| Boxwood Psyllids | Yellow Poplar Weevils | Hawthorn Lace Bugs |
| Honeylocust Plant Bugs | San Jose Scale Egg Hatch | Lesser Peachtree Borer - First Flight |
| Eastern Tent Caterpillars | Oystershell Scale Egg Hatch | Lilac/Ash Borer |
| Pine Adelgids | Pine Needle Scale Egg Hatch | Inkberry & Holly Leafminers Emergence |
Pesticide Applicator Training- Maintained by the Entomology department, this site is a continuous source of training information. Dates and locations of approved initial and continuing education meetings for commercial applicators which have been approved by the Division of Pesticides are posted regularly. One listing contains meetings in the state or close by. A second list contains national meetings. This site also provides access to publications and training manuals.
Integrated Pest Management- Maintained by the Entomology department, this page has information on the program in Kentucky along with on line scouting information and fact sheets.
Winston Dunwell, Extension Horticulturist
I originally wrote this in 1995 as a guide to the Daylily Evaluation Program at the UKREC, Princeton. From there I shared the thoughts found below with several daylily groups (Tepal Times Vol. 7(2):2). I see no reason to change the general theme that we all should grow daylilies resistant or at least tolerant of disease and insect pests.My interest in daylilies started a number of years ago as many people in the Kentucky nursery industry had daylily collections (Lee Squires, John Korfhage, Hugo Davis, Mitch Leichhardt, and others). I visited Mitch Leichhardt and Casey and Cindy Schott at Leichhardt's and Casey gave me a few fans to spruce up the entrance to the UKREC. Unfortunately, the crew that planted them threw all the labels away. I went back to Casey and Cindy of Schott Gardens and they gave us several daylily cultivars and we planted them and that started it all. We now have about 125 cultivars and are hoping to add more (and remove some). Our collection is for plant characteristic evaluation. Currently, we evaluate for landscape/garden success, so if "Dragon Lore" one of my favorite dark colored daylilies loses it's bloom color and bleaches out due to thrip damage we don't worry about it, the damage doesn't always happen.
Originally, I assumed there weren’t any serious pests to worry about and I still believe from a landscape gardener aspect there should not be a requirement for extraordinary pest management other than providing a reasonable environment and selecting the appropriate cultivar. The difficulty arises for hybridizers. It is easy for me to say "that cultivar did not survive, the thrips, aphids, or crown rot got it and good riddance", but if a particularly beautiful plant is developed that has a known pest susceptibility is to be maintained as part of the breeding stock some sort of pest control may be required.
Of course, Bill Munson devoted the whole preface of his book, Hemerocallis: The Daylily, 1989, to the presentation of a problem "--daylilies were what I would describe as plain, but consistent, dependable and hardy--- But regrettably it is not as dependable as it once was and is indeed beginning to be fraught with infirmities---" to cure the problem he claims there shouldn't be any susceptibility in any of the breeding lines and we essentially need to work only with strong healthy plants. His final statement in his two page preface states "If we lose our heritage of health and vigor all the beauty that has been achieved will be for naught".
I know of no way to disagree with his discussion. In the Spring 1995 issue of The Daylily Journal (Vol. 50, No.1, p. 81) well known hybridizer Grace Stamille wrote to Lana Ross "Have you tried the use of natural predators to eat your thrips? If you can get a healthy population going of Minute Pirate bug (Orius insidious) or the equivalent in your area, you would not need to spray anymore. They eat aphids and thrips. We also use a predatory mite (Phystoseiulus persimilis) to control spider mite should they come our way. We have not sprayed at all since we've been here in Florida. None of the Convention Gardens use insecticides. We followed Bill Munson's lead of many years ago when he gave up spraying and let the beneficials in the area build up-----."
Are thrips more of a problem for the hybridizer/daylily collector because of pest pressure due to what often becomes a monoculture of daylilies? I would suspect so, but considering the comments of highly respected hybridizers and the fact that the development of a Best Management Plan for the growing of daylilies would probably include natural selection of pest resistant cultivars would indicate that pesticide-free production practices may be the only acceptable way to grow Daylilies in order to ensure continued consumer interest.
by John Hartman, Extension Plant Pathologist
Cankers are localized dead areas of twigs, branches, limbs, trunks, and even roots of woody plants. They are often caused by invasion of bark or cambial tissues by fungi or bacteria which then kill phloem, cambium, and the outermost xylem. The bark in an infected area may shrink, crack, and expose the wood beneath.
Infection occurs through wounds such as mechanical injuries, leaf and fruit scars, branch stubs, and cold-injured or sun-scalded tissues. Many fungi and bacteria that cause cankers normally inhabit the surface of the tree, or possibly exist inside the tree as latent pathogens, and only cause disease when the tree is under stress. However, some fungi and bacteria aggressively attack trees and cause cankers. Cankers not involving pathogenic microbes can also be caused by mechanical injuries such as hail, heat, or cold.
Perennial cankers. Target-spot cankers caused by fungi such as Nectria or Eutypella on hardwoods are roughly circular or elongate with much callus at the canker edges. Wounds and branch stubs are invaded by the fungus during the tree's dormant period. The plant forms callus around the infection site during the growing season, but the fungus invades more tissue the following dormant period. This back-and-forth struggle between the tree and the pathogen creates concentric ridges of callus tissue. Although infection spread is relatively slow and target cankers seldom kill the tree, they do weaken the tree structure and detract from its appearance.
Annual cankers. Weak parasites, such as the fungus Fusarium, normally don't cause disease problems unless the tree is under environmental stress and low in vigor. Infection occurs during the dormant season, but during the growing season host callus tissue walls off the canker and prevents further spread. Although annual cankers do not persist, continued stress makes it likely that more cankers will form and it opens the possibility of invasion by other diseases.
Diffuse cankers. Fungi such as Cytospora, Botryosphaeria, Hypoxylon, Phytophthora, or Cryphonectria (chestnut blight) and bacteria such as Erwinia (fire blight) produce cankers with little callus at the margins. Because the pathogens invade so rapidly, the tree tissue at the canker margin is killed and branches or whole trees are girdled and killed sometimes in one season. Some diffuse cankers are favored when the tree is under stress, but most are not. Canker blights are diffuse cankers in which the disease develops rapidly and kills collateral branch and foliage tissue by way of girdling and canker-rots are diffuse cankers that cause significant internal wood decay.
Canker disease management. Woody plants in the nursery and landscape should be inspected for cankers. Look for a) localized areas of roughened or cracked bark, especially around wounds and branch stubs, b) ridges of callus formation, c) small red, dark brown, or black pimple-like fungal fruiting bodies in the center of or around the edges of the cankers.
Promote tree vigor with mulching, soil aerification, judicious fertilization, and watering so that the tree's natural resistance to disease can be expressed and wound healing can begin promptly and develop rapidly. In the nursery and landscape, a) prune trees and shrubs only during dry weather and not in late summer or fall when canker fungi may be active, b) prune out cankered twigs and branches being careful to avoid damage to the branch collar, c) prevent drought or flooding, d) control weeds and other competitors, but avoid herbicide injury, e) prevent mechanical injury, f) protect trees from defoliating insects and diseases, and g) remove trees weakened by cankers.
by John Hartman, Extension Plant Pathologist
Dutch elm disease, caused by the fungus Ophiostoma ulmi, and its aggressive counterpart Ophiostoma novo-ulmi (sometimes referred to as American elm disease), has eliminated American elm trees from many Kentucky landscapes in past decades. The Lexington Herald-Leader newspaper recently profiled a northern Kentucky nurseryman, Dick Ammon, who is growing disease-resistant American elms. Thus, in Kentucky as well as nation-wide, there is interest in bringing back the American elm. The following material was adapted and summarized from an article from the proceedings of the recent Third International Elm Conference written by Keith Warren of the J. Frank Schmidt & Son Co.
The American elm, because of its tolerance to urban growing conditions and its favorable form was the dominant street tree in the U.S. in the early part of this century. Because Dutch elm disease all but eliminated this tree from the landscape, efforts have been underway for years to find elms to replace them. Nurseries like J. Frank Schmidt & Son (and Dick Ammon and others) have many disease-resistant elms in some stage of production now, with several already available for planting.
The elms of horticultural importance in the U.S. belong to four main groups: Chinese elm (Ulmus parvifolia); other Asian elms (U. pumila, U. japonica, U. wilsoniana); European (U. glabra, U. carpinifolia) and European-Asian hybrids; and American elm U. americana). Some of the cultivars used in the nursery trade that are resistant to Dutch elm disease are discussed below. Consult with horticultural and nursery professionals for more details of these disease-resistant cultivars.
Chinese elm (Ulmus parvifolia) group: Chinese elm, often called lacebark elm, is Dutch elm disease resistant and has desirable horticultural characteristics such as exfoliating bark. But with a size only about half that of American elm, it would be used differently in the landscape.
'Allee' elm has a form similar to American elm, but it is smaller, growing to 50 ft. This cultivar may be one of the most desirable selections, because, along with 'Athena' it combines good hardiness with good bark characteristics.
'Athena' elm grows to about 30 ft. with a rounded head.
'Central Park Splendor' elm grows to about 40 ft. and is perhaps the hardiest of the Chinese elm selections. It will be available in the year 2000.
'Dynasty' elm grows fast, attaining a height of 40ft.
'King's Choice' elm has experienced some branch breakage problems due to its fast growth.
'Drake', 'Sepervirens', 'Ohio', and 'Pathfinder' are also listed as Chinese elm cultivars.
Other Asian elms (U. pumila, U. japonica, U. wilsoniana) group: Unlike the Chinese elm, the Siberian elm (U. pumila) is not a desirable landscape tree. However, in breeding programs, improved selections and hybrids using this and other Asiatic elms have resulted in some very good Dutch elm disease-resistant cultivars.
'Accolade' elm, an U. japonica x U. wilsoniana hybrid comes close to duplicating the American elm form. It grows to a height of 70 ft. and in addition is resistant to elm leaf beetles. It will be available in 2000.
'Danada Charm' elm, to become available in 2000, is similar to Accolade, but perhaps not quite as good.
'Prospector' elm grows to 40 ft. and also resists leaf beetle. It is an U. wilsoniana selection.
'Discovery' elm is a very hardy U. japonica selection.
'Vanguard' elm is heat and drought tolerant. This tough tree is a complex hybrid of Asiatic elms and grows to a height of 45 ft. It will be available in 2000.
'Triumph' elm is a cross between 'Vanguard' and
'Accolade' growing to a height of 55 ft. It is attractive both as a young and a mature tree. It will be available in 2000.
'Sapporo Autumn Gold', 'New Horizon', and 'Cathedral' elms, hybrids between U. pumila and U. japonica, are available in the trade. 'Jacan' is another disease-resistant U. japonica selection.
European (U. glabra, U. carpinifolia) and European-Asian hybrids group: European elm breeding programs produced several Dutch elm disease resistant selections that have been hybridized with Asiatic types to produce many of the hybrids in use today as American elm replacements.
'Pioneer' elm is a hybrid between the two European elms and grows quickly to a height of 50 ft.
'Homestead' elm is a complex Asiatic and European hybrid that develops a good street tree form to a height of 55 ft.
'Frontier' elm has a good vase shape and burgundy-red fall color. This U. carpinifolia x U. parvifolia hybrid grows to 40 ft.
'Commendation' elm is a complex hybrid growing into an upright form to about 60 ft. It will be available in 2000.
'Patriot' elm is a complex hybrid that will be available in 2001. It grows to 50 ft and has an upright vase shape.
Other complex hybrids in this group include 'Regal', 'Urban', and 'Vegata' elms.
American elm (U. americana) group: There is great interest in and demand for American elms with resistant to Dutch elm disease. Unlike their Asiatic counterparts, American elms are still susceptible to elm yellows disease, and of course all elms are susceptible to some canker diseases and other problems. Nevertheless, resistance to Dutch elm disease is the important feature driving the release of these new elms. Look for these cultivars.
'Valley Forge' elm has the best disease tolerance of the American elms and will grow to 70 ft with the typical vase-shaped form. It will be available in 2001.
'New Harmony' elm has the second best disease tolerance and may have a somewhat better form than 'Valley Forge', also reaching a height of 70 ft. It is also expected to be available in 2001.
'Jefferson' elm is a national park service selection that has not been widely tested. It is expected to reach a height of 50 ft. and will be available in 2002.
'Washington' has a similar history to 'Jefferson' and also has not been widely tested.
'Princeton' is an older cultivar with good disease resistance and good horticultural characteristics.
Other disease resistant American elms include 'Independence' and the "American Liberty" group. The latter are seedling selections and may vary in their form and disease resistance.
Although we may have to wait a few years for some of the new disease-resistant elms, several are available now. Now is a good time to plan to introduce some of them into our landscapes and along our streets, at least on a trial basis. American elm was the best of the urban street trees. Let's hope that they can make a comeback.
Taken from Iowa State University web site
Julius Sterling Morton, the father of Arbor Day, said, "Other holidays repose upon the past; Arbor Day proposes for the future." These words, said 121 years ago, reflect the necessity of tree planting today.
The first Arbor Day took place on April 10, 1872, in the neighboring state of Nebraska. J. S. Morton, an early conservationist, believed trees could serve as windbreaks, hold moisture in the soil, and provide lumber for this prairie state.
He began planting trees and urged others to do so as well. After Morton joined the state board of agriculture, he used the opportunity to propose a specific day to be set aside for tree planting. The idea took off and on that day in Nebraska 1 million trees were planted. Just two years later it was made an annual event and in 1885 the Nebraska state legislature passed an act specifying April 22 (Morton's birthday) as the legal holiday Arbor Day. In the first 16 years, 350 million trees were planted in Nebraska. Another contributor to tree planting was Birdsley Grant Northrup. He organized village improvement associations and advocated landscape beautification through tree planting. Towns in Connecticut, New York, and Massachusetts owe their beauty to the efforts of this man.
In April 1882, the American Forestry Congress and the American Forestry Association met in Cincinnati, Ohio. The superintendent of Cincinnati schools and Arbor Day supporter, John B. Peaslee closed the schools for the occasion and had the children participate in the state's first Arbor Day. In 1883 the American Forestry Congress adopted a resolution calling for the annual observance of Arbor Day in all schools throughout the country. Two years later a similar resolution was adopted by the National Education Association. In the early years state and federal governments offered incentives such as free seeds and plants or cash for tree planting. This practice was considered unfair to the nursery industry and was abandoned although many nurseries still provide free trees.
The most widespread observance of Arbor Day is in the public schools where trees are planted and pageants are held, as well as other events. Students are introduced to the beauty of trees and taught of their importance for shade and as wildlife sanctuaries. They are taught the various uses of lumber for construction, paper, and other vital products. Other individuals and groups, state and local governments, and civic organizations support Arbor Day. Although it is celebrated in all 50 states, it has never been made a federal holiday. Each state designates its own date for the celebration. Attempts to set a uniform date of observance have failed mainly due to differing climatic conditions. However, April 23 has been designated as National Arbor Day. Many states have designated the last Friday in April as Arbor Day and legislative efforts to designate this as National Arbor Day continue.
In Iowa, the first Arbor Day was held on April 20, 1874; sponsored by the Iowa State Horticultural Society. A committee consisting of Judge C. E. Whiting, D. W. Adams, and Prof. H. H. McAfee put together a list of premium trees and set the date of April 20, 1874, as the date the trees had to be planted to be eligible for the prizes awarded for those entering the tree planting contest. Many people planned to plant trees that day. However, Mother Nature had her own ideas and decided to cover the state with snow and rain. The rules of the contest were amended and the trees were planted before the end of April. The tree planting contest continued for 23 years. The Iowa legislature set the last Friday in April as Arbor Day in Iowa. The Iowa Horticultural Society, Plant Iowa, and many other groups continue to promote Arbor Day. The Iowa State Horticultural Society, the Department of Agriculture, and the Nurserymen's Association have set a fall planting day in Iowa of September 24, 1993.
The artist Grant Wood captured the true spirit of Arbor Day in his canvas "Arbor Day" where teacher and children labor to beautify an Iowa country schoolyard. Martin Luther declared, "If I knew that tomorrow the world would go to pieces, I would still plant my tree." Walter Irving expressed a similar feeling when he wrote: "He who plants a tree cannot expect to sit in its shade, or enjoy its shelter; but he exults in the idea that the acorn shall grow to benefit mankind long after he is gone." With these closing words, enjoy Iowa's Arbor Day on Friday, April 30, and the fall planting day in September.
by John Hartman, Extension Plant Pathologist
Rhododedrons are grown in landscapes throughout the world and are often considered aristocrats of the garden. Their growing requirements dictate that they be grown in moist, but not wet, acid soil; screened from the hot sun; and sheltered from cold, cutting winds. Unfortunately, gardeners growing rhododendrons in Kentucky face real challenges in trying to keep them alive and healthy. Based on plant disease diagnostic laboratory records, most of the rhododendron disease problems are either environmental stresses or diseases that are active on plants growing under stressful conditions. The following are some of the infectious Rhododendron diseases we see here.
Botryosphaeria Dieback-Dieback and canker, caused by the fungus Botrysphaeria dothidea, is often found on individual rhododendron branches. The first indication of a problem usually is the appearance of individual stems with drooping leaves that are rolled inward. Closer examination of affected stems reveals a reddish-brown to black sunken canker that girdles the stem. Cankers develop slowly and may appear a month or two after infection of a pruning wound, an injury, or a leaf scar.
This disease is more likely to occur on plants suffering from heat and drought strees or winter injury. Pruning tools have been implicated in spread of the fungal spores, so pruning out dying stems should be done carefully with clean clippers, sanitized between each cut. There are no disease-resistant cultivars, and effective fungicide sprays for Botryosphaeria dieback are not available.
Phytophthora Dieback-This disease appears infrequently in Kentucky, but is sometimes confused with Botryosphaeria dieback. The Phytophthora fungi that invade the twigs and stems also invade the leaf petioles and leaves. The brown leaf lesions are unique for this disease. The fungus Phomopsis, causing a similar dieback, is also found occasionally.
Phytophthora Root and Crown Rot-Phytophthora cinnamomi, P. cactorum, P. citricola, and other species sometimes cause rhododendrons to decline and die in Kentucky landscapes. Examination below ground will reveal a reddish-brown color of decayed roots, and a reddish-brown discoloration of the stem at or just below the soil line. Phytophthora root rots are favored by wet soils. Periodic flooding provides opportunities for the fungus to produce swimming spores which function in disease spread. This disease attacks plants growing in otherwise good growing conditions.
Flooding episodes should be avoided by providing good drainage, and gardeners need to be careful not to introduce the fungus into the planting on diseased plants. Soil drench fungicides are available for disease suppression, if needed. Root rot resistant cultivars have been identified, but in poorly drained circumstances, even these cultivars may succumb to disease. In recent years, the fungus Rhizoctonia has appeared on declining rhododendrons examined in the plant disease diagnostic laboratory. This fungus apparently attacks plants growing in stressful circumstances.
Gray Blight-Leaf blight, caused by Pestalotia spp. appears as gray lesions with brown margins. As the lesions expand and cover the leaf, defoliation may result. Dark pimple-like pycnidia of the fungus may appear embeddded in the diseased leaf tissue. The gray blight fungi are regarded as weak parasites, invading leaf tissues that have been injured by sunscald or winter cold.
Powdery Mildew-Powdery mildew disease is easily recognized by the white, powdery signs of the causal fungus, Microsphaera penicillata, and possibly other species, on the surface of the infected leaves. Young plants are most vulnerable to the disease, especially those grown in the shade. This fungus also attacks several other landscape plants such as birch, dogwood, honeysuckle, lilac, maple, and oak, which can serve as sources of fungal inoculum. Chemical control is not normally needed, but is easily achieved by applying fungicides according to label directions.
As can be seen from this list, if adverse growing conditions don’t directly cause decline, they favor many of the diseases commonly found on rhododendrons.
From North Carolina State University web site
The boxwood leafminer is the most commonly reported pest of boxwoods in North Carolina. Accidentally introduced from Europe, this small fly seems to prefer American boxwood, although English and Japanese boxwoods are also susceptible.
Boxwoods infested with this leafminer develop blisters on the lower leaf surface. Infested leaves are usually smaller, off-color and drop sooner than healthy leaves. Heavily infested boxwoods usually have sparse foliage and poor color.
Adult leafminer flies emerge over a two-week period in early spring after the boxwoods have put out their growth. These flies are like tiny, orange mosquitoes (about 1/8 inch long) which swarm around or cling to boxwoods. After laying eggs in the leaf tissue, the flies die. There is one generation per year.
Tiny, whitish maggots hatch and feed inside the leaf. As they grow (up to 1/8 inch long), the maggots become bright yellow. Several maggots may develop in a single leaf. Their feeding induces the formation of blisters on the lower leaf surface inside of which the maggots develop for about a year. Very early the next spring, the blisters form a thin, translucent spot called the window, and the maggots develop into pupae. Fully developed pupae wriggle through the windows and hang down. Soon adult flies emerge from the pupae to begin a new generation.
Control
Apply a labeled pesticide just as the boxwood leafminer flies appear in the spring. The flies emerge just after the new growth appears on boxwoods in April.
From Virginia Tech Cooperative Extension web site
Psyllids are green, sucking insects which as adults look like miniature cicadas or large leafhoppers. They are also called jumping plant lice since their specialized hind legs enable them to spring into the air to take flight. Plants injured by boxwood psyllids show conspicuous cupping of the foliage. The damage does not seriously impair the health of the plant unless severe infestations persist over a period of years.
The boxwood psyllid overwinters as a nymph within the egg shell. Eggs are inserted between the bud scales by adults during July and early August. Embryonic development takes place between then and fall. The nymphs emerge in mid-to-late April as soon as the buds begin to open. They feed on the new tender growth causing shoots and leaves to become deformed. Nymphs are green and produce white, waxy secretions. They remain clustered within cupped leaves until early June when adults first mature. One generation occurs each year.
American boxwood is the prime host. Severe infestation over a period of years causes serious damage. Occasionally English boxwood plants exhibit cupped foliage of a psyllid infestation but damage is rarely severe.
Effective control of psyllids can be achieved but some cupping of foliage will occur since nymphs begin feeding on new growth immediately after emergence. Control measures should be applied as soon as new growth appears. Sprays later will kill the insects, but with little or no reduction in leaf cupping. A wetting agent or a spreader-sticker must be added to achieve good control.