Species name

Common name

Current weed status

References

Weed control techniques

Opuntia stricta top

prickly pear

l, P3

p,n

The introduced Cactoblastis moth (along with a cochineal bug) is one of the most effective biological control agents ever released, limiting prickly pear to small isolated populations.

Panicum maximum

guinea grass

s

c,s

Hand removal is effective for small populations Larger infestations can be slashed or burnt, followed by foliar spray with glyphosate or hand removal. Shading is the best long term solution.

Parkinsonia aculeata

parkinsonia

s, P2

p,n,c

Mechanical removal followed by foliar spray of regrowth with triclopyr/picloram. Basal bark or cut stump application of triclopyr/picloram. Beetles and a bug have been introduced, but their impact is unknown as yet.

Parthenium hysterophorus

parthenium weed

m, P2

p,n

CAUTION: This plant can cause severe dermatitis and hay fever. Pasture spelling and careful management to avoid overgrazing limit entry and spread. Machinery, stock, feral animals and people can all spread seed. Strict quarantine procedures, including washing down of equipment used in infested areas, will limit spread. Foliar spray with glyphosate, picloram or 2,4-D. Biological control, using 7 insects and a fungal rust, has so far had limited success.

Passiflora foetida

stinking passionfruit

s

s

Hand removal (ensuring roots are also removed), herbicide susceptibility unknown.

Passiflora suberosa

corky passionfruit

s

s

Hand removal (ensuring roots are also removed), herbicide susceptibility unknown.

Pistia stratiotes

water lettuce

l, P3

p,n

Mechanical or hand removal. Two introduced weevils provide good control in many areas. Glyphosate has been used successfully, but is undesirable in waterways.

Psidium guajava

guava

l

Injection, basal bark or cut stump application of triclopyr/picloram probably effective

Ricinus communis

castor oil plant

m

p,n,c

Mechanical or hand removal, foliar spray of small plants with glyphosate or 2,4-D, basal bark or cut stump application of larger plants with triclopyr/picloram.

Salvinia molesta

salvinia

m, P3

p,n,c

Biological control with an introduced weevil provides excellent control of large infestations. Small populations can be removed mechanically or by hand.

Samanea saman

rain tree

l

Injection, basal bark or cut stump application of triclopyr/picloram probably effective

Schinus terebinthifolia

Brazilian pepper tree

l

s

Hand removal of young plants. Injection, basal bark or cut stump application of triclopyr/picloram probably effective on larger plants.

Senna alata

candle bush

l

n,c

Hand removal effective if roots also removed. Slashing at flower stage prevents seed set. Foliar spray or cut stump application with triclopyr/picloram probably effective

Senna occidentalis

coffee senna

l

n,c

Hand removal, foliar spray with triclopyr/picloram, 2,4-D/picloram or glyphosate

Sida rhombifolia

Paddy’s lucerne

l

n,c

Mechanical or hand removal, foliar spray with glyphosate. Numerous insects have been introduced, but their impact is unknown at this stage.

Solanum seaforthianum

Brazilian nightshade

l

Hand removal, herbicide susceptibility unknown.

Solanum torvum

devils fig

l

Foliar spraying with glyphosate, or basal bark or cut stump application with triclopyr/picloram probably effective.

Spathodea campanulata

African tulip tree

l

Injection, basal bark or cut stump application of triclopyr/picloram probably effective

Stachytarpheta jamaicensis

snake weed

m

p,n

Common in overgrazed pastures. Foliar spray with glyphosate or 2,4-D most effective on young plants. Pasture spelling and management to avoid overgrazing are important in limiting entry and spread of snakeweed.

Stylosanthes humilis

Townsville stylo

m

Hand removal, herbicide susceptibility unknown.

Syzygium cumini

Javan plum

l

Injection, basal bark or cut stump application of triclopyr/picloram probably effective

Tamarindus indica

tamarind

l

Injection, basal bark or cut stump application of triclopyr/picloram probably effective

Tecoma stans

yellow bignonia

m

Injection, basal bark or cut stump application of triclopyr/picloram probably effective

Themeda quadrivalvis

grader grass

s

n,c

Foliar spray with glyphosate, before annual seed set. Fires and overstocking increase infestations.

Thevetia peruviana

yellow oleander

m

Injection, basal bark or cut stump application of triclopyr/picloram probably effective

Thunbergia spp

thunbergia

m, P2

p,n,c

Foliar spray with imazapyr (eg Arsenal 250A) will kill aerial shoots and underground tubers. Young plants can be controlled with glyphosate or 2,4-D.

Tithonia diversifolia

Japanese sunflower

m

c,s

Hand removal, foliar spray with 2,4-D, basal bark or cut stump application of triclopyr/picloram or fluroxypyr

Tridax procumbens

tridax daisy

l

s

Hand removal, foliar spray with 2,4-D

Triumfetta spp

chinese burrs

l

c

Hand removal, slashing, foliar spray with 2,4-D (or glyphosate?)

Urena lobata

urena burr

l

c

Hand removal, slashing. Young plants can be controlled by foliar spray with 2,4-D (or glyphosate?)

Urochloa mosambicensis

sabi grass

m

Slashing, foliar spray with glyphosate probably effective

Wedelia trilobata

Singapore daisy

m

s

Hand removal, mowing very close to ground, foliar spray with metsulfon methyl (eg Brush-off)

Xanthium pungens

noogoora burr

l, P3

p,n,c

Hand removal or controlled burning before seed set. Foliar spray with glyphosate or 2,4-D, most effective on young plants. Introduced insects (seed fly, stem boring beetles and stem galling moth) and a fungal rust provide some control in moist tropical regions.

Zizyphus mauritiana

chinee apple

s, P3

p,n,c

Heavy infestations can be cleared with a bulldozer, and regrowth controlled with triclopyr/picloram. Basal bark or cut stump application of triclopyr/picloram effective on individual trees.