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Number 11 – July 17, 2017 Honeyvine Milkweed I have always thought of this plant as a weed. Recently I spent some time pull- Honeyvine milkweed (Ampelamus albi- ing new shoots from a bed for about the dus or Cynanchum laeve) is a native, per- third time this summer. It is aggressive ennial vine that spreads by seed and long and persistent and I know it will be spreading roots. The stems are slender, back. Unfortunately, herbicides are not smooth, twining, and without the charac- an option for this particular site. Re- teristic milky sap that is typically present peated hand removal can eventually with other milkweed species. The leaves eliminate it. are dark green, smooth and large, grow- ing up to 6 inches long. They are heart- I have learned, however, that to many shaped on long petioles and opposite on this plant is desirable as it serves as a the stem, which helps to distinguish this food source for the Monarch butterfly. species from similar looking weedy vines Butterfly gardening is quite popular now such as bindweeds. Flowers appear mid- with the decline of the Monarch popula- summer and are long lasting. Flowers tion. I came across one-pint plants are small, whitish or pinkish, sweetly fra- available for sale on eBay. Had I have grant, and borne in clusters – very differ- known this plant was so desirable I ent in appearance than the funnel shaped would have been carefully potting up flowers of bindweed and morningglory those new shoots. Upon telling my hus- vines. The flowers will develop into a 3 to band about my findings and actions, he 6 inch long, smooth, green seed pod that replied with, “and that’s why we’re not is similar to that of common milkweed. rich.” Funny guy. Once dry, it will split along the side and release seeds, each carried in the wind by Although it has its merits, I will continue a large tuft of white hairs. Pods persist to think of honeyvine milkweed as a into winter and can then be spotted easi- weed in the location I have it. Perhaps ly in the landscape when evergreens are in another location it would be fine. the backdrop. The presence of the pod This vine can grow to 20 feet long and I hanging from a vine is a dead giveaway have seen it take over sites with reckless for identifying this weed. This weed can abandon. It cares not for your design be a problem in tree plantings since it can plans and will send up shoots at ran- twine around the plants. It prefers moist, dom. If you elect to plant honeyvine fertile soil and full sun but can grow in a milkweed, choose your location careful- variety of conditions. It is often found in ly. Once you have it, you will continue to fencerows and disturbed sites. Other have it for many years. Seed spread will names for this plant include Bluevine and ensure that! Up to 50 pods can be pro- Sandvine. duced from one plant. Seed pods often aren’t visible until the foliage has lization. Though not usually warranted dropped. They should be removed from or recommended, several fungicides are the area once noticed, to prevent spread. labeled to control oak leaf blister. These Use care when pulling vines with pods products are only effective if applied as down so that the contained seeds are a dormant application to buds and twigs. not accidentally released to the wind For more information on this disease of before making it to your hands. System- oaks, visit our Report on Plant Disease. ic herbicides can be used on actively (Travis Cleveland) growing plants. Carefully read and fol- low all product label directions. (Michelle Wiesbrook) Oak Skeletonizer High infestations of oak skeletonizer are Oak Leaf Blister being reported from southern Illinois and Missouri. This insect is known to Oak leaf blister symptoms are noticeable feed on many species of oak and chest- on many oak trees. This disease is nut and is common in low numbers on caused by the fungal pathogen, Taphrina pin oak and red oak in southern Illinois, caerulescens. Although all oaks are sus- but in this case shingle oak is primarily ceptible, red and black oaks are among affected. the most affected by this foliar disease. White oaks are rarely infected. Oak skeletonizer caterpillars eat through the lower leaf epidermis and consume Symptoms begin as circular, raised spots the mesophyll, leaving the upper epi- on the upper surface of the leaf, as seen dermis intact. Initially, damaged leaves in the pictures. Symptoms continue to appear whitish, but soon the exposed ep- develop become more distinctive, and idermis cells die and turn brown. appear as scattered blister-like, puck- ered, or raised areas on the leaves. The green to yellow slender larvae pu- Symptomatic tissues are often thickened pate on the leaves, forming white, and have light green color which transi- ribbed, slender, silk cocoons about one- tions to reddish-brown as the season eighth inch long. There are two genera- progresses. Severely diseased leaves tions per year. The first generation is may drop prematurely. just ending so another generation will occur within the next few weeks. The pathogen survives over the winter on twigs and between bud scales. Infec- There is a high rate of parasitism in this tion occurs early in the spring during species, so the second generation may cool, moist weather, as the buds start to not be all that noticeable. It is common swell and open. Expanded leaves are not to find parasitic wasp cocoons on leaves susceptible. Damage to trees in Illinois damaged by oak skeletonizer. They are is mostly aesthetic and the disease is one-eighth inch long, smooth, oval, generally not considered to be a signifi- white cocoons with indistinct brown to cant landscape problem. Management black markings. They are more obvious should focus on promoting oak tree vig- than oak skeletonizer cocoons and are or through pruning, watering, and ferti- commonly submitted for identification. Although the damage is obvious, control aphid feeds in the spring on apple, pear, efforts are usually not warranted. Severe hawthorn, and mountainash leaves and damage like this in the spring will likely then moves to elm leaves for the sum- reduce growth this year, but a healthy mer. Woolly elm aphid feeds on elm tree should be able to survive without leaves in spring and then moves to ser- serious health impact. Aesthetic injury is viceberry, where it feeds on the roots for severe for landscape trees, but infesta- the summer. Woolly alder aphid feeds tions are so sporadic and the larvae so on alder and then silver maple. The small, that scouting is difficult and pre- woolly elm bark aphid, beech blight ventative treatments are not warranted. aphid, Prociphilus tessellatus (ash host), If necessary, these insects are suscepti- and P. corrugatans (serviceberry host) ble to insecticides labeled for foliar cat- do not apparently switch hosts. erpillars on oak. (Phil Nixon) These insects are more curiosities than pests. Occasionally, a host will experi- Woolly Aphids ence enough leaf curling and honeydew production to warrant aesthetic control, Adult woolly aphids appear as flying lint, and woolly elm aphid can damage ser- tiny drifting angels, or white fuzzies, viceberry roots. Many insecticides are close to ¼ inch in diameter, which seem effective against them while on leaves, to float through the air. If you try to including many pyrethroids, imidaclo- catch one, you soon realize that it is ca- prid, and insecticidal soap. The woolly pable of powered flight. These aphids elm aphid can be controlled on elm are green to blue and covered with leaves to reduce serviceberry root dam- white waxy strands that stand out from age later. (Phil Nixon) the body. Woolly aphids typically feed on two Cicada Killer hosts during a 1-year period, with most species apparently having to switch Cicada killers are solitary wasps that are hosts. This host-switching occurs in var- about 2 inches long, black with yellow ious species from late June to late July, markings, and have reddish, transparent and these fuzzy female adults are their wings. The females dig ½-inch-diameter means of getting to the other host. Once burrows that extend seven to twenty reaching their summer host, they feed inches into the soil. This results in and give birth to additional wingless mounds of loose soil around the burrow generations of females, producing openings. Annual (dogday) cicadas are winged individuals that fly back to the captured, stung to paralyze them, and other host in the fall to lay eggs. These dragged down into the burrows. Eggs eggs hatch in the spring into females laid on the prey hatch into wasp larvae that give birth to more wingless genera- that eat the paralyzed but still living tions of females, producing the winged prey. Pupation occurs in the burrow females that switch hosts. with adults emerging the next summer. There are several species of woolly Male cicada killers establish aerial terri- aphids in Illinois. The woolly apple tories where the females are located. Because bee, wasp, and ant stings are Cicada killer numbers can be reduced in modified egg-laying devices, males can- sandboxes and sand volleyball courts by not sting. However, they are intimidat- covering them with tarps during the day ing to people entering their territory, by when they are not in use. Wasps and buzzing and hovering around one's bees are primarily day-active insects. head. They may even butt you with their Restricting access during the day causes head as they do this to intimidate other the wasps to go elsewhere.

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