Fayette County Extension. Webworms Active Now Fall Webworm

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Fayette County Extension July, 2016 Cooperative Extension Service Fayette County Extension 1140 Red Mile Place Lexington, KY 40504-1172 Phone (859) 257-5582 Email: DL_CES_Fayette@email.uky.

Damaged by Fire Blight Don t forget to register for Gardener s Toolbox Classes, 2016. For a complete class descriptions and registrations information visit our website at: http://fayette.ca.uky.

1 Fayette County Extension July, 2016 Cooperative Extension Service Fayette County Extension 1140 Red Mile Place Lexington, KY Phone (859) By The Yard HORTICULTURE Webworms Active Now Fall Webworm Inside this issue: Volutella Blight on Boxwoods Japanese Beetles 3-4 Quick Tips for July 5 Recipe 5 Summer Management of Ornamental Pear Damaged by Fire Blight Don t forget to register for Gardener s Toolbox Classes, For a complete class descriptions and registrations information visit our website at: edu/files/gardeners_t oolbox_2016.pdf or call The first generation of fall webworm (FWW) is active now. The June brood is usually small and often goes unnoticed, while the August-September bunch is larger and occasionally can be a problem. These caterpillars are covered by pale green or yellow hairs and have rows of black spots along their backs (Figure 1). FWW can feed on over 90 species of deciduous trees and shrubs. Hickory, walnut, birch, black cherry, crabapple, and mulberry are among its favorites. Usually, the infestation is limited to a branch or two and impact is aesthetic rather than a threat to plant health. Fall webworm caterpillars work together to produce silk webbing that incorporates the leaves they are eating into a tent that becomes larger as they grow. The hairy caterpillars feed for about 4 weeks and top out at just over an inch in length. Management Infestations on small, newly-established landscape trees and shrubs should be watched and treated if necessary to prevent extensive defoliation and unnecessary stress. Large, established trees can tolerate an infestation, which is fortunate because their size can make treatment impractical. A few scattered tents can be left to natural control by beneficial insects. Accessible unsightly nests can be pruned and discarded, if practical. Tree and shrub insecticides containing Bt, spinosad, or pyrethroids can be used if chemical control is necessary and the sprayer can reach foliage around nests. Mimosa Webworm The two generations of the mimosa webworm follow a Figure 1. Fall webworm caterpillars. (Photo: Lee Townsend, UK) pattern similar to that of FWW, but they feed primarily on mimosa and honeylocust; thornless honeylocust (particularly cv. Starburst) is especially prone to attack. These dark-bodied caterpillars with 5 white stripes along the body thrash about when disturbed. By Lee Townsend, UK Extension Entomology

By The Yard Page 2 Volutella Blight of Boxwood Figure 1: Infected leaves turn from red/bronze to a straw-yellow color.

(Photo: Adam Leonberger, UK) Volutella blight is the most common disease of boxwood in the landscape.

Volutella Blight Facts Leaves begin to turn red or bronze, eventually becoming straw-yellow (Figure 1). Branches die back from tips and girdling may occur lower on stems (Figure 2).

2 By The Yard Page 2 Volutella Blight of Boxwood Figure 1: Infected leaves turn from red/bronze to a straw-yellow color. (Photo: Adam Leonberger, UK) The pathogen survives winter on affected branches and leaves from the previous season. Figure 2: Girdling or loose back may be present on lower stems. (Photo: Adam Leonberger, UK) Volutella blight is the most common disease of boxwood in the landscape. Volutella blight is caused by an opportunistic fungal pathogen that attacks leaves and stems of damaged or stressed plants. Winter injury, poor vigor, and wounds increase risk for Volutella blight. Volutella Blight Facts Leaves begin to turn red or bronze, eventually becoming straw-yellow (Figure 1). Branches die back from tips and girdling may occur lower on stems (Figure 2). Bark may also be loose on infected branches. In moist, humid weather, salmon-to-pink fruiting structures may be visible (Figure 3). American and English boxwood are susceptible. Disease development is favored by high humidity and temperatures between 65 and 75 F. The pathogen survives winter on affected branches and leaves from the previous season. Caused by the fungus Pseudonectric buxi (asexual stage Volutella buxi). Management Options Maintaining a sanitation program and promoting plant vigor are critical for disease management. Prune diseased branches. Prevent wounding, including improper pruning cuts. Maintain plant health with proper nutrition and irrigation practices. Avoid excess water. Maintain good air circulation by sufficiently spacing plants or by pruning dense growth. Gather and destroy plant debris. If disease continues to be a problem after following other management practices, fungicides may be used preventatively beginning in spring. Homeowners may use fungicides that contain mancozeb or copper. Always follow label directions when utilizing fungicides. Additional Information Homeowner s Guide to Fungicides (PPFS-GEN-07) Landscape Sanitation (PPFS-GEN-04) Woody Plant Disease Management Guide for Nurseries and Landscapes (ID-88) Boxwood Diseases (Penn State Extension) Boxwood (Buxus)- Volutella Leaf and Stem Blight {Canker} (Pacific Northwest Plant Disease Management Handbook) Volutella Blight Boxwood (Home & Garden Information Center, University of Maryland Extension) By Kim Leonberger, Extension Associate and Nicole Ward Gauthier, Extension Specialist, University of Kentucky Figure 3: Salmon or pink fruiting structures may be visible in periods of moist, humid weather. (Photo: Paul Bachi, UK

These white tufts help to distinguish them from similar metallic green or coppery colored beetles. Adults emerge from the ground in late May or early June.

3 By The Yard Page 3 Japanese Beetles Adult Japanese beetles are 3/8 inch long metallic green beetles with hard, copper-brown wing covers. Five small white tufts project from under the wing covers on each side, and a sixth pair at the tip of the abdomen. These white tufts help to distinguish them from similar metallic green or coppery colored beetles. Adults emerge from the ground in late May or early June. Individual beetles live about 30 to 45 days with activity concentrated over a four to six week period. Beetle numbers begin to decline in late July but some can be found as late as September. Japanese beetles can feed on about 300 species of plants, ranging from roses to poison ivy. Odor and location in direct sun seem to be very important factors in plant selection. The beetles usually feed in groups, starting at the top of a plant and working downward. While a single beetle doesn't eat much; group feeding by many causes severe damage. Adults feed on the upper surface of foliage, chewing out tissue between the veins. This gives the leaf a characteristic skeletonized appearance. Japanese beetles can fly as far as 5 miles but 1 to 2 miles is more likely. Usually, they make only short flights as they move about to feed. Local infestations spread as beetles move to favored food and egg-laying sites. Insecticides for Japanese Beetle Control Many insecticides are labeled for Japanese beetle control on landscape plants. Examples include acephate (Orthene Turf, Tree & Ornamental Insecticide), carbaryl (Sevin and many other brand names), cyfluthrin (Bayer Advanced Garden Multi-Insect Killer Concentrate), lambdacyhalothrin (Spectracide Triazicide Soil & Turf Insect Killer Concentrate), esfenvalerate (Ortho Bug-B- Gon Garden & Landscape Insect Killer Concentrate), and permethrin Spectracide Bug Stop Multi-Purpose Insect Control Concentrate and many other brands). Neem extracts (Bon-Neem) deter Japanese beetle feeding but may not be adequate against high populations. Direct spray applications of insecticidal soap kills Japanese beetles on contact but does not provide any residual protection. Here are some points to keep in mind when using insecticides for beetle control: Japanese beetle flight is greatest on clear days with temperatures between 84 o and 95 o F and winds less than 12 miles per hour. This can bring new beetles into your landscape to challenge any control program that you may have. When these conditions exist, check plants frequently to see if beetles are starting to feed again. A few beetles on plants, or some moderate damage, will bring in more. Japanese beetles apparently produce aggregation pheromones that will attract more males and females to feed and find potential mates. In addition, volatile odors from damaged plants may attract more beetles. These conditions also can keep beetle numbers high. Keeping numbers and damage low can mean fewer new arrivals. Japanese beetles begin to feed at the tops of plants and move down as defoliation occurs. This makes damage obvious, in terms of brown leaves and esthetic damage, but also can pose coverage problems on large trees. Hose end sprayers may allow applications to reach the target but spray drift and applicator exposure are potential problems. Some of the effective insecticides for Japanese beetle control, such as carbaryl (Sevin) and the pyrethroids (permethrin and others) can contribute to Continued on page 4 Japanese beetles can feed on about 300 species of plants, ranging from roses to poison ivy. Leaves skeletonized by Japanese beetles

By The Yard Page 4 Japanese Beetles (con t.) Japanese beetle adult. Photograph courtesy of David Cappaert/University of Michigan and IPMImages.org.

Watch closely for signs of these pests and use acephate or malathion if needed. While these insecticides have a shorter residual life, they may help to reduce problems with secondary pests.

4 By The Yard Page 4 Japanese Beetles (con t.) Japanese beetle adult. Photograph courtesy of David Cappaert/University of Michigan and IPMImages.org. One of the easiest ways to remove beetles from small plants is to shake the plants early in the morning (about 7 a.m.) when temperatures are low and the beetles sluggish. build-ups of mites or aphids. Watch closely for signs of these pests and use acephate or malathion if needed. While these insecticides have a shorter residual life, they may help to reduce problems with secondary pests. Repeated applications may be necessary because of the relatively short residual effect of the products. Also, a significant rainfall shortly after an application may reduce the insecticide deposit below effective levels. Natural Controls The hard body of the Japanese beetle may make them relatively unattractive to many predators, such as birds. Some may be killed by predatory insects but this is probably infrequent. A few species of wasps and flies have been imported an attempt to control the beetle in the US but with only establishment has been limited, so far. Collecting Beetles Hand collecting can be used to protect valuable plants when beetle activity is relatively low. The presence of beetles on a plant attracts more beetles. When you remove beetles daily by hand from a plant, only about half as many are attracted to that plant compared to those on which beetles are allowed to accumulate. One of the easiest ways to remove beetles from small plants is to shake the plants early in the morning (about 7 a.m.) when temperatures are low and the beetles sluggish. The beetles may be killed by shaking them into a bucket of soapy water. Trapping Beetles Japanese beetle traps are sold in many garden centers. Commercially available traps attract the beetles with two types of baits. One mimics the scent of virgin female beetles and is highly attractive to males. The other bait is a sweet-smelling food-type lure that attracts both sexes. This combination of ingredients is such a powerful attractant that traps can draw in thousands of beetles in a day. Research conducted at the University of Kentucky has shown that the traps attract many more beetles than are actually caught. Consequently, susceptible plants along the flight path of the beetles and in the vicinity of traps are likely to suffer much more damage than if no traps are used at all. In most landscape situations, use of Japanese beetle traps probably will do more harm than good. If you experiment with traps, be sure to place them well away from gardens and landscape plants. By: Rick Bessin, Entomology, University of Kentucky LEXINGTON LION S CLUB BLUEGRASS FAIR FLOWER & VEGETABLE SHOW COME ON OUT - SHOW WHAT YOU GROW July 16 & 17, 2016 Show hours: 3:00 p.m. to 10:00 p.m. Masterson Station Park, Lexington, KY

By The Yard Page 5 Quick Tips for July Now is the time to plan and plant a fall garden.

Allow a little more time to mature than the seed package says as cooler nights will slow growth somewhat.

If you have a serious grub problem apply controls in late July or August.

Make sure to use a de-chlorinator every time to protect your fish. Water lilies will benefit from regular feeding.

Spray in the early morning or late evening when temperatures are cooler. Monitor evergreens for spider mite damage.

If you see signs of browning shake the branch over a white surface, if you see tiny moving red specks you likely have mites.

5 By The Yard Page 5 Quick Tips for July Now is the time to plan and plant a fall garden. Most plants with shorter growing seasons can be grown in the fall and often produce better results. Allow a little more time to mature than the seed package says as cooler nights will slow growth somewhat. When watering, try to avoid wetting foliage or watering late in the evening as both can promote disease. If you have a serious grub problem apply controls in late July or August. The larvae are much easier to control while they are small. Garden ponds will need to be topped off regularly in the heat. Make sure to use a de-chlorinator every time to protect your fish. Water lilies will benefit from regular feeding. If you aren t getting many blooms feeding may help. Do not spray chemicals in the heat of the day. Many plants can be damaged. Spray in the early morning or late evening when temperatures are cooler. Monitor evergreens for spider mite damage. Drought stressed plants are particularly at risk. If you see signs of browning shake the branch over a white surface, if you see tiny moving red specks you likely have mites. Minor infestations can be treated with a daily spray from the hose. Larger problems may need chemical control. Remove spent blooms from flowering annuals and perennials to promote more bloom. If your late blooming perennials (Asters, Goldenrod, Butterfly bush, Mums, etc.) are already tall and threatening to flop, prune them back to 1 in height. This will result in a fuller, sturdier plant that will loom slightly later than normal.

By The Yard Page 6 Summer Management of Ornamental Pear Damaged by Fire Blight Questions have been plentiful regarding fire blight damage in flowering pear, apple, crabapple, cotoneaster, hawthorn,

Often, damage is not noticed until later in the season when branches die completely. Although symptoms become more obvious during late spring, the fire blight bacterium is not currently active.

Current Disease Management Current recommendations indicate that pruning of blighted twigs and cankered branches should be delayed until winter when risk of disease spread is lowest.

6 By The Yard Page 6 Summer Management of Ornamental Pear Damaged by Fire Blight Questions have been plentiful regarding fire blight damage in flowering pear, apple, crabapple, cotoneaster, hawthorn, and pyracantha. During March or April, pathogenic bacteria infected flowers or young shoots. Now, shepherd s crooks (Figure 1) and spur dieback (Figure 2) are becoming more prominent. Often, damage is not noticed until later in the season when branches die completely. Although symptoms become more obvious during late spring, the fire blight bacterium is not currently active. Hot summer temperatures suppress bacterial growth, and plants are able to compartmentalize and wall off spread. Thus, visible symptoms are the result of early infections. Current Disease Management Current recommendations indicate that pruning of blighted twigs and cankered branches should be delayed until winter when risk of disease spread is lowest. Under certain circumstances, homeowners or commercial landscape contractors may choose to prune infected branches during the growing season. Only young, vigorous trees should be considered, and care should be taken to prevent bacterial spread. Always avoid working when plants are wet. Cut branches at least 6 to 8 inches below cankers, disinfesting pruners between each cut (10% Lysol disinfectant, 10% bleach, or rubbing alcohol). Ideally, winter pruning is recommended. Future Disease Management Disease management includes both cultural practices and preventative bactericides. Because the fire blight bacterium overwinters in cankered branches, removal of diseased plant tissue before bud break (mid- to late winter) is critical. Copper applied as buds swell (late dormancy or silver tip) reduces build-up of bacterial cells, especially during warm rainy spring seasons. Streptomycin applications are only recommended for fruiting apple and are not labeled for landscape use. Resources Fire Blight of Apple (PPFS-FR-T-03) Flowering Crabapple (ID-68) Homeowner s Guide to Fungicides (PPFS-GEN-07) Landscape Sanitation (PPFS-GEN-04) By Nicole Ward Gauthier, Extension Plant Pathologist and Kim Leonberger, Extension Associate, University of Kentucky Figure 1: Infection of young shoots cause shepherd s crook symptoms. (Photo: Nicole Ward Gauthier, UK) Figure 2: Infection of flower spurs travels down into twigs. Cankers can girdle branches, restricting water uptake to tops of branches. (Photo: Nicole Ward Gauthier, UK) Plan now to join us at the Lexington Lions Club Bluegrass Fair July 14-24, 2016 Watch for the fair booklet in the mail soon FAYETTE COUNTY EXTENSION OFFICE WILL BE CLOSED ON MONDAY, JULY 4 TH

Benefits to Citizen Scientists: Connect with nature! YOUR HELP IS NEEDED!

monarch butterflies and milkweed flowers.

To reach our goal we need members of the Lexington community to commit to being a citizen scientist.

7 Benefits to Citizen Scientists: Connect with nature! YOUR HELP IS NEEDED! CITIZEN SCIENCE MONARCH BUTTERFLIES Research Join UK biologists in a summer long study to better understand the interaction between monarch butterflies and milkweed flowers. Our goal is to determine how important monarchs and other pollinator species are to milkweed reproduction. To reach our goal we need members of the Lexington community to commit to being a citizen scientist. This citizen science study is one part of three part study aimed at restoring habitat for the beautiful monarch butterfly throughout Lexington. Help save the beautiful monarch butterfly. You will be compensated for your time. Sign up today! STEPHEN ZUMDICK s.zumdick@uky.edu Please contact me if you have any questions. FAQ on the back.

8 NONPROFIT ORG US POSTAGE PAID Fayette County Cooperative Extension 1140 Red Mile Place Lexington, KY Lexington, KY PERMIT 112 RETURN SERVICE REQUESTED Fayette County Jamie Dockery County Extension Agent for Horticulture Cooperative Extension Service Fayette County Extension Service 1140 Red Mile Place Lexington, KY (859) Educational programs of the Kentucky Cooperative Extension Service serve all people regardless of race, color, age, sex, disability, or national origin. By the Yard Newsletter Enclosed UNIVERSITY OF KENTUCKY, KENTUCKY STATE UNIVERSITY, U.S. DEPARTMENT OF AGRICULTURE AND KENTUCKY COUNTIES COOPERATING The Cooperative Extension Service prohibits discrimination in its programs and employment on the basis of race, color, age, sex, religion, disability, or national origin. To file a complaint of discrimination, contact: Rosemary Veach, UK College of Agriculture, Lexington, KY 40546, or Terry Allen, Associate Vice President of Institutional Equity, Lexington, KY 40546, or the Secretary of Agriculture, USDA Director, Office of Civil Rights, Room 326-W Whitten Bldg., 14th and Independence Ave. SW, Washington, D.C

Bourbon County Horticulture Newsletter

July-August 2017 Bourbon County Horticulture Newsletter Bourbon County Cooperative Extension Service Inside this issue: Summer Gardens 2 Japanese Beetles 3 Organic Fact Sheet Turf Beetles and Wasps 4 Maple