Three-horned Bedstraw

Galium tricornutum Dandy

Synonyms - Galium tricorne Stokes

Family: Rubiaceae.

Names:

Galium is from the Greek gala meaning milk because it was used to curdle milk.
Tricornutum means three horns.
Three-horned Bedstraw

Other names:

Cleavers
Corn Cleavers (Turkey)
Rough Corn Bedstraw.

Summary:

An annual herb with a distinctive sticky feeling due to fine prickles on the stems and leaves. It has rings of 6-8 leaves that are hairless on the upper surface but has fine spines on the edges that are backward pointing near the base and forward pointing near the tip of the leaf. The small, white, 4 petalled flowers occur July to November and set minutely dimpled, paired, globular fruit that are usually in sets of three on short curved stalks. The stems are prostrate or scrambling and climbing, square in cross section with backward pointing prickles on the corners.

Description:

Cotyledons:

Two. Oval. Hairless. Tip indented?.

First leaves:

Oval, in groups or whorls of 4. Tip pointed. Hairs on edges.

Leaves:

Arranged in umbrellas of 4-8 leaves around stem.
Stipules -
Petiole - Absent.
Blade - Oval, 15-30 mm long. Backward pointing prickles on the edges near the base and forward pointing prickles near the tip. Midrib extends beyond the tip of the leaf as a fine spine. Hairless on the upper surface. Tip pointed. Edges parallel. Base tapered.

Stems:

Erect, square, wiry, stiff, long, up to 500 mm, stout. Backward pointing prickles on the corners. Branching from the base.

Flower head:

Axillary and terminal cyme, that is usually 3 flowered and on a stalk (peduncle) that is shorter than the leaves. Individual flower stalks (pedicels) are curved.

Flowers:

Small.
Bracts -
Ovary -
Sepals - None
Petals - 4, creamy white and spreading.
Stamens -
Anthers -

Fruit:

Fruitlets globular, 4 mm long x 8 mm wide, minutely dimpled. On a curved stalk. 2 seeds per pod.

Seeds:

Retained in fruitlets. Globular. Surface minutely dimpled with a circular orifice with a raised rim that looks like a doughnut. 15-35 seeds per plant in cereal crops (494).

Roots:

Taproot.

Key Characters:

Fruit tuberculate and kidney shaped. Stems stout. 6-8 leaves in a whorl. Short peduncles. Fruiting pedicels, stout, recurved and usually 3.

Biology:

Life cycle:

Annual. Germinates autumn/winter. Flowers in October-November.

Physiology:

Strong competitor but sensitive to competition from neighbouring plants (495).
Leaf area of 1.59 cm2 on 37 g plants (496).

Reproduction:

By seed.

Flowering times:

October to November in SA.
July to November in WA.

Seed Biology and Germination:

Seed coat probably causes dormancy (497).
Emergence was <18% at constant temperatures of 5-30 deg C (498).
Emergence is <18% with dark and 12 hour light/dark conditions (498).
Sulphuric acid increased germination from 18% to 33% and sulphuric acid + GA increased it to 63% (498).
Emergence was 52, 28,12 and 1% from seed sown at 2, 5, 10 and 15 cm deep over 20 months. Viable seed remaining was <4% (498).
KNO3 treatment decreased germination (497).
In cereal crops emergence varied from 60-80% and seedling survival from 9-95% depending on the year in Spain (494). Seedling emergence was 16-31% under minimum tillage and 1-14% under zero tillage. Seed loss was 100% under zero tillage and less under minimum tillage indicating seed predation was occurring (499).

Vegetative Propagules:

None.

Hybrids:

Allelopathy:

Population Dynamics and Dispersal:

Origin and History:

Europe and central Asia.

Distribution:

NSW, SA, VIC, WA.
Introduced to WA (Boddington) as a contaminant of seed from the USA and was eradicated.
Found at Mt Barker in 2001 and eradicated.
Found at Cranbrook in 2005 and eradicated.
Found at Cordering near Darkan in 2002, Hines Hill near Merredin in 2004 and eradication programs were commenced.
Algeria (500), Cyperus (388), Greece (501), Spain (502), Turkey (503, 504), West Asia (505), Yugoslavia (506).

Courtesy Australia's Virtual Herbarium.

Habitats:

Climate:

Temperate.

Soil:

Plant Associations:

Significance:

Beneficial:

Does not host Root Lesion Nematodes (Pratylenchus neglectus or thornei) (64).
Extracts reduce the growth of Verticillium dahliae (507).

Detrimental:

Weed of crops like small grains (506), chickpea (508), lentils (508), olives (509), potatoes (388)
Contaminates the grain of wheat (502), pulses (510) and canola.
Host for tomato spotted wilt tospovirus (TSWV) (511).

Toxicity:

Not recorded as toxic.

Legislation:

Under eradication in WA.
Noxious weed of part of SA and TAS

Management and Control:

2,4-D
Applied late post em provided good control in cereals (512). Overseas results with 2,4-D have been poor.
Aclonifen
2.4-3 kg/ha pre em gave good control in potatoes in Cyprus (388).
Alachlor (Lasso®)
Alachlor + 1.5 kg/ha flurochloridone pre em gave good control in potatoes in Cyprus (388).
Amidosulfuron (Atlantis® in the USA)
Applied early post em gave good control in wheat and barley (512).
Bentazone
1000-1500 g/ha on plants to 30 cm gave good control in potatoes in Cyprus (388).
Poor control in pulses (512).
Bromoxynil
Poor control in wheat in Algeria (500).
Bromoxynil + Dicamba + MCPA ester (Broadside)
196 + 56 + 392 g.a.i./ha applied early post em to tillering of wheat and barley gave >90% control (513, 512).
Bromoxynil + diflufenican (Jaguar)
Applied early post em gave good control in wheat and barley (512).
Bromoxynil + MCPA ester
Applied post em provided variable control in cereals (512).
Bromoxynil + MCPA ester + metsulfuron-methyl
Applied post em provided variable control in cereals (512).
Chlorsulfuron (Glean®)
19 g.a.i./ha applied early post em to tillering of wheat and barley gave >90% control (513).
Applied post em provided variable control in cereals (512) and poor control at 9 g.a.i./ha post em in Oats at Cranbrook (Moore, 2005).
Dicamba
140 g.a.i./ha applied early post em to tillering of wheat and barley gave >90% control (513).
Dicamba + MCPA ester
112 + 476 g.a.i./ha applied early post em to tillering of wheat and barley gave >90% control (513).
Diflufenican (Brodal®)
Poor control in pulses (512).
Diflufenican + MCPA ester (Tigrex)
25 + 250 g.a.i./ha applied early post em to tillering of wheat and barley gave >90% control (513).
Flumetsulam (Broadstrike®)
Applied post em in chickpeas and field peas gave effective control of bedstraw seed production (512).
Applied early post em gave good control in wheat and barley (512).
20 g.a.i./ha early or later post em on peas gave 80-90% control (513).
Fluroxypyr (Starane®)
175-250 g.a.i./ha applied early post em to tillering of wheat and barley gave >90% control (513, 512).
Imazethapyr (Spinnaker®)
20-100 g.a.i./ha post plant pre em on peas gave 80-90% control (513, 512).
20-100 g.a.i./ha early post em peas gave 80-90% control (513, 512).
Applied pre em provided adequate control in faba beans, chickpeas (512).
Imazethapyr + metribuzin
20 + 146-197 g.a.i./ha early post em on peas gave 80-90% control (513).
Linuron
4 kg/ha pre em provides better control in sunflowers than standard herbicides (514).
Metribuzin (Lexone®, Sencor®)
Poor control in pulses (512).
Metsulfuron-methyl (Ally®)
Applied post em provided variable control in cereals (512).
Pyridate (Tough)
Poor control in pulses (512).
Rimsulfuron (Titus®)
10-20 g.a.i./ha on plants to 30 cm gave good control in potatoes in Cyprus (388).
Simazine
Poor control in pulses (512), olives (509)
Terbutryn (Igran®)
450-525 g/ha terbutryn + terbuthylazine pre em gave good control in potatoes in Cyprus (388).
Terbutryn + triasulfuron
300 + 10 g.a.i./ha applied early post em to tillering of wheat and barley gave >90% control (513).
Tribenuron-methyl (Express®)
Good control in wheat in Algeria (500).

Thresholds:

In WA it is very low because it is a declared plant.
For early germinating plants a few per square metre can lead to significant grain contamination. A late germination often occurs.
The threshold for economic spraying is probably around 1-2 plants/m2.

