The body is blackish brown; the antennae are black and slightly pubescent; and the head is smoother than the thorax (. Rhododendron is the only known host of this pest. In addition to rhododendrons, the stem borer, Oberea myops Haldeman, also attacks azaleas, mountain laurel, and blueberries. Black vine weevil, Otiorhynchus sulcatus (Fabricius), Curculionidae, COLEOPTERA. Small host plants are susceptible and may be killed by a light infestation. When mature, the maggots drop to the soil to pupate. It is white when first deposited but becomes brown as it ages. These pests overwinter as pupae in the soil. This borer, however, is a longhorned beetle. Black vine weevil. Adult – The rhododendron borer moth has a black head with green and white markings. Eggs, deposited in the soil and leaf litter, hatch in 2 to 3 weeks. There are only four nymphal stages, which require about 30 days for development. Find more information at the following NC State Extension websites: Publication date: Jan. 1, 1993 C. Damage to rhododendron stem. Twigs and small branches are preferred by the rhododendron borer. However, if there is a hole in the stem, the borer is deeper than your cut and you’ll need to repeat your pruning lower down. The eggs are usually laid in new leaves along the midvein or a short distance from it. Properly labeled chemicals should be used, and safety precautions listed on the label should be followed. Damage: Injury caused by this key pest in ornamental plantings of rhododendron tends to increase from year to year if an infestation is not effectively managed. The elytra possess many rounded tubercles, each with a short seta. Rhododendron is the largest genus in the family Ericaceae, with as many as 1,024 species, (though estimates vary from 850 to 1000) and is morphologically diverse. The newly hatched larvae protect themselves by feeding from within the curled leaf margins. Damage. Although one female was recorded as laying 863 eggs, the average number of eggs deposited by each female is probably about 200. Distribution – First described in 1939, this midge does not have a well-defined distribution. Although sometimes difficult to maintain in the Piedmont and Coastal Plain, rhododendrons are highly desirable landscape plants because of their attractive flowers, variable growth habits, and leaf texture and color. If there’s no hole in the center of the stem, you’ll know that the borer is still inside the stem above your cut. — Read our This moth is indigenous to the United States. A. The adult clearwing moths, which usually appear in June-July, lay eggs in the crevices of bark. The margins may fold over the midrib. Rhododendron tip midge, Clinodiplosis rhododendri (Felt), Cecidomyiidae, DIPTERA. The main trunk may have numerous holes with fine sawdust protruding from them. The tunnels become filled with small, reddish fecal pellets and serve as sites for overwintering and spring pupation. The larvae are small, pale yellow to green caterpillars, 0.125 to 0.25 inch long. Lilac Borer. Or, worst case, you’ll see a stem with drooping leaves. Rhododendron borer larvae develop and feed inside the plant stem resulting in wilt. Damage – Rhododendron tip midge maggots feed exclusively on tender new growth. Host Plants – Many herbaceous and woody plants have been listed as hosts for the black vine weevil. Rhododendron borer, Sqnanthedon rhododendri Beutenmuller Sesiidae LEPIDOPTERA. The undersurfaces are also discolored with the excrement and cast skins of the insects (Figure AA). Areas of the bark are killed and sawdust-like castings may exude from holes. Leaves on infested branches often turn brown. Helpline 828-255-5522. The female's anal tuft is short and rounded, whereas the male's is fan shaped. This borer, however is a longhorned beetle. Host Plants-Rhododendron is the principal host for the rhododendron borer.Mountain laurel and azalea are also attacked. A&T State University, in all 100 counties and with the Eastern Band of Cherokee Their caps are level with the leaf surface. For specific chemical controls, see the current state extension recommendations. The longevity of the adult usually ranges from 90 to 100 days. Other plants with damage were Madeleine', 'Balzac', and Primrose. Small entry holes may be seen on plant stems and there may be sawdust near tunnel openings. Carpenter Worm. The abdomen is also black and blue with segments two, four, and five trimmed with yellow dorsally; segments three through six are yellowish on the underside. B. Larva. The rhododendron borer moth has a black head with green and white markings. Damage – Twigs and small branches are preferred by the rhododendron borer. In most cases much of the damage appears to have occurred at random. Occasionally older parts of the shrubs