IMPORTANT AND COMMON INSECTS AFFECTING ROOTS

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Coleoptera

Bark Beetles

(Coleoptera: Scolytidae) 

  *These beetles are often vectors of disease organisms, e.g. black stain root disease.
Hylastes nigrinus Hosts: Conifers Damage:Adults feed on fine roots of large, dead trees, and on roots of small weakened trees, occasionally killing trees through girdling. Eggs are laid on roots. 

 

Hylurgops porosus Hosts: Conifers Damage: Common throughout the west. Breeds in lower bole and root collar. 
Hylurgops subcostulatus Hosts: Conifers Damage: Attacks pines throughout the west. Some species called "sour sap beetles", due to their habit of breeding under the bark of wet, fermenting conifers, e.g. roots or tree boles in contact with the ground. 

 

Fir root beetle,

Pseudohylesinus granulatus

Hosts: Abies spp. Damage: Breeds in lower bole and root collar of Abies spp. Can cause mortality when it occurs with P. sericeus. Often associated with Armillaria ostoyae

 

Weevils (Coleoptera: Curculionidae)

*Warren's root collar weevil,

Hylobius warreni 

 

Hosts: Pine and spruce Damage: Occurs throughout Canada. Very common around Prince George. Larvae feed at the root collar and on roots on pines and spruce, causing characteristic black, crusty pitch masses in the soil. When scraped these turn white. Mortality is rare, but importance may increase with increased plantations. Possibly associated with root disease, e.g., tomentosus root disease. Adults are flightless. A similar species, Hylobius pinicola, is less common, and has well developed hind wings, and a more northern distribution in the west. Other species of Hylobius (particularly H. congener and H. pales) are important pests of regenerating conifers in eastern and central North America. 

 

Pissodes schwarzi Hosts: Pine and spruce  Damage: Throughout the west. Breeds in root collar and roots of weakened immature pine and spruce. Very similar in appearance to P. terminalis

 

*Strawberry root weevil, 

Otiorhynchus ovatus,

Rough strawberry root weevil, 

O. rugosostriatus

Black vine weevil,

O. sulcatus

Hosts: Hardwoods, conifers and ornamental plants Damage: Flightless, parthenogenetic weevils with short snouts. The larvae of all three species are damaging in nurseries, but also in horticultural and agricultural crops. Larvae feed initially on fine roots, and later on larger roots and the root collar. 

See also Seedling Insects


 

June beetles (Coleoptera: Scarabaeidae)

*Tenlined June beetle,

Polyphylla decemlineata

Hosts: Conifers Damage: The larvae, known as white grubs, can cause extensive damage to young plants. Can be particularly numerous in grassy areas. The larvae of other scarab beetles may also damage roots of seedlings. 

See also Seedling Insects

Homoptera   These insects have sucking mouth parts. They feed by sucking the juices from plant cells

 
 
Cicadas 

(many species)

Hosts: Conifers Damage: Nymphs feed on roots of plants. 
Root aphids (many species) Hosts: Conifers or hardwoods Damage: All life stages feed on roots.