(800) 262-3804, Iowa State University | PoliciesState & National Extension Partners, By Laura Jesse, ISU Plant and Insect Diagnostic Clinic, Like us at Plant and Insect Diagnostic Clinic, Like us at Department of Plant Pathology and Microbiology. Small, wet areas on the bark, dead branches, adventitious growth (water sprouts on trunk and large branches), or sloughing and cracking of bark can all be symptoms of dogwood borer attack. There is one generation each year and immatures overwinter on the twigs. Infected leaves exhibit marginal leaf scorch, dead patches, reddish discoloration, yellowing and premature defoliation. The adult beetle emerges from infested twigs in the spring and the female lays her eggs in healthy twigs. They may roll up the leaves or spin webs. The sawfly has been in existence since the Triassic period of the Mesozoic era. There are two distinctive black dots just behind the head. This scale is usually controlled by beneficial insects and generally does not require spraying. There are several scale insects, such as calico scale, cottony maple scale, and oystershell scale, that can become pests on dogwood. Dogwood Borer Damage at the Base of Flowering Dogwood. Sawflies can be controlled through the use of insecticides, natural predators and parasites, or mechanical methods. Sawfly larvae look like caterpillars and feed on leaves like caterpillars, but sawflies are wasps. Also, when larvae are one-half full grown or larger they will do little more feeding. The first evidence of the presence of the clubgall midge may be a wilted, deformed leaf. The dogwood sawfly and sawflies in general can cause considerable defoliation because often they feed in groups. Adults emerge from dogwood trees around mid-May and continue throughout most of the summer. Apply according to the label instructions. Adding Pyrethrin creates the organic equivalent of a one-two knockdown punch. But it's the worm-like larva that causes damage to plants. Photo: Terry S. Price, Georgia Forestry Commission, Bugwood.org. Just trying to understand them. Dogwood Borer (Synanthedon scitula) Adult. Insecticides labeled for sawfly control on the plant in question will also work if treatment is applied when larva are young. Sawflies are one of the few insects in the wasp family that feed on plants. There is only one generation each year, with the larva overwintering inside the twig. Some larvae look like caterpillars with three pairs of large legs and seven pairs of smaller false legs. They move onto the bark to overwinter. Unfortunately we often notice the damage after the larvae are done feeding, so it is important to look for the larva before treating. After the second molt, the larvae become covered with a white powdery material. Just a few sawfly larvae on a large or mature plant may do little damage and can be tolerated. There is one generation each year. Sawfly larvae have chewing mouthparts that leave holes in the leaves. Get some gloves and go over your rose petal leaves. As the slugs grow, they become lighter colored. When fully mature, pear sawfly larvae resemble green-orange caterpillars. 2150 Beardshear Hall There is one generation each year. On the other hand, those from the Pergidae family are pests in oak, eucalyptus, and hickory. There are three species of Macrempytus (Hymenoptera: Tenthredinidae) sawflies in the eastern United States. Upon hatching, the young caterpillar finds a suitable place to enter the tree such as a wound, scar, woody gall, or branch crotch. This is one of the easiest methods to get rid of them (though it is kinda gross). Get it Monday, Sep 14. I have a lot of the fly stage out in my yard--at least I think they are the sawfly fly stage. 1. After their final molt, they lose the powdery covering and change color. Photo: John A. Davidson, University of Maryland, Bugwood.org. Photo: Terry S. Price, Georgia Forestry Commission, Bugwood.org, The dogwood twig borer is a less serious pest of dogwood. If you catch the infestation when the caterpillars are small they can easily be removed by hand. Different species of sawflies feed on different plants. There may be one or two generations a year. By Mary Kay Malinoski, Principal Agent, University of Maryland Extension. Photo: David Laughlin, Horticultural Student, Bugwood.org. The larvae (young insects) resemble caterpillars and feed on the foliage of several species of dogwood and are most commonly seen on shrub dogwoods [e.g., silky dogwood (Cornus amomum), redosier dogwood (C. sericea)]. Each was once surrounded by a leaf. REC, Lower Eastern Shore Kousa dogwood (C. kousa) and hybrids of kousa and native dogwood (C. florida) are resistant to anthracnose and decline and should be used to replace dying trees. The larvae bore into the tree and feed in the phloem (tissues that move plant foods produced by leaves) and outer sapwood. Small dogwood sawfly larvae hatched from nearby eggs. These mature larvae will wander about in search of an overwintering site, generally in soft or decaying wood. Dogwood sawfly Macremphytus tarsatus Order Hymenoptera, Family Tenthredinidae; common sawflies Native pest Host plants: Dogwood, particularly gray and redosier Description: Adult sawflies are wasplike. Or look for pupal cases on or near the plant and destroy them. 4.5 out of 5 stars 226. The eggs hatch into the caterpillar-like larvae that feed on the leaves. Unfortunately we often notice the damage after the larvae are done feeding, so it is important to look for the larva before treating. Notice those twigs branching off the main stem? And, by the time you realize you have a sawfly infestation, it’s too late. But each dogwood leaf can have dozens of sawfly caterpillars grasping onto the undersides of leaves … every leaf. The dogwood sawfly, Macremphytus sp., is an interesting sawfly because the second larval instar (stage in the larval development between molts) is covered in a white waxy covering