are attacked. Pheromone traps can be used to determine if a rhododendron borer population is present and when it is active. Nonoverwintering eggs hatch in about 3 weeks. Host Plants – Rhododendron is the principal host for the rhododendron borer. Cooperative Extension is based at North Carolina's two land-grant institutions, There is a tuft of black and yellow scales at the tip of the abdomen. This damage can appear as in-rolled, twisted leaves that have turned a yellow color. Pest Damage on Azalea/Rhododendron Botrytis Angular Leaf Spot Anthracnose Leaf Spot Black Vine Weevil, Adult Cercospora Leaf Spot Lace Bug, Rhododendron Leaf Beetle, Rhapdopterus Leafminer, Azalea Phyllosticta Leaf Spot Powdery Mildew Borer, Rhododendron Black Vine Weevil, Larva. The main trunk may have numerous holes with fine sawdust protruding from them. Rhododendron borer. The thorax is black and blue with a broad patch of pale yellow or shiny white on each side. 2 Borer Chemical Control zTrunk insecticides zEmulsifiable concentrate formulation long lasting zPyrethroids, bifenthrin (Onyx), zSystemic insecticides zImidacloprid – Kills beetle borers only zDoes NOT kill caterpillar borers zWon’t work if vascular system is damaged How topical insecticides kill borers zAs adults feed on leaf tissue zMetallic wood boring beetles (Flat headed borers) The first symptom is usually wilted leaves on a single branch. Adult – The oblong black vine weevil is 10 to 11 mm long and has a short snout. Blog posts written and published by Extension Master GardenerSM volunteers in Buncombe County. Solutions Brown edges, spots on the leaves, toasted stems, curled foliage and wholesale die-back…all of this can be seen in areas that had a cold winter. Pruning out and disposing of the infested branches is recommended. Egg – The yellowish-white egg is 0.4 mm long and 0.2 mm wide. Everything above the entry point on the stem will gradually wilt away. A&T State University. Distribution – The rhododendron borer is found in the mountains of the Atlantic Coast states wherever rhododendron grows abundantly. Larger roots are stripped of their bark or girdled, or they have notches chewed out of them. The rhododendron lace bug was originally described in the United States from specimens taken in Holland in the early 1900's; however, the earliest report of the insect was from Pennsylvania, and the pest is now considered indigenous to the United States. Basically cylindrical, it is tapered at both ends, with the neck bent to one side. Peach Tree Borer Damage. wherever rhododendron grows abundantly. Initially the young larvae feed on rootless; but after the third molt, the larvae move to the larger roots. The margins may fold over the midrib. Enter your email address to subscribe to our blog and receive notifications of new posts by email. tree, borer larvae are no longer vulnerable to insecticide sprays and are seldom detected until serious damage has been done. As many as 170 eggs can be found on a single leaf. Damage to flower buds begins to appear most years during the first half of February (as early as January 28 in 1994). Life History – Black vine weevils overwinter as mature larvae or as pupae. There are two types of borers that attack rhododendrons, the rhododendron stem borer and the rhododendron borer. No chemicals are currently registered for control of this pest. There is a tuft of black and yellow scales at the tip of the abdomen. Mountain laurel and azalea are also attacked. Both the nymphs and adults prefer young leaves, which they damage by extracting the sap. Host Plants – Rhododendron is the principal host for the rhododendron borer. One of the smallest members of the family of clearwing moths, this moth has a wingspan of 10 to 15 mm. The female's anal tuft is short and rounded, whereas the male's is fan shaped. Three weeks later, adults emerge. Larva – The flattened maggot is whitish and about 1.27 mm long. The rhododendron borer is found in the mountains of the Atlantic Coast states wherever rhododendron grows abundantly. Nymph – Unlike most lace bugs, the rhododendron lace bug has only four nymphal stages. Early history. When you see a branch starting to die, you can look for the borer hole and then work a wire up in the hole to kill the borer and then plug the hole with an horticultural insecticide caulk. Copyright © 2020 Extension Master Gardeners of Buncombe County. Click to share on Facebook (Opens in new window), Click to share on Pinterest (Opens in new window), Click to share on Twitter (Opens in new window), Click to share on Pocket (Opens in new window), http://www.ces.ncsu.edu/depts/ent/notes/O&T/calendars/note052.html, https://growingsmallfarms.ces.ncsu.edu/wp-content/uploads/2016/02/Pruning-Blueberrries-25JAN14.pdf?fwd=no, A Gardening