PLANT PROTECTION 1 – Pests, Diseases and Weeds

PLANT PROTECTION 1 – Pests, Diseases and Weeds
PLANT
DAMAGE
Honeydew
LIST OF SOME
SPECIES
TRUE BUGS.
Acacia-spotting bug
sucking damage to leaves
Green
vegetable bug
DIRECT SUCKING DAMAGE.
Damage is caused by both the nymphs and adults sucking plant sap.
LEAVES Chlorotic mottling, eg azalea lace bug, leafhoppers,
greenhouse whitefly
Death of tissue, eg black peach aphid, green peach aphid
Distortion, curling, eg cabbage aphid, cherry aphid, green peach
aphid, grape phylloxera aphid
Galls, eg purse gall aphid
Premature leaf fall, eg lerp insects
FLOWERS Distortion, eg aphids
FRUIT Distortion, eg apple dimpling bug
BUDS Mottling, eg green vegetable bug
Premature fruit fall, eg bronze orange bug
SHOOTS Death, eg black peach aphid, crusader bug
STEMS Distortion, eg green peach aphid, black citrus aphid
Galls, eg woolly aphid
Wilting, eg crusader bug, longtailed mealybug
ROOTS Distortion, galls, eg grape phylloxera aphid, woolly aphid
INDIRECT DAMAGE.
Presence of insects, nymph skins and excreta may reduce value of the crop
and affect trade, eg scale on fruit.
Transmission of many virus and virus-like diseases especially by
aphids, some leafhoppers and whiteflies.
Tainting of fruit, eg green vegetable bug, shield bugs generally.
Honeydew/Sooty mould. Many Hemiptera, eg aphids, leafhoppers, lerp,
mealy-bugs, soft scales and whitefly consume large quantities of watery plant sap.
– Many sugars present in plant sap are not required by insects and are excreted as honeydew.
Wherever honeydew falls sooty mould may grow.
– Some Hemiptera, eg psyllids allow their honeydew to harden into protective ‘lerps’ while
others use it to attract ants which protect them against predators.
– Relationship can be specific, eg a single ant species may attend a single Hemipterous
species or it may be broad.
– Reduces the value of affected plants and fruit. Plants can look unsightly.
COMMON NAME SCIENTIFIC NAME HOST RANGE
(not exhaustive)
BUGS (several families)
MIRID BUGS Family Miridae
Acacia spotting bug
Apple dimpling bug
Rayieria tumidiceps
Campylomma livida
STINK BUGS
Family Pentatomidae
142 Insects and allied pests - Hemiptera (bugs, aphids, etc)
Acacia
Apple, also peaches, potato, etc,
May prey on some insects
Bronze orange bug Musgraveia sulciventris Citrus (Family Tessaratomidae, very
closely related to the Pentatomidae)
Spined citrus bug Biprorulus bibax
Citrus, esp. lemons, mandarins
Green vegetable bug Nezara viridula Wide range of plants, especially
fruit parts and pods
Horehound bug Agonoscelis rutila Horehound, ornamentals,
occasional fruit trees
JEWEL BUGS
Family Scutellidae
Cotton harlequin bug Tectocoris diophthalmus Cotton, related weeds,
kurrajongs, bottle trees
CHINCH BUGS
Family Lygaeidae
A large number of true
Rutherglen bug Nysius vinitor Fruit, vegetables, weeds
bugs feed on seeds and
fruit; some are predators SQUASH BUGS Family Coreidae
and some feed on fungi
Crusader bug Mictis profana Ornamentals, eg rose, eucalypt,
wattle, fruit, eg citrus, grape
Fruitspotting bug Amblypelta nitida Developing fruits
Do not confuse cicadas
with grasshoppers or
beetles that have
chewing mouthparts
STAINER BUGS
Family Pyrrhocoridae
Harlequin bug Dindymus versicolor Ornamentals, fruit, vegetables
Pale cotton stainer Dysdercus sidae Cotton, native/cultivated plants
MISCELLANEOUS BUGS
weeds
Azalea lace bug
Spittle bugs
Stephanitis pyrioides
Aphrophoridae,
Cercopidae
Azalea, rhododendron
Ornamentals, eg wattles,
eucalypts; herbs, eg mint
CICADAS. CICADAS (Family Cicadidae) More than 250 species in Australia
Greengrocer Cyclochila australasiae Nymphs of cicadas live in the soil
Double drummer. Thopha saccata
for up to 17 years feeding on tree
roots. Large numbers are noisy