PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Description of some weeds species (contd)
Dicotyledons - broadleaved weeds – .WOODY WEEDS.
BLACKBERRY (Rubus fructicosa)
Type Introduced perennial deciduous shrub for
berry jams, etc. Dense thicket-forming shrub
from 2-6 m. Noxious weed in ACT, NSW,
Vic, Qld, SA, Tas and WA. WONS, ENV,
Garden Escape. Often common along
waterways.
Leaves Usually dark green on the upper side and
lighter green, often with whitish hairs on the
underside; alternate; 3 or 5 toothed, oval to
ovate leaflets with short prickles on leaf
stalks or undersides of veins.
Flowers White or pink, 2-3 cm in diameter formed in
clusters at the end of short branches, 5 petals.
Fruit A berry changing colour from green to red to
black as it ripens, 1-3 cm in diameter
consisting of an aggregate of juicy segments
each containing 1 seed.
Seeds Light to dark brown, sometimes triangular,
2-3 cm long, deeply and irregularly pitted.
Roots Most roots occur in the top 20 cm of soil but
a few to 1 m deep. There is a well defined
crown at ground level.
Spread By seed spread by birds, foxes, creeks and
rivers. Dislodged stem-tip rooting and root
suckering, crowns, root pieces and stem
fragments, by machinery, slashing and during
removal.
Rosaceae
Flower, berry clusters
and leaves
BITOU BUSH, BONESEED (Chrysanthemoides monilifera) Asteraceae
Type Perennial erect woody shrub up to 3 meters
tall. Noxious weed in NSW, Vic, Qld, SA
and WA. WONS, ENV, Garden Escape.
Stems woody much branched, upper stems
often purplish.
Leaves Alternate, 3-8 cm long, ovate to spoonshaped,
tapering at base, smooth-edged or
slightly toothed. Shortly stalked, practically
hairless, except for a cottony growth on
young leaves.
Flowers Florets, bright yellow on shortly stalked
heads, 2-3 cm in diameter clustered at the
ends of branches, petals 5 or 6 occasionally
8 per head. Chrysanthemum-like hence
botanical name Chrysanthemoides.
Fruit Berries are round, green, 5-7 mm in diameter
and hang in clusters at the end of branches,
during ripening they become black.
Seeds Seeds are globular or ovoid, 5-7 mm long
and 3-4 mm in diameter, very hard and
bonelike in color (boneseed). One mature
bush can produce 50,000 seeds in 1 season.
Most seeds remain viable for 2-5 years.
Roots Shallow, no distinct tap root. Rotundata roots
on prostrate stems in contact with soil.
Spread By seed, was introduced as a sand dune
Leaves and flower cluster
stabilizer, dumped with rubbish. Birds,
rabbits, foxes and cattle spread seed in their
dropping. Contaminated gravel. Seed and
ripening fruits by running water.
422 Weeds - Biology, classification and identification