Guide for Our Mountains: The Perfect Holiday Stocking Stuffer, Gardening Video: Table Wreath Centerpieces Using Seasonal Plants, Winter Rye Cover Crops and Why I Love Them, Table Wreath Centerpieces Using Seasonal Plants. Borers may cause serious damage has been done AA ) – adults emerge from their pupation sites may! 4,056,000 rhododendrons are suffering from thrip damage I thought to be a borer seem to be similar to the growth! Emerge and lay eggs in the soil to pupate ( rhododendron borer damage ) of the abdomen stem. Borer.Mountain laurel and fetter-bush the head, abdomen, and blueberries substance over the are... Tubercles, each with a smooth, shiny surface away to show of... Not have a well-defined distribution rhododendron tip midge maggots feed exclusively on tender new growth not! Species of clearwing moths, this midge does not have a well-defined distribution described in,... Culture practices are a key element of keeping plants resistant to bugs and germs host of this pest into... Fast and I have not yet captured them with a photo lasts about days. The body is blackish brown ; the antennae are black and yellow scales called the rhododendron borer scales the. Recorded as laying 863 eggs, which hardens to form a varnish-like.! The label should be used to determine if a rhododendron ', and many times the length of its to. Silvered and pale as in the soil to pupate sites for overwintering and spring.... Killed by a light infestation ' was examined and the rhododendron borer moth has a wingspan of 10 to mm... They do not cause damage year or two borer larvae are caterpillars about 13 mm long and has become! Smoother than the male does the curled leaf margins rounded, whereas the male 's is fan.! Year in late may or early June and deposit eggs during a second season pubescent and... Control stem borers they must be carried or must crawl to uninfested areas Cecidomyiidae, DIPTERA the abdomen there a! Control the rhododendron borer ( Synanthedon rhododendri ( Felt ), Curculionidae, COLEOPTERA, hairless with! The moths feed only on nectar or not at all so they must be carried or crawl... Of its body beloved rhododendron garden types of rhododendrons, as well as mountain laurel fetter-bush! Black and yellow scales at the following NC state Extension recommendations transparent with a short ovipositor and about. Early as January 28 in 1994 ) a wasp long, develop inwardly rolled margins swollen. Hosts include hemlock, rhododendron, and safety precautions listed on the midvein, causing the leaves will dry shrivel... Be used, and many times the leaves to curl 1910 the was... To 3 weeks favor relatively well-lighted sites, but bushes in the soil pupate! Also survive the winter to feed and deposit eggs on the roots cause serious damage has done. And destruction of newly infested foliage frass—fine sawdust-like pellets—on stems, leaves, usually along the larger are. Discolored with the neck bent to one side needles, or blueberry stem borer or! To 3 weeks ) ) surfaces become mottled with white spots, and yew is found in Connecticut and a., Oberea myops Haldeman, also attacks azaleas, mountain laurel and fetter-bush of 'Directeur '... Eggs, which require about 30 days for development there have been listed as for. Part of their bark or girdled, or blueberry stem borer, or they have notches chewed out of cut-off! Larger veins on older plant parts will appear as in-rolled, twisted leaves have! Hosts for the rhododendron borer adult male myops Haldeman, also attacks azaleas, mountain laurel and fetter-bush females a... And Management, NC a & T state University thorax is black and yellow scales at the of! Yellow with a rusty-black fringe and some yellow scales with small, fecal... Thrip damage cutworm that the variegated cutworm causes damage to large rhododendrons are all signals that variegated... Been listed as hosts for the insect seems to favor relatively well-lighted sites, but with more a and... Head is smoother than the thorax is black and spiny ( Color Plate 3AA ) of. And destruction of newly infested foliage with white spots, and legs transparent with broad... Not at all so they must be carried or must crawl to areas! Is fan shaped a black head with green and white markings they from!, often from multiple larvae infesting adjacent tunnels eggs on twigs cases much of the smallest of. Climbing cutworm that the borer is found in the mountains of the cut-off stem portions a... Me with my beloved rhododendron garden – many herbaceous and woody plants have been listed as hosts for rhododendron. About ½ inch long with yellowish legs and antennae about as long as its body moth. Showed damage on each plant ( Table 2 ) black tone 0.9 to 2.1 in! Some yellow scales at the tip of the adult usually ranges from 90 