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Volume VI1, Issue III OFFICE OF STATE ENTOMOLOGIST June 2003 Pests susceptible to control- based on degree day forecasts ( )=Degree day ranges

• Bagworms (700-800)

• Birch leaf miner (500-1000)

• Bronze birch borer (500-1000)

• Euonymus scale several overlapping generations (500-2100) Bronze birch borer-note • European elm scale (900-1200) Yellow poplar characteristic D-shaped Yellow poplar leafminer larvae inside leaf leafminer damage Calico scales • European pine shoot moth (900- exit holes 1000)

• Flat headed apple tree borer (500- 1700)

• Fletcher scale (900-1200)

• Japanese emergence (900- 1200)

• Lecanium scale (900-1200)

• Lilac borer (900-1200)

• Taxus mealybug repeat applications necessary (700-2100) Adult lilac borer. Use pheromone Lilac borer Pupal skin of a peachtree borer traps to monitor for this . protruding from trunk • Peach tree borer (500-2100) 2-4 sprays during this periond peach and pear trees. This damage can easily • Round headed apple tree borer (500- 2004-The Return 1700) 3 applications at 3 wk intervals results in "flagging," or destroy the current year's of the 17 Year breaking of peripheral twigs growth so increased pruning • San Jose scale (500-2900) repeat on small trees or shrubs. is required to get rid of applications necessary Cicada Orchard and nursery owners damaged areas. The most • Two spotted spider mite (900-2100) probably should not plant serious consequence for • Wooly apple (800-900) Next year brood X of the 17 year cicada will emerge state wide. The young trees or shrubs in the nursery plantings will be the following is an excerpt from an UK years preceding an emer- injury to usable living Entfact 446 about . Inside this issue: gence of periodical cicadas, branches which provide the Damage because young trees may be basic structure for the plant. Oak Moth Caterpillar Pg 2 There are two aspects of peri- harmed by severe flagging. These wounds cause a weak Attacking White Oaks odical cicada damage. The Young trees may be fatally point so branches that are harmed by severe flagging. gathered together and tied Galls Appearing Pg 2 most obvious occurs as fe- males lay their eggs in small More mature trees and during harvest and shipment Seasonal Appearance of Pg 3 branches. A second, delayed shrubs usually survive even are broken very easily. In Ornamental Pests effect can occur as the dense emergences of cica- order to have quality trees to Yellow Poplar Weevil Pg 3 nymphs feed on sap that they das and continue to grow harvest in a production remove from the roots during during subsequent years. nursery, one may have to Dead Branches in Trees Pg 4 their long life below ground. This can be difficult to be- remove 1 to 2 years of Calico Scale Pg 4 Egg laying injury occurs lieve in the month or so fol- growth in order to develop Tree Leaf Spots Often Pg 5 when female cicadas slit the lowing a large emergence usable branches on a fin- Begin in Spring bark on pencil-sized twigs because many deciduous ished product. This may and lay their eggs inside the trees will turn brown due to mean that the trees near the Clover Mites Pg 6 wounds. They prefer grape- breakage and death of pe- end of their production cy- vines and oak, hickory, apple, ripheral twigs. cle may be rendered useless Degree Day Totals Pg 6 PAGE 2 INSPECTOR FINDINGS VOLUME VI1, ISSUE III as a marketable crop during the fall af- stay on for the next four to six weeks or massive outbreaks, damage will poten- ter emergence or during the next year. until egg laying is complete. tially occur even with daily applica- Below ground feeding by large num- can be used to reduce dam- tions. Continued cicada flight to land- bers of nymphs can cause age by cicadas but several scapes and nurseries from surrounding long-term damage. Once applications may be woods keeps reinfestation pressure they have burrowed into needed. Dursban high for several weeks. Control is most the ground and reached the (chlorpyrifos) and Sevin effective when the are hit di- roots, no control method is (carbaryl) are labeled spe- rectly with spray droplets. Residual available. During the first cifically for periodical ci- control must rely on cicadas sitting on five years, feeding by the 17 year cicada cada control. Several syn- treated surfaces long enough to absorb nymphs probably will not thetic insecti- the . This can delay or re- be noticeable. However for years 6 to cides are labeled for landscape trees duce action on the insect. 13 of the life cycle, cicada nymphs may and shrubs. Often, these insecticides The following are some of the products be extremely destructive to plants, es- have a repellent effect that causes in- available to homeowners: Lawn and pecially those that bear fruit. In gen- sects to leave treated surfaces shortly Garden Insect Killer (cyfluthrin) and eral, cicada damage will not be of any after landing on them. The following Ortho Bug B Gone Spray importance on fully-grown shade trees, examples do not list the periodical ci- (esfenvalerate). Spectracide Bug Stop although the current year's growth may cada but are broad spectrum products Multipurpose Insect Control Concen- be reduced. that are effective against a wide range trate and Total Control Outdoor Control of insects - Astro (), Decath- Formula contain (permethrin). Be sure Because egg laying is the real danger lon 20 WP or Tempo (cyfluthrin), to read the product label closely be- from these insects, consider emergence DeltaGard T&O (deltamethrin), and cause many of these products are not as the signal to begin protecting plants. Scimitar (lambda cyhalothrin). Several labeled for fruiting plants and trees that A week or so after emergence, females of these are available only to commer- are bearing. are ready to lay eggs. Plants can be pro- cial applicators. A third alternative is to prune out egg- tected in three ways: covering, spraying Nurseries under a routine spray sched- laying wounds before eggs hatch, espe- and pruning. ule should be sprayed according to in- cially in fruit orchards where juveniles Small trees can be covered with a pro- tensity of the outbreak, which can feeding on roots may decrease fruit tective netting cheesecloth. Be sure to range from a few cicadas in some areas production. Although this is a time- secure the bottom around the trunk to to massive numbers in other areas. Dur- consuming process, it may be a viable prevent the insects from crawling up ing low level outbreaks application alternative considering the production from below. This covering will have to may be needed twice a week. During life and long-term value of fruit trees.

Oak Moth Caterpillar Attacking White Oaks can be severely or completely defoli- Lee Townsend, Extension Entomologist, University of Kentucky ated. While a single defoliation should not adversely affect established, White oaks in several locations in the lines. Many are about 1-1/4 inches long healthy trees, previous droughts or state are being fed upon heavily by the now so they are nearly full-grown and other stresses can increase the impact common oak moth caterpillar. This cat- will stop feeding soon. There is only of this damage. In general, an insecti- erpillar wears camouflage on its back one generation each year with the cat- cide application is neither practical nor and moves like an inchworm. The body erpillars active from May to June. recommended, cultural measures to is brown with tan to black blotches on Common oak caterpillars seem to be promote tree health are more likely to its sides; its back is checkered with dia- able to feed on many kinds of oaks but be beneficial. mond-shaped markings and slanted prefer white oaks. In many cases, trees

Galls Appearing gall tissue. Galls also provide some leaf galls occurs around "bud break" or Lee Townsend, Extension Entomologist protection from natural enemies and as new leaves begin to unfold in the insecticide sprays. Important details of spring. Oaks are susceptible to many Galls are irregular plant growths, which the life cycles of many gall-makers are gall makers. The woolly fold gall, are stimulated by the reaction between not known so specific recommenda- caused by a small fly, is a striking ex- plant hormones and powerful growth tions to time control measures most ample. A fuzzy white pubescence ap- regulating chemicals that can be pro- effectively are not available. Gall mak- pears on the leaf and is associated with duced by some insects or mites. Galls ers must attack at a particular time in a pouch that contains the larval stage of may occur on leaves, bark, flowers, the year to be successful. Otherwise, the fly. Galled leaves are deformed but buds, acorns, or roots. Leaf and twig they may not be able to stimulate the overall tree health is not affected ad- galls are most noticeable. The inhabi- plant to produce the tissue, which versely. More information on galls are tant gains its nutrients from the inner forms the gall. Generally, initiation of available through the extension office. VOLUME VI1, ISSUE III INSPECTOR FINDINGS PAGE 3 Seasonal Appearance of Ornamental Pests and Normal Time Frame to Apply Control Measures (for the month of June) From The University of Tennessee Agricultural Extension Service PB 1589, Frank Hale, University of Tennessee Hosts Pests Walnut fall webworm Shade trees bagworms, leafhop June (early) Yew (taxus) black vine weevil pers

