INLA Joint COMMITTEE MEETING

Join us... and bring your good ideas!

Tuesday, March 8, 2023 • 2:00 – 4:00 pm at Automatic Supply (116 Shadowlawn Dr, Fishers, IN 46038)

The Indiana Nursery and Landscape Association serves its members in the industry through education, promotion, and representation. The planning and implementation of most INLA activities are handled by volunteer groups. All groups are supported by INLA staff. INLA committees have ongoing, results-oriented tasks. The interaction between group members promotes effective planning and evaluation of tasks.

YOU CAN HELP !

Sign up now! Review the following list of committees and check off those of interest to you. Return this form to the INLA office via email or mail and you will be registered to attend.

VOLUNTEER SIGN-UP FORM

I am interested in giving some time to work in the following areas:

 Awards Committee: Organize selection of annual awards.

 Communications Committee: Newsletter, website, directory, etc.

 Education Committee: Works to enhance educational opportunities for all members of the industry, ranging from those with extensive practical experience to new members of the industry and students preparing for green industry careers.

 IAH Committee: This committee works closely with educational and vocational-technical levels and oversees the Indiana Accredited Horticulturist Program. This meeting will be held in northern Indiana at an alternate date.

 Legislative Committee: Works in partnership with the Green Industry Alliance.

 Membership Committee: Promotes the INLA by securing new members and assisting current members by providing member services.

 Summer Meeting: Planning and organization of annual INLA Summer Meeting.

 Trade Show Committee: Plans and conducts the premier trade show for the industry in Indiana annually.

 Landscape Industry Certiied (CLT) Committee: Work on this national certification committee to implement the handson field exam.

 FFA Committee: Volunteer to judge state and national career development events. (This committee will not meet; however, you can volunteer to judge these industry-related events in April and October.)

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Company: ____________________________________________________________________________________________

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City, State, Zip: ________________________________________________________________________________________

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My primary area of business (check all that apply):

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To register, please email to rhaggard@inla1.org or mail to: INLA, 7915 S. Emerson Ave., Ste. 247, Indianapolis, IN 46237

Indiana Nursery & Landscape Association • Phone: 317-889-2382 or 800-443-7336 • www.inla1.org

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Top Ten Pests and Diseases Reported in 2022

By Diane Turner & Catherine Terrell

Nursery Inspectors with the Indiana Department of Natural Resources Division of Entomology and Plant Pathology (IDNR DEPP) put together a “Top Ten” list of their most encountered abiotic and biotic stressors at the end of each growing season. These lists are compiled into Table 1, so we see the most common pests in Indiana nurseries during the 2022 season.

Northern Region*

Insects

Aphids (4**)

Japanese Beetles (4)

Diseases/Abiotic

Apple Scab (4)

Herbicide Injury (4)

Red Headed Flea Beetle (4) Leaf Spots (4)

Bagworm (3)

Powdery Mildew (4)

Lace Bugs (3) Botrytis (3)

Spider Mites (3)

Drought Stress (3)

White Pine Weevil (3) Nutrient Deficiency (3)

Fall Webworm (2) Tar Spot (3)

Leafhoppers (2)

Thrips (2)

Anthracnose (2)

Needlecast (2)

Southern Region*

Insects

Japanese Maple Scale (5)

Aphids (4)

Diseases/Abiotic

Apple Scab (4)

Powdery Mