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Pearslug sawfly - Caliroa cerasi

Description

Adults are small, stout, shiny black wasps about 1/3" long that emerge in late June or early July. Eggs are inserted one by one in circular slits on the upper surfaces of leaves and hatch about 2 weeks later. Larvae are shiny, slimy, swollen at the head end, and range in color from olive green to orangeish-green. Full grown larvae leave plants to pupate in the soil and may emerge as adults in about 2 more weeks to produce a 2nd generation. Some remain dormant until the following spring.

Damage

Larvae skeletonize the upper surfaces of leaves. Heavily damaged leaves may brown and drop early. Infestations, even heavy ones, generally have little impact on plant health, although the damage may be unsightly.

Cultural Controls

Spray leaves with a forceful jet of water to dislodge the larvae.

Chemical Controls

Acephate

Signal Word: Caution
Pesticide Class: Organophosphate

Azadirachtin

Signal Word: Caution
Pesticide Class:

Bifenthrin

Signal Word: Caution
Pesticide Class: Synthetic pyrethroid

Carbaryl

Signal Word: Caution
Pesticide Class: Carbamate

Chlorpyrifos

Signal Word: Danger
Pesticide Class: Organophosphate

Cyfluthrin

Signal Word: Caution
Pesticide Class: Synthetic pyrethroid

Deltamethrin

Signal Word: Caution
Pesticide Class: Synthetic pyrethroid

Diflubenzuron

Signal Word: Caution
Pesticide Class: Insect growth regulator

Imidacloprid

Signal Word: Caution
Pesticide Class: Neonicotinoid

Imidacloprid+Bifenthrin

Signal Word: Caution
Pesticide Class: Neonicotinoid, Synthetic pyrethroid

Imidacloprid+Clothianidin

Signal Word: Caution
Pesticide Class: Neonicotinoid

Insecticidal soap

Signal Word: Caution
Pesticide Class: Insecticidal soap

Lambda-Cyhalothrin

Signal Word: Caution
Pesticide Class: Synthetic pyrethroid

Permethrin

Signal Word: Caution
Pesticide Class: Synthetic pyrethroid

Pyrethrins

Signal Word: Caution
Pesticide Class: Botanical

Spinosad

Signal Word: Caution
Pesticide Class: Microbial

Ultra-fine oil

Signal Word: Caution
Pesticide Class: Horticultural oil

Locations Affected

leaves

Plant Environment

outdoors

Scouting Season:

July - Mid , July - Late , August - Early , August - Mid , August - Late , September - Early , September - Mid , September - Late

Plants Affected

• Amelanchier - Serviceberry
• Cotoneaster - Cotoneaster
• Crataegus - Hawthorn

Photos

Pearslug sawfly larvae and typical 'windowpaning' feeding damage

Pearslug sawfly adult

Pearslug sawfly eggs