and the last larval instar is yellow and black. As they grow and molt, they become covered with a white waxy coating. Those that belong to the Argidae family are common in birch, oak, elm, and rose bushes. Infested twigs should be clipped off several inches below the girdled or infested portion and destroyed. They do not settle on the leaves but stay to feed on the twigs and branches. The adult is a day-flying clearwing moth. Sawfly management usually involves the use of chemical sprays. Some leave holes or notches in the leaves, while others skeletonize the leaves by completely devouring the tissue between the veins. After the second molt, larvae become covered in a white powdery sub-stance. When the sawflies are larger, one of the contact or systemic insecticides registered for control … Examine the undersides of leaves for the flat, yellow, immature scales along the leaf veins. Dogwood sawfly (Macremphytus tarsatus), Newark DE, September 2017.Second picture is from a previous post. Sawflies feeding mid- to late summer also do less harm to a plant. They are large (1/4 inch long), black and white-spotted and swollen. They will be found where honeydew and/or sooty mold (a fungus that grows on honeydew) are present. The adult is an elongate (5/8 inch long) beetle with long antennae. These immature scales turn yellow and feed on the leaves during the summer. Photo: James Solomon, USDA Forest Service, Bugwood.org. This helps reduce the amount of pesticide used. Treat sawfly larvae when they are young and half their full-grown size or less when pesticides are more effective. That’s over 250 million years ago! Dogwoods planted too deeply, inadequately watered during the first two years of establishment and drought periods, or physically wounded at the trunk (e.g., mower damage), are more susceptible to pest infestations. Sawfly larvae are easily dispatched using repeated applications of a horticultural oil or insecticidal soap. Management is seldom needed, but if desired, wear gloves and manually remove and discard the larvae. During the dormant season (when leaves have fallen from deciduous trees) apply a horticultural oil (4% dormant rate) to control overwintering immature scales. The cottony maple scale is easiest to find in May and June. The dogwood borer is the major pest of dogwood. There are two distinctive black dots just behind the head. There may be one or two generations a year. The adult (1/5 inch long) is a black and yellow, 4-winged non-stinging wasp (sawfly) that is rarely noticed. Dogwood sawfly larvae in different larval instars. Large trees are seriously injured from dieback of branches and loss of large patches of bark over mined areas on the trunk. Repeat applications might be needed as the product needs to come in contact with the sawflies. Sawflies first appeared 250 million years ago in the Triassic. The flatheaded appletree borer attacks a wide variety of shade and fruit trees. Photo: James Solomon, USDA Forest Service, Bugwood.org. The adult midges emerge in May and the female deposits eggs in new terminal leaves. Larger trees with ongoing infestations often develop rough, knotty areas on the trunk and large branches, and may lack vigor. Cottony Maple Scale (Pulvinaria innumerabilis). The adult beetle is 1/2 inch long, oval, flattened, greenish bronze above and brassy below. Sawfly larvae are easily knocked off plants, and can be dropped into soapy water to finish them off. Copyright © 2020ISU Extension and Outreach We have several common sawflies in Iowa that are bothersome to gardeners; the pearslug whose larvae feed on the leaves of a variety of fruit trees, the roseslug on roses, the scarlet oak sawfly that feeds on oak, the willow sawfly, and the European pine sawfly. However, further defoliation can be halted by knocking the larvae onto the ground to stomp them or into a bucket of soapy water to drown them. Azadirachtin and spinosad are effective for one or two weeks so sawflies that feed on treated foliage are still affected. They are found on twigs and branches. Links to this article are strongly encouraged, and this article may be republished without further permission if published as written and if credit is given to the author, Horticulture and Home Pest News, and Iowa State University Extension and Outreach. kurstaki (Btk) is a co… Young larvae (1/2 inch long) are greenish-black, elongated, slim and slug-like, with very little evidence of legs. Leaf and flower blight Irregular, brown, wrinkled patches form on flower bracts and leaves in the spring. Crawlers are present in May. Some of the most common pest causes of a dogwood tree dropping leaves are: Borer insects; Scale; Dogwood sawfly; Insect pests are usually the easiest to diagnose. It most frequently attacks trees that are stressed or injured. It is essential that young trees receive adequate water during establishment. Sawfly eggs hatch into larvae which go through eight stages of growth. Sign in to suggest organism ID. The adult is an elongate (5/8 inch long) beetle with long antennae. By mid-June, they die, shrivel, and turn brown. This insect usually does not cause serious problems. Oysershell Scale (Lepidosaphes ulmi). So how do you kill sawfly larvae naturally, without pesticides? Conifer sawflies, for instance, are found in coniferous trees, such as pine and spruce. If problems occur year after year, scout early for eggs or larva. If this article is to be used in any other manner, permission from the author is required. Calico Scale (Eulecanium cerasorum), females. Dogwood sawfly, Macremphytus tarsatus, has been found on shrubby dogwood species on campus.While this pest looks like a caterpillar, it is actually the larval stage of a wasp-like … Be sure the specific host is listed on the insecticide … kurstaki (Btk) is a common low impact insecticide used against moth and butterfly caterpillars. 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