Rose slugworms are the larvae of a sawfly. Apply pesticides only when larvae are actually present, before infestations reach critical levels. The larvae can be knocked from the leaves with a strong water spray; once dislodged they will not be able to get back to the rose bush. Mon – Fri | 9am – 5pm, Join the RHS today and support our charity. They are pale yellowish-green with light brown heads. Bug Clear Ultra) is also available. Coat the plant and ground thoroughly. The key is to find larvae while they are still small and before damage becomes severe. They are about 1/2" long and yellow-green with yellow heads. Not effective: Bacillus thuringiensis (Bt), a commonly used biological insecticide that offers control of many caterpillars, is NOT effective against sawfly larvae. Bristly roseslug larvae are about 5/8" long and greenish white with long, stout bristles. RHS Garden Hyde Hall Spring and Orchid Show, Free entry to RHS members at selected
For light infestations, remove the infested leaves and destroy the larvae. They are both the larval stage of flying insects known as sawflies. Repeat spraying are needed, every seven days, but do inspect daily and remove any lingering larva. If this is not sufficient to reduce the damage to acceptable levels then you may choose to use pesticides. When spraying, be sure to spray both sides of the leaf and the ground below the plant as the larvae pupate in the soil prior to overwintering. Although the larvae damage is unsightly, it doesn’t kill the plants. Larvae that are discovered while they are still small can be effectively controlled with any rose insecticide spray or dust. The Garden wouldn't be the Garden without our Members, Donors and Volunteers. This damage may also be called “window-paning.”. Larvae appear several weeks later, feed on soft leaf tissue for about a month, and then drop into the soil to pupate. the RHS today and get 12 months for the price of 9. A third species, the curled roseslug sawfly (Allantus cinctus) generally produces two generations per year. instructions on preserving and mailing insects. The key is to find larvae while they are still small and before damage becomes severe. Copyright © 2020ISU Extension and Outreach
Within this group the shorter persistence pesticides (that are usually certified for organic growing) are likely to be less damaging to non-target wildlife than those with longer persistence and/or systemic action. REC, Lower Eastern Shore
If you live outside of Iowa please do not submit a sample without contacting the Plant & Insect Diagnostic Clinic. 1. Crop Rotation, Succession & Companion Planting, Lily-of-the-Valley Shrub, Pieris japonica. For an organic approach to Strategy 2, control other insects using strictly organic methods. (800) 262-3804, Iowa State University | PoliciesState & National Extension Partners, Like us at Plant and Insect Diagnostic Clinic, Like us at Department of Plant Pathology and Microbiology. For an organic approach to Strategy 3, consult the Organic Materials Review Institute (OMRI™) for appropriate insecticidal soap and Neem products. Organic Materials Review Institute (OMRI™), Rose slug, a sawfly larva (Hymenoptera), on underside of rose (, Rose slug (Hymenoptera), a type of sawfly larva, and damage on underside of rose leaf (, The rose slug is a sawfly larva not a caterpillar and cannot be controlled with, Rose slug (Hymenoptera), a type of sawfly larva, and typical skeletonized damage on upper leaf surface of rose(, Adult pear sawfly / pear slug (Hymenoptera) found on a rose leaf (, Rose slug, a sawfly larva (Hymenoptera), and feeding damage on upper leaf surface of rose (. They curl up like a cutworm and are about 3/4" when mature. Early detection can often result in simple cultural control measures. Use an Insecticide. Pesticides for gardeners (pdf document outlining pesticides available to home gardeners), Join
You can also use neem oil or manual removal. To control heavy infestations, use horticultural oil or spray with spinosad. Check roses in May and June (in Maryland) for the slug-like, greenish-yellow larvae on the under surface of skeletonized leaves. Light infestations of rose slugworm can be tolerated as the damage to a few leaves will not affect the vigour of plants. The Royal Horticultural Society is the UK’s leading gardening charity. The roseslug is a sawfly larva (plant-feeding wasp). The grazing activities of the slug-like larvae of the rose slugworm sawfly can cause leaves on roses to turn brown and dry up. Be sure to aim the water at both upper and undersides of leaves. Early detection can often result in simple cultural control measures. 222879/SC038262, Where possible tolerate populations of rose slugworm, Encourage predators and other natural enemies of sawfly in the garden, such as, Check plants regularly from June for the presence of larvae and remove by hand where practical, If numbers of larvae are too high for hand picking, control may be achieved by spraying with pesticides. In general, light to moderate infestations are cosmetic in nature and rarely harm the host plant. 2. Start inspecting the underside of rose leaves in mid-April. Ames, IA 50011-2031
Strategy 1 is a strictly organic approach. Pesticides containing neem or spinosad are effective, as … They secrete a slimy substance over their body surface that makes them resemble small slugs. The second generation in July and August can be the most damaging. Bristly roseslugs may have as many as six generations each year. The larvae do not make holes in the leaves but graze away the leaf surface until only the epidermis remains. You can also use with soap and water, neem oil or horticultural oil. Mature larvae look like caterpillars, but they are not. Inspect both upper and lower surfaces of the leaves. Their bodies are translucent and the gut contents can often be seen as a dark green line inside the body. They are velvety, yellow-green in color and up to 1/2 inch long. Control Light infestations of rose slugworm can be tolerated as the damage to a few leaves will not affect the vigour of plants. As they mature they go through numerous larval states until they fall to the ground. Westland Resolva Bug Killer), deltamethrin (e.g. If the infestation is light, pick off and destroy the larvae. The females are shiny black with yellowish-orange markings on the body. Or attract natural predators for natural sawfly control. Continue checking plants throughout the growing season. Start inspecting your rose plants about mid … They have a tapered shape and slimy appearance that gives them a vague resemblance to a true slug. Management of rose sawfies . Begin looking for sawfly larvae in mid-spring (rose sawflies) or early summer (pear sawflies). Contact information for each states diagnostic laboratory for U.S. residents. Sawfly larvae have jointed legs and a bead-like head. Heavier attacks, however, can weaken plants when leaf loss stresses them to the point of vulnerability to other insect and disease attacks. Because the veins of the leaf are left intact the damage is called skeletonization (that is, the “skeleton” of the leaf remains). If the infestation is light, pick off and destroy the larvae. Rose sawfly: Adult sawflies emerge in early spring and lay their eggs on the underside of host plant leaves. The larvae grow to a length of about 10mm and are somewhat club-shaped with the head end being swollen. If you detect rose slug problems early on, you can often get rid of the pests using simple nonchemical control measures. Bristly roseslug larvae are about 5/8" long and greenish white with long, stout bristles (left) - They skeletonize leaves by feeding from the undersides of the leaves and later chew holes through the leaves (right), Coiled roseslug Roseslug damage on bud.