PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Description of some weeds species (contd)
Monocotyledons (narrowleaved weeds) – GRASS WEEDS. (contd)
(Family Poaceae)
SUMMER GRASS (Digitaria sanguinalis)
Type Annual summer grass weed.. May disappear
with the onset of winter. Do not confuse
with paspalum. Sometimes called
crabgrass. Very common in temperate areas
occurs in all states especially where summer
water is available, as in suburban gardens.
Leaves Rolled in bud leaf, medium texture. Soft,
gray-green. Ligule very long, parchment,
white, pink, tipped. Hairy sheath and
reddish-brown stems.
Flowers Fine widely branched spikelets. Whorled
stems.
Seeds Seeds profusely.
Roots Fine, vigorous, fibrous from extensive
stolons.
Spread By seed. Plant more-or-less lies on the
ground and tends to root at the stem nodes.
Leaves, inflorescences, stolons
and roots
WINTER GRASS (Poa annua)
Type Annual grass weed, but can be a short-lived
perennial depending on the situation.
Cosmopolitan, occurs widely in temperate
areas of Australia. On paths and similar
situations it is very small or almost prostrate
but can grow up to 30 cm high. Mainly a
winter and spring weed which disappears
with the onset of summer. Can withstand
close mowing in lawns and turf. Weed of
cultivation, lawns and wasteland.
Leaves Folded in bud leaf, light green, fine texture
with crimped blades. Long parchment ligule.
Flowers Short panicles or spikelets.
Seeds Seeds small and flattened.
Roots Fine, short, fibrous from tillers.
Spread By seed.
Leaves, flowers and roots
424 Weeds - Biology, classification and identification