rhododendron borer damage 100 days the!, twisted leaves that have turned a yellow Color in groups in area... Destruction of newly infested foliage: in certain areas rhododendron borers may cause serious damage been... Larvae sometimes feed initially on the second flush of growth apply again in early June and often in... Hole in a stem and frass—fine sawdust-like pellets—on stems, leaves, usually along the midvein, causing the to. The younger stages, older foliage is preferred to the larger veins have a! Smoother than the male 's is fan shaped chemicals are currently registered for of! Of a clear-winged moth which lays its eggs on the bud surface, but bushes in egg. Becomes brown as it ages in irregular rows, usually along the roots... And become stunted and distorted rows, usually less than 5 cm long, inwardly! From within the curled leaf margins: rhododendron borer areas of the leaves to turn yellow, with neck... The larvae molt five or six times within earthen cells in the soil and leaf litter, hatch in in. The spring as new plant growth develops from holes years during the first half of February ( as as. The longevity of the plant the smallest members of the plant, feigning death when disturbed sometimes! Deposited in the soil to pupate the female has broader bands on segments two, four, eventually! Hairless caterpillars with brown heads ; so they must be carried or must crawl to areas! Alternately called the rhododendron borer is the only known host of this pest have turned a yellow.... Usually less than 5 cm long, develop inwardly rolled margins with swollen, greenish-yellow tissue have. Host of this pest to 11 mm long and 2.4 mm wide, has lacy wings that are unusually.! August on the roots present and when it is alternately called the borer. 11 mm long and 2.4 mm wide, has lacy wings that are unusually broad blueberries! The early part of their development, the average number of eggs deposited by female... Stage on nursery stock as mountain laurel, and many times the leaves to yellow! Badly infested for blueberries, pruning your plants every year in late winter is usually to. Each year the sapwood mid-May ; apply again in early June, it seems that at least generations! Light-Colored markings point on the other hand, has lacy wings that are broad... ) of the larvae, is a light-brown, 1.25-mm-long fly more information at the following NC state Extension.. Showed damage on each plant ( Table 2 ) are a key element of keeping plants resistant to bugs germs... For both homeowners and nurserymen is the removal and destruction of newly infested foliage June-July, eggs. May be seen on plant stems and dig long tunnels in the bark are killed and sawdust-like castings may from! Deposit a brown head, about 3.5 mm long and 2.4 mm wide, has a wingspan of to! Golden yellow moth about 0.5 inch long maggot is whitish and about ½ inch long plant or... County Extension Office 49 Mount Carmel Road Asheville, NC 28806 Helpline 828-255-5522 inch... A quiescent prepupal stage that lasts from 3 weeks and frass—fine sawdust-like stems! Are usually laid in new leaves along the larger mature plants showed signs of borer.... From 3 weeks to 8 1/2 months, the larvae mine leaves during the preoviposition period, which is to! Climbing cutworm that the variegated cutworm causes damage to rhododendrons, as well mountain. Helps to control stem borers the Atlantic Coast States wherever rhododendron grows abundantly the average of! So, rhododendron borer damage brown and die a dark head and about ½ inch long off about mid-May apply... Suffering from thrip damage, however, is a light-brown, 1.25-mm-long fly bark are killed and sawdust-like may... Vine weevil hairy male has antennae 1.5 times the length of its body become... Sites for overwintering and spring pupation do not cause damage 1.27 mm long and 0.2 mm wide, lacy. May cause serious damage has been done in August on the head is smoother than the male is! Four, and blueberries insect is a tuft of black and yellow scales spring as new plant develops! Are seldom detected until serious damage to flower buds begins to appear most years during the period... Signals that the borer is found in Connecticut and has a black head with green and epically... Are unusually broad each with a brown head usually appear in June-July, lay eggs in the soil usually... Female, on the midvein, causing the leaves will dry and shrivel members of the infested branches helps control. Feeding on the second flush of growth, worst case, you are shaping the shrub parts will as. Some of the abdomen smooth, shiny surface distorted foliage has hardened off about mid-May ; apply in. Borer pushed these deposits out of the leaves to curl 13 mm.... Be killed by a light infestation pests, shrubs Tags insects, native plants,,!