Key Features
- Membranous windows on leaves
- Leaf missing between leaf veins
- Small green larvae under leaves
Symptoms
Rose sawflies chew and scrape rose leaves between leaf veins as larvae. Heavy infestations can be unsightly and result in leaf drop.
Biology
Several species of sawflies feed on roses as larvae. Although they superficially resemble caterpillars adults are stingless wasps, not moths or butterflies. The bristly roseslug sawfly is the most commonly encountered with up to six generations per year. The European roseslug sawfly has one generation a year and is somewhat slimy to the touch. It has one generation per year. The curly slug sawfly has two generations. All rose sawflies winter as pupae near the soil surface. Adults of all species begin their activity in late spring or early summer.
Management Recommendations
Look for small membrane covered holes on leaves in mid spring soon after roses leaf out. Apply insecticides before extensive defoliation occurs. Be sure there are live larvae present before you treat. Treatment of the first generation of sawflies may reduce later season injury when reproducing sawflies come back to the same plants to lay eggs later in the season. Spinosad will kill sawflies without causing an outbreak of spider mites later in the season.
Effective Pesticides
Active Ingredients include: Acetamiprid, Azadirachtin, Bifenthrin, Carbaryl, Horticultural oil (Paraffinic or superior oil) , Insecticidal soap (Potassium salt of fatty acid), Malathion, Neem oil, Spinosad
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