PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
Description of some weeds species
Dicotyledons (broadleaved weeds) – .ROSETTES.
(some weeds are only rosettes at certain stages of growth)
CAPEWEED (Arctotheca calendula)
Type Annual or biennial herb. Declared
noxious weed in Tasmania. Agricultural
weed, can be abundant in waste places,
pasture, taints milk. Host for redlegged
earth mites.
Leaves Deeply lobed to the midrib. Thick, fleshy,
very hairy, silvery gray-green above,
silvery white down beneath. Rosetted
with no milky sap.
Flowers Solitary, single yellow with black or
orange center, on singular stems.
Seeds Small nutlets enclosed in a woolly ball.
Roots Strong fibrous roots.
Spread By seed.
Asteraceae
Flowering plant, yellow flowers
DANDELION (Taraxacum officinale)
Type Persistent but shortlived, herbaceous
perennial herb. Garden weed, waste
places, invades lawns. Often confused
with catsear (Hypchaeris radicata) which
has thinly branched flower stems (see
front cover).
Leaves Irregularly toothed, smooth shiny light
green with milky sap (latex), rosette.
Flowers Solitary double yellow daisy on single
hollow stem.
Seeds With a pappus. Widespread in temperate
Australia.
Roots Thick, deep fleshy tap root.
Spread By seed and by cut-up pieces of root;
spread by cultivation.
Asteraceae
Flowering plant, yellow flowers, tap root
Weeds - Biology, classification and identification 419