Pests and diseases caused by common weeds

The following list of common weeds highlights the type of damage weeds cause to healthy plants.

Common weed name

Pest or disease hosted by weed

Scientific name of pest or disease

Damage caused to healthy plants

Ragwort

Flea Beetle

Longitarsus flavicornis

Destroys roots

Flea Beetle

Longitarsus jacobaeae

Destroys roots

Crown Boring Moth

Cochylis atricapitana

Bores into root crown

Cinnabar Moth

Tyria jacobaeae

Defoliates plant

Slender thistles

Rust Fungus

Puccinia cardui-pycnocephali

Infects leaves and stems

Spear thistle

Receptacle Weevil strain

Rhinocyllus conicus

Destroys developing seeds

Gall Fly

Urophora stylata

Galls flower heads

Variegated Thistle

Receptacle Weevil strain

Rhinocyllus conicus

Destroys developing seeds

Scotch/Illyrian/ Stemless Thistles

Onopordum Seed Weevil

Larinus latus

Destroys developing seeds

Paterson's Curse

Crown Boring Weevil

Mogulones larvatus

Destroys crowns

Root Boring Weevil

Mogulones geographicus

Destroys roots

Boneseed/Bitou Bush

Bitou Tip Moth

Comostolopsis germana

Feeds on growing tips

Black Boneseed Beetle

Chrysolina progressa

Defoliates plants

Tortoise Beetle

 

Defoliates plants

Horehound

Plume moth

Pterophorus spilodactylus

Defoliates plants

St. John's Wort

Mite

Aculus hyperici

Stunts growth

English Broom

Twig Mining Moth

Leucoptera spartifoliella

Destroys new growth

Common Prickly Pear

Cochyneal

Dactylopius opuntiae

Destroys all aerial parts