ALLIGATOR WEED

Lalith Gunasekera,
Keith Turnbull Research Institute, Frankston, Tel. (03) 9785 0137

Alligator weed (Alternanthera philoxeroides) is one of the worst aquatic and terrestrial weeds in the world and is declared noxious in all Australian states. This plant has the potential to become a serious threat to waterways, agriculture and the environment.
Alligator weed originates from the Parana River system in Argentina. It has become widespread in tropical and warm temperate regions such as USA, Burma, Thailand, India, China, New Zealand and Australia. It was first recorded in Australia at Carrington near Newcastle, New South Wales in 1946 growing in ballast heaps dumped by wartime shipping. Alligator weed naturalised in different locations in New South Wales. However recent (1996) studies have identified Alligator weed grown for use as a vegetable in home gardens in all Australian states.

Alligator weed Alternanthera philoxeroides

Replacement vegetable Alternanthera denticulata

Vegetable Confusion
Alligator weed has similar appearance to another plant native to South America in the same family Amaranthaceae: Alternanthera sessilis (sessile Joyweed or Mukunuwenna) a leafy vegetable popular in Sri Lanka, India and west tropical Africa. Botanically this vegetable is completely different. However there seems to be confusion amongst some people between this leafy vegetable and Alligator weed growing in Australia.
Work with alligator weed in Queensland started in 1996. It was found in more than 30 backyard sites in Brisbane, 50 in Sydney and 675 sites in 125 suburbs in Victoria including country Victoria.

In 1997 an alligator weed eradication program began in Victoria. Three herbicides are being evaluated. The supply of an alternative vegetable is crucial to the success of the eradication campaign. Two Australian natives, Alternanthera nodiflora (Common Joyweed) and Alternanthera denticulata (Lesser Joyweed) have been evaluated. Chemical composition of these plants was also investigated.

The taste and flavour of these two native species have been accepted by the Sri Lankan community, the main nationality currently utilizing Alligator weed in Australia. 3000 replacement plants have been distributed to the Sri Lankan community. This program is still in progress. Alternanthera sessilis (Sessile Joyweed or Mukunuwenna) is also being distributed as a replacement vegetable for the Sri Lankan community in Queensland and New South Wales. This species however, is recorded as a serious noxious weed in other parts of the world.

WHITE or ORIENTAL RADISH *

White or oriental radish (Raphanus sativus) also known as 'lor pak' in Cantonese and 'cu cai tranh' in Vietnamese is an annual usually 30 to 60 cm high although it can grow up to 1.8 m when flowering. The mature leaves are large and can be upright or sprawling. They tend to be lobed with texture ranging from smooth and glossy to rough and hairy. Leaf colour varies from dark green to greenish-grey, sometimes with purple leaf stalks or purple splashes on leaves. Flowers can be white, pink or purple in colour. A typical Oriental radish is a long white cylindrical root which may grow to about 30 cm long and 10 cm in diameter slightly tapered at end. Others can be rounded in shape about 15 cm in diameter and 10-13 cm long. The world's largest radish, 'Sakurajima', a Japanese variety had a girth of 80 cm and 12 cm long. Oriental radish can weigh from 0.5 kg to 30 kg. There are two main groups: the white radish 'daikon' often associated with Japanese radish in Australia and the red and green fleshed varieties.

Nutritional Value In every 100g of fresh root there are:
92 g water 6 g carbohydrates 34 g phosphorus 0.02 mg carotene 0.04 mg Vit B2 30 mg Vit C	0.6 g protein 49 mg calcium 0.5 mg iron 0.02 mg Vit B1 0.5 mg niacin

Climate and Soil
The ideal growing temperature for white radish is about 20°C in rich, light, well-drained soil. Deep lightsoil is essential for long-rooted varieties. The soil should be manured for the previous crop rather than freshly manured. Crop rotation should be included in cultural practice to avoid build up of root nematodes.

Cultivation
Seeds should be sown 1 to 2 cm deep. If possible sow in sunken drills 4 cm deep to give the 'leggy' seedlings extra support. Sow thinly to make thinning easier. Small varieties should be spaced 7.5-10 cm and large varieties may need up to 40 cm apart each way. If growing in rows, space rows at least 35 cm apart.

Harvesting
Most varieties can be pulled for eating at various sizes during development.
The Chinese consider Oriental radish as a 'cooling', detoxifying vegetable with the ability to dissolve mucous. It is also recommended for conditions of indigestion caused by eating too much rich, fatty food. So it is cooked with fatty foods to provide balance and often for long periods, as in soup or braised dishes, to moderate its excessive cooling properties.

Preparation
Select heavy, unblemished radish. Inside, it should be solid (not fibrous), translucent white and pungently fragrant.
Wash and scrape the surface lightly. Chop, grate or shred as desired.

Cooking
Slice oriental radish paper-thin for use in salads. It can be pickled in vinegar with a little chilli and sugar. Braise and boil it as you would potatoes. It can be used to make winter soups and stews - it withstands long cooking without disintegrating.

Domestic Market Information
The following graph is based on the retail price survey conducted in Melbourne from March 1995 to March 1998 and Sydney 1996 wholesale price survey for oriental radish:

* [For additional information see also our Vegetable Thesaurus]

PICK FROM THE BOOK SHELF

In each newsletter we will present a brief summary on one of RIRDC's publications on Asian Foods. This month's issue looks at

Food Retailing in South East Asia - Exploring the Opportunities
Dr Alan Treadgold, Australian Centre for Retail Studies, Monash University
RIRDC Research Paper 95/10, $40 ($6 p&h) 160 pages

Focuses on the current nature of and the changes taking place in food retailing in Indonesia, Malaysia, Singapore, Taiwan and Thailand, with particular reference to their organisational structures. Provides practical advice on how, where and with what products to access Asian food distribution chains.

The book can be purchased from
Rural Industries Research and Development Corporation (RIRDC)
P O Box 4776, Kingston, ACT 2600, Phone: (02) 6272 4819, Fax: (02) 6272 5877
Webpage: http://www.rirdc.gov.au/

For more RIRDC publications see our first 'Asian Foods' Newsletter.