PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
BUGS; HOPPERS; APHIDS, LERPS,
MEALYBUGS, SCALES, WHITEFLIES
Summary - Some exceptions
BUGS
HOPPERS
SOME DISTINCTIVE FEATURES
1.Thickened region on forewing.
2.Wings held flat over body, tips
usually overlap.
3.Antennae often long and
conspicuous, jointed.
4.Sucking beak arises from front part of
the head.
5.Some produce an offensive odour if
disturbed, eg stink or shield bugs.
1.Forewings same through out, same
texture.
2.Wings usually held roof-wise over
body.
3.Antennae mostly short but may be
long.
4.Sucking beak arises from hind part of
head.
PLANT DAMAGE
DIRECT SUCKING DAMAGE.
LEAVES Chlorotic mottling, eg lace
bugs
Wilting, eg bronze orange
bug, harlequin bug
Spots, eg acacia spotting bug
FRUIT Distortion, eg apple dimpling
FLOWERS bug, green mired bug
Marking, eg green vegetable
bug
SHOOTS Wilting, eg crusader bug,
Rutherglen bug
INDIRECT DAMAGE.
Disfigurement with frass, azalea lace
bug.
BENEFICIAL EFFECTS.
Some bugs are beneficial, eg assassin
bugs.
DIRECT SUCKING DAMAGE.
LEAVES Mottling, eg apple leafhopper
Wilting, eg passionvine
hopper
INDIRECT DAMAGE.
Secrete honeydew.
Some transmit virus & virus-like
diseases, common brown leafhopper
transmits tomato big bud
phytoplasma.
APHIDS
1.Soft, globular body (enlarged central
portion of abdomen), up to 8 mm
long. Variable in colour.
2.Cornicles often present towards end
of abdomen.
3.Wingless or winged with wings
usually held vertically above body.
4.Wings same texture.
5.Unusual life cycle:
Often complex and variable
Eggs or live young
Parthenogenesis or sexual
reproduction
DIRECT SUCKING DAMAGE.
LEAVES Death, eg green peach aphid
Distortion, eg cabbage aphid
Galls, eg grape phylloxera
FLOWERS Distortion, eg rose aphid,
BUDS
FRUIT
STEMS
TRUNK
ROOTS
black peach aphid
Distortion, eg green peach
aphid
Fruit fall, eg woolly aphid
Death of shoots (dieback), eg
black peach aphid
Shoot distortion, eg black
citrus aphid
Unhealthy plants, eg black
peach aphid
INDIRECT DAMAGE.
Produce honeydew, eg most aphids.
Transmit many virus & virus-like
diseases, eg cucumber mosaic virus.
Stunted growth generally.
Insects and allied pests - Hemiptera (bugs, aphids, etc) 145