PLANT PROTECTION 1 – Pests, Diseases and Weeds

Ruth rescan
PLANT PROTECTION 1 – Pests, Diseases and Weeds
BEETLES AND WEEVILS
Summary - Some exceptions
SOME DISTINCTIVE FEATURES
BEETLES ADULT Flight Usually can fly
Head
Body
LARVA Legs
Antennae
Not long
Not roughened
Various (not
usually elbowed)
Mostly thoracic
legs which may be
short or long
PLANT DAMAGE
.DIRECT FEEDING DAMAGE.
LEAVES
FLOWERS
BUDS
FRUIT
SEED
STEMS
BARK
Eaten, eg Christmas beetles
Leafmining, eg lantana
leafminer
Skeletonization, eg leafeating
ladybirds
Chewing damage, eg orchid
beetle
Chewing damage, eg
driedfruit beetles
Bark, eg elm bark beetle
Borers, eg longicorn beetle
.INDIRECT DAMAGE.
Transmit diseases, eg elm bark beetle
spreads Dutch elm disease overseas
WEEVILS ADULT Flight Many unable to
fly
Head
Body
Antennae
Long snout
Usually rounded,
often roughened
with knobs,
spines, scales
Often elbowed,
clubbed at tips
.DIRECT FEEDING DAMAGE.
LEAVES
SEEDS
STEMS
BARK
ROOTS
TUBERS
Chewed edges, eg black vine
weevils
Chewing, eg rice weevil
Bark, eg pine bark weevil
Borers, eg elephant weevil
larvae
Surface chewers, eg garden
weevil
Gouging tubers, eg black vine
weevil
LARVA Legs
Body
Legless
Stout grub,
usually feeds
within plant
tissues (stems,
trunks, roots,
seeds etc)
.INDIRECT DAMAGE.
Fig. 68. Elephant weevil (Orthorhinus cylindrirostris.).
Left: Exit holes made by emergence of adults after pupating
under bark. Right: Adult elephant weevils, note elbowed
antennae. PhotosNSW Dept of Industry and Investment.
102 Insects and allied pests - Coleoptera (beetles, weevils)