Insect Management Handbook

Athrips rancidella

Pest description and damage The cotoneaster webworm is a dark brown caterpillar, 0.25 to 0.5 inch in length. It typically webs leaves together and feeds within tubes snaking along the branches. Besides unsightly webbing, larvae skeletonize leaves. Death of branches can occur. The webworm is primarily a problem on Cotoneaster horizontalis (rock cotoneaster) and only in some years.

Includes

Apple aphid (Aphis pomi)
Potato aphid (Macrosiphum euphorbiae)

Anisandrus (Xyleborus) dispar

Oedemasia salicis

Forest tent caterpillar (Malacosoma disstria)
Western tent caterpillar (Malacosoma californica)

European red mite (Panonychus ulmi)
Twospotted spider mite (Tetranychus urticae)

Scolytus rugulosus

Pest description and damage The adult shothole borer is a brownish-black beetle about 0.08 inch in length. The larvae are white, legless, and about 0.16 inch long. When the numerous beetles emerge, the bark takes on a shothole appearance. These beetles are primarily a problem on injured or stressed plants, but healthy trees growing adjacent to blocks of neglected trees are attacked.

Comstockaspis (Quadraspidiotus) perniciosus

Includes Edwardsiana rosae

California pear sawfly (Pristiphora abbreviata)
Pear slug (Caliroa cerasi)