (the spiny casing around the single doublegee seed). Often no obvious cause of this decline in plant health is apparent. Experiments carried out in 1990 showed that an aphid, which feeds hidden in the growing tips of doublegee stems and in young distorted leaves, is the most likely cause. This North American aphid, the dock aphid (Brachycaudus rumexicolens), arrived in WA in 1987. It appears to only feed on docks, doublegees and related plants and is …

Biological Control Of Doublegee : Fungi May Be Another Weapon, Roger Shivas, John Scott

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

A fungus has been assessed both in Australia and South Africa since 1989 for its potential to control doublegee.

Under optimal environmental conditions it causes a severe stem blight which ultimately kills the plant. It also infects seeds, and caused up to 30 per cent mortality at a field site near Badgingarra.

Hopes to develop the fungus as a mycoherbicide (fungal killer of plants) have had to be dropped because it produces a potent toxin but it is still contributing to control in the field.

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.

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.