Eradication strategies:

Cereal growing areas
A sequence of IT (Clearfield®) crops is preferred using minimum or zero tillage.
For example;
Year 1; IT wheat treated with knockdown plus 20 g/ha OnDuty® (or equivalent) pre planting then 20 g/ha OnDuty® plus 1% oil at the 4 leaf stage of the crop and 20 g/ha OnDuty® plus 1 L/ha Starane®200 plus 1% oil at the flag leaf stage if necessary. Use a chaff cart. Burn stubble.
Year 2; IT canola treated with a knockdown plus 40 g/ha OnDuty® pre planting then 20 g/ha OnDuty® at the 4 leaf stage and repeat at the bolting stage if necessary.
Year 3; Field Peas treated with a knockdown plus 70 g/ha Spinnaker® pre planting followed by 70 g/ha Spinnaker® plus wetting agent 6 weeks later (Add 25 g/ha Broadstrike® to this mix if there have been any survivors from the pre plant spray).
Year 4; IT wheat as in year 1.
Year 5; Legume based pasture treated with 25 g/ha Broadstrike® plus 50 g/ha diuron900 in June and repeated in early September.
If IT crops cannot be grown
Wheat, barley, oats and triticale
Apply 1 L/ha Starane® at the 4 leaf stage of the crop and repeat at the flag leaf stage.
Field pea and chickpea
Apply 150 g/ha Spinnaker® pre plant then 25 g/ha Broadstrike® plus 50 g/ha Spinnaker® plus 1% oil in August.
Faba Bean
Apply 150 g/ha Spinnaker® pre plant then 45 g/ha Raptor® plus 45 g/ha Spinnaker®700 at the 6 leaf stage of the crop.

Avoid growing lupins. If three horned bedstraw found in lupins then Eclipse® may suppress it.
Avoid growing canola. If three horned bedstraw found in canola then dicamba may suppress it.

Legume based pastures
Treat with 25 g/ha Broadstrike® plus 50 g/ha diuron900 in June and repeat in early September each year for at least five years.
Grass pastures
Apply 1 L/ha Starane®200 plus 1% oil in June and repeat in September.
Lucerne (greater than 2 years old)
Try hexazinone.
Fence lines, roadsides, around buildings and other non productive areas.
Apply 6 L/ha Arsenal®.

Bushland
Apply 300 g/ha Spinnaker®700 or 25 g/ha Broadstrike® plus 50 g/ha diuron900 plus 1% oil in June with a mister or by aircraft.

Permits may be required for eradication strategies.

Herbicide resistance:

Biological Control:

Related plants:

Cleavers (G. aparine) has straight fruiting pedicels (stalks) and has hairs on the upper surface of the leaves and hooked spines on the seed.
Slender Bedstraw (G. divaricatum)
Small Bedstraw (G. murale)
False Cleavers (G. spurium) has straight spines to small pegs on the seed.

Plants of similar appearance:

Three-horned Bedstraw can be distinguished from Field Madder by the shape of the cotyledon in the young stage, and in more advanced plants by the size of the leaves and the number in a whorl, and the colour of the flowers. Three-horned Bedstraw has hairs on the edges of the leaves that generally point backwards (away from the leaf tip) whereas Field Madder has hairs that point forward.
Slender Myoporum (Myoporum caprarioides Benth.) is a native plant
Colour photos and identification tips are in 384.

References:

Auld, B.A. and Medd R.W. (1992). Weeds. An illustrated botanical guide to the weeds of Australia. (Inkata Press, Melbourne). P218.

Black, J.M. (1965). Flora of South Australia. (Government Printer, Adelaide, South Australia). P800. Diagram.

Hussey, B.M.J., Keighery, G.J., Cousens, R.D., Dodd, J. and Lloyd, S.G. (1997). Western Weeds. A guide to the weeds of Western Australia. (Plant Protection Society of Western Australia, Perth, Western Australia). P210.

Lamp, C. and Collet, F. (1990). A Field Guide to Weeds in Australia. (Inkata Press, Melbourne).

Lazarides, M. and Hince, B. (1993). CSIRO handbook of economic plants of Australia. (CSIRO, Melbourne). #571.6.

Wilding, J.L. et al. (1987). Crop weeds. (Inkata Press, Melbourne). P144. Diagrams. Photos.

Figures in brackets, for example (384), refer to the main reference database. Contact HerbiGuide for more information.

Acknowledgments:

Collated by HerbiGuide. Phone 08 98444064 or www.herbiguide.com.au for more information.