Arborvitae arborvitae leafminer, June (mid) Shrubs Japanese beetle bagworms, black Spruce spruce spider mite, Arborvitae arborvitae leafminer, vine weevil, Fletcher spruce needle miner bagworms, black vine weevil, Fletcher scale Walnut walnut caterpillar scale Ash elm spanworm Willow bagworm Azalea oystershell scale Azalea azalea bark scale, Yew (taxus) Fletcher scale, black Bald-cypress bagworms vine weevil black vine weevil Birch birch leafminer, Birch bronze birch borer June (late) bronze birch borer Flwr fruit trees flatheaded apple tree Buckthorn bagworms Arborvitae bagworms borer, woolly apple Cedars bagworms Euonymus bagworms aphid Cotoneaster San Jose scale, black Fir bagworms Hemlock strawberry root wee vine weevil Flwr fruit trees flatheaded borer, San vil Fir bagworms, black Jose scale, lesser peach Hickory elm spanworm vine weevil tree borer (peach, Juniper juniper tip midge, Flwr fruit trees San Jose scale, bag plum, apricot), bag juniper scale worms, peach tree worms Linden webworms borer Hemlock bagworms Maple flatheaded apple tree Hemlock spruce spider mite, Honeylocust mimosa webworm borer, lecanium scale bagworms, black Juniper bagworms Oak oak skeletonizers, vine weevil Linden bagworms May/June , Horbean bagworms Locust locust leafminer flatheaded apple tree Ivy Japanese beetle Maple flatheaded borer, cot borer, lecanium scale, Juniper bagworms, juniper tony maple scale, bag elm spanworm scale worms Pine European pine shoot Larch bagworms Mimosa mimosa webworm moth, Nantucket pine Linden linden leaf beetles, Oak flatheaded apple tree tip moth Japanese beetle, bag borer, bagworms Rhododendron azalea bark scale, worms, lecanium Pine bagworms, pine tor black vine weevil scale toise scale Spruce spruce needle miner, Oak bagworms Silver maple cottony maple scale, spruce spider mite Pine pine tortoise scale, bagworms Sweet gum sweet gum pit- bag worms Spruce spruce bud scale making scale Rhododendron black vine weevil Yew (taxus) black vine weevil Sycamore Sycamore lace bug

overall health. the buds or feeding on the lower sur- Yellow Poplar Weevil Lee Townsend, Extension Entomologist face of the leaves. Biology

Yellow poplar weevils, also known as There is one generation Mating and egg laying occurs in sassafras or magnolia weevils, are of this insect each year. May and early June. The eggs small black snout beetles that damage Adults pass the winter are placed in the midrib on the yellow poplar, sassafras, and magnolia. in leaf litter. They be- underside of the leaves. This Adults chew distinctive holes in the come active and start to injury can break the leaf midrib. leaves that resemble curved rice grains feed on warm days in Newly-hatched larvae move in size and shape. The larval stage, a late April and early Yellow poplar weevil from the midrib into the leaf white legless grub, develops and feeds May. Before bud where they feed as leaf miners. inside the leaves of poplar and sassa- break, the weevils attack the swelling The mined portion of the leaf turns fras. The combined activity of adults buds leaving their distinctive feeding brown and takes on a scorched appear- and larvae can cause significant leaf marks. As the leaves unfold and ance. When ready to pupate, the larvae loss. While injured leaves cause the enlarge, they, too, are fed upon. Holes move to an inflated portion of the mine trees to be unsightly, damage to estab- in the leaves, about 1/8" in diameter, and spin a spherical silk cocoon. Dura- lished trees probably does not affect its result from adult weevils puncturing tion of the different life stages varies PAGE 4 INSPECTOR FINDINGS VOLUME VI1, ISSUE III with environmental conditions. by the newly emerged weevils can be to the foliage. Treat when feeding dam-

New adults begin to emerge from leaves severe. Leaf drop occurs when damaged age is seen on about 10% of the branches during the second week of June and feed trees are also under drought stress. By and repeat as necessary. Weevils arrive at on the foliage. Sometimes they chew mid-July the adults have disappeared to trees over an extended period; treating at through the leaves, but more often they their hiding places in leaf litter and will the very first sign of damage may be pre- remain inactive until spring. mature and require an additional applica- remove only the lower epidermis and mesophyl, leaving the upper epidermis Control tion in a few days. While the damage may be unsightly, the injury to large, es- intact. This produces many chlorotic Insecticides such as acephate (Orthene), spots and results in the scorched appear- tablished trees in landscapes or wooded carbaryl (Sevin), or chlorpyrifos areas probably will not harm the tree. ance of severely attacked trees. Feeding (Dursban) may be used to reduce damage Dead Branches in Trees ter. It can be assumed that some liquids growth that the plant will be unable to within xylem tissues were frozen prior to support as the evapo-transpiration rate Bill Fountain, Extension Horticulture Specialist the ice storm. As branches were bent by increases in summer and rainfall becomes limited. The best recommendation is to There are many trees in the central Blue- wind and downward by the weight of ice irrigate as necessary to insure that water grass with branches that are slow to leaf as it accumulated on branch surfaces, ice does not become a limiting factor for out or appear to be dead. While we are crystals within the xylem broke rupturing these conductive tubes. As the tempera- trees and shrubs. slightly behind on degree-day accumula- tions, it is not enough to account for this tures rose and fell again, liquids refroze Insects and diseases are opportunistic, delay in shoot growth. The central Blue- in the downward bent branches. As sur- attacking plants that are stressed and less grass experienced a devastating ice storm face ice on branches began to melt, capable of producing defensive chemicals on 15 February 2003. It is my feeling branches assumed a more upright posi- and compartmentalizing damaged tissues. that this meteorological event is the most tion rupturing additional xylem Protective sprays should be used espe- likely cause for branch death and abnor- (conductive) tissues. Add in the destruc- cially for such as dogwood, red- mally late leaf out. tion to xylem tissue resulting from the bud, ash and red maple that are especially sheer act of bending and the tree is left susceptible to borers and other destruc- The ice storm resulted in accumulations with an extensively damaged network of tive pests. Anticipating potential insect of 1.5 inches of ice, sometimes more on xylem tissue unable to move liquids up- and disease problems is the foundation of exposed twigs and branches. If we as- ward from the root system to the buds. plant health care (integrated pest manage- sume that this 1.5 inch diameter is all ment) systems and is greatly superior to water, it amounts to almost 10.5 ounces As the ice melted the still living twigs attempting to solve these problems after of weight per linear foot of twig. When and buds become upright only to die later as the plant was unable to transport water they become acute. this is multiplied by hundreds of feet of twigs on every large branch, it is no won- and mineral elements past the points of Extreme weather events make us realize der that these large structural branches damage. Many of these branches are that no matter how advanced we think we bent and often broke under the ice load. now dead and can not be expected to pro- are, we are all at the mercy of our envi- duce new leaves. Removal by pruning is ronment. Practicing sound management The temperature was cold prior to the the only beneficial treatment. procedures in our urban landscapes will onset of freezing rain and remained at or help to insure that we live in a safe, below freezing for several days. Nor- As we progress into the hot, dry summer healthy, beautiful environment. Losses mally this is not a significant problem months we can expect leaf scorch and from wind and ice are not a total loss if and the freeze-thaw cycle occurs hun- additional twig death on severely dam- we use these opportunities to learn and dreds of times throughout a normal win- aged trees. Fertilization is not the an- swer. Spring fertilization may result in correct our past mistakes.

tion to other trees nearby. & Garden Multi Insect Killer). Decent Calico Scale control of crawlers can also be achieved Mike Potter & Dan Potter, Univ of Kentucky It is too late to impact the mature fe- males, which will soon be dying off. with 2% horticultural oil or insecticidal Mature calico scales are large, black and Monitor the status of egg hatch and soap. Thorough coverage of infested white globular-looking insects about the crawler emergence by flicking off the twigs, branches and adjoining leaves is size of a pencil eraser. They have a soft, adult scales and observing the eggs, important, and since the hatching period leathery body and when crushed ooze a which look like a mass of fine flour. The often lasts about a month, a second appli- gummy, wax-like fluid. The adult female yellowish, newly-hatched crawlers are cation probably should be made 2 to 3 is the life stage now being observed at- weeks after the first. tiny but their movement will be visible to tached primarily to twigs and stems. the naked eye. Calico scales overwinter on the bark as Underneath each female, however, are Insecticide applications timed with emer- mid-sized nymphs. To further reduce the literally thousands of eggs which soon likelihood of problems occurring next will be hatching into crawlers. The gence of young crawlers, will break the cycle of development. Insecticides la- year, it probably would be wise to follow crawler stage prefers to suck plant juices up with a dormant oil application (in fall from the leaves and also excretes large beled for crawler control include Durs- ban, Malathion, Orthene, Talstar, Scimi- or winter) to trees that were heavily in- amounts of honeydew. Crawlers can be- fested with calico scales this year. come wind borne, spreading the infesta- tar, and Tempo(= Bayer Advanced Lawn VOLUME VI1, ISSUE III INSPECTOR FINDINGS PAGE 5 Tree Leaf Spots Often toms are being seen now on sycamores, spot of poplar and many of the anthrac- for example. nose diseases, also cause cankers on the Begin in Spring ---Phyllosticta and other fungi cause twigs, and pruning out cankered wood is John Hartman, Extension Plant Pathologist needed to reduce inoculum. leaf spots with dark margins and tan The most obvious and visible diseases centers. On maple, dark fungal ---Manage the growing environment. of trees are those affecting the leaves. pycnidia can often be seen in these Avoid sprinkler irrigation which wets the spots. foliage. Thin out crowded branches and The effect of each leaf spot disease on tree health varies with the disease and ---Bacterial spot of ornamental Prunus prune away overhanging vegetation from tree affected. In general, those leaf species may cause shot hole symptoms nearby trees to improve ventilation and sunlight penetration. spots that result in premature defolia- which develop in leaves when the dead tion will cause the most harm to the tissue of the leaf spot drops out. ---Provide good growing conditions for tree, and those that appear late in the Cherry leaf spot, caused by a fungus, trees in the landscape. Some leaf spot season or that cause very little death of also causes shot hole symptoms. diseases such as Actinopelte leaf spot of leaf tissue will only slightly harm the oak attack trees under stress. ---Tar spots appear as smooth, thick tree. Thus, it is important to diagnose black tar-like fungal stromata dropped ---When available, use disease resistant leaf spots correctly and to know how a on the leaf surface. cultivars. There are many excellent culti- particular tree is going to respond to the vars of flowering crabapple that are resis- disease. ---Spots caused by rust fungi often tant to scab. have a rusty orange color provided by Symptoms. Leaf spots are usually the masses of spores produced in the Control - chemical. If the tree is a valu- thought of as well-defined lesions or infected spot. Hawthorns and crabap- able specimen and despite the use of dead areas on leaves or needles. They ples will be showing rust spot symp- good cultural practices the leaf spot dis- may be circular or angular on broad- toms within a few weeks here. ease continues to be detrimental to the leaves, or band-like on needles. Be- ---Cristulariella leaf spots usually ap- health of the tree, fungicide sprays cause there are so many different fungi pear as zonate concentric circles on the should be considered. Professional land- and bacteria that cause leaf spots, and leaf, often with black fungal structures scapers have access to a wider range of there are so many different ways that effective chemicals than do homeowners. in the same arrangement. tree species and cultivars react to the ---Use protectant fungicides such as Cap- diseases, the symptoms will vary con- ---Powdery mildew often begins as a small spot with visible signs of the fun- tan, Chipco 26019, Daconil 2787, fixed siderably. copper, Fore, Manzate, Syllit, and Ziram gus on the leaf surface. The initial powdery spots often expand and cover to control a wide range of leaf spot dis- ---Scab disease spots are somewhat cir- eases. the whole leaf. cular, superficial and sometimes rough- ened lesions. Flowering crabapple scab Cause. Many fungi, most of them as- ---Use systemic fungicides such as Ban- spots are visible now on susceptible comycetes or imperfect fungi, are para- ner Maxx, Bayleton, Benomyl, Cleary's crabapples in Kentucky. Crabapple sites of tree leaves and cause spots. 3336, Eagle, Immunox, or Rubigan to target certain specific diseases. leaves often respond by turning yellow Fungi such as Ascochyta, Cercospora, and falling from the tree. Cylindrosporium, Elsinoe, Marssonina, ---Fungicide mixtures may include active

---Conifer needle spots often appear as Microsphaera, Mycosphaerella, Phyl- ingredients with both protectant and sys- yellow or brown bands on the needle. losticta, Rhytisma, Septoria, Taphrina, temic activity which may be advanta- and Venturia can each cause leaf spot geous. Infected needles usually fall from the branch. diseases of several different trees. Leaf ---Bacterial leaf spot diseases are more spot symptoms may also be caused by ---Leaf blisters are swollen or raised difficult to manage, but fixed copper powdery mildews, and rust fungi. Bac- chemicals such as Kocide, Champion, or blister-like spots on the leaf surface. teria such as Pseudomonas and Xantho- Oak leaf blisters may become dead but Bordeaux mixture are most often used. monas also cause leaf spots. Determin- they rarely cause much harm to the ing the exact pathogen causing the the Choose fungicides and bactericides that tree. have the tree and the disease listed on the leaf spot by microscopy or special ---Anthracnose leaf spots tend to spread laboratory tests is sometimes necessary label. The timing of sprays for leaf spots into surrounding tissues so it may be to develop effective control strategies. is critical, and applications often will need repeating. referred to as a blotch. These spots- Control - biological and cultural. turned-blotches finally may progress to extensive dead areas that involve the ---Use sanitation to reduce pathogen It is almost always better to control the whole leaf and shoot. Anthracnose can levels. For the vast majority of leaf disease early rather than later in the sea- also cause shoot dieback because the spot diseases, raking up and destroying son. Be sure that the spray equipment causal fungus can attack small twigs or thoroughly composting diseased that is being used thoroughly covers all and branches. Such anthracnose symp- leaves is sufficient for control. Some surfaces of the foliage. of the leaf spot fungi, e.g., Septoria leaf Clover Mites lent, well-fertilized grass. They do not as crushing them often creates an unde- cause any apparent harm to turfgrass. sirable and durable brown stain. House- Donald Lewis, Ext. Entomologist, IA State Univ. In some situations it may be practical to hold insecticide sprays containing pyre- Clover mites are very tiny arachnids reduce migration of clover mites into thrins can be used for short-term, con- that live and reproduce outdoors, but tact control of wandering mites. the house by removing the turfgrass are frequently encountered as a house- and leaving a bare strip 18-24 inches Degree Day Totals through May 27, 2003 hold pest in early summer and in the wide next to the foundation. This tech- Bardstown—796 fall when they migrate into dwellings nique is not always successful, as the Bowling Green—921 by mistake. They are only 1/64th inch Covington—666 clover mites may migrate over wood Henderson—837 long, soft, oval, and flattened from top chip and rock mulches and through Huntington WV—774 to bottom. They vary in color from flower beds. Lexington—744 rusty brown to dark red. A distinguish- The traditional control for clover mites London—788 ing characteristic is the very long pair is to apply an insecticide spray as a Louisville—788 of front legs that extend forward like Mayfield—828 chemical barrier around the house. Paducah—904 antennae as the mites crawl. Spray the bottom of the foundation, the Princeton—919

Clover mites are harmless. They cannot crevice between the foundation and the Quicksand—865 ground and the lawn for a distance of 6 Somerset—889 bite or sting; they do not infest stored foods; they cannot attack the house to 10 feet out from the foundation. Suc- Degree Day Totals through May 25, 2002 Bardstown - 726 structure and furnishings. They are an cessful chemical control requires a very thorough treatment. Materials labeled Bowling Green - 814 annoyance and nuisance because of Covington - 527 their presence and tremendous num- for this use include , Isotox, Henderson - 763 bers. Clover mites reproduce outdoors. kelthane, and malathion. Application Huntington WV - 720 Every mite seen indoors has wandered should be made as directed on the label Lexington - 707 and repeated after 2 weeks if mites per- London - 742 in from outside. Louisville - 804 sist. Clover mites are plant feeders only. Mayfield - 849 They feed on sap from grasses and clo- Clover mites already indoors can be Paducah - 860 removed from surfaces with a vacuum Princeton - 1022 ver, and are especially numerous in Quicksand - 789 lawns with a heavy growth of succu- cleaner. Avoid wiping the clover mites Somerset - 820

OFFICE OF STATE ENTOMOLOGIST

S-225 Agricultural Science Center - North Lexington, Kentucky 40546-0091

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Interim State Entomologist— Fred Knapp, Ph.D Nursery Inspectors—Joe Collins & Carl Harper Phone: (859) 257-5383 Fax: (859) 323-1120 Email: [email protected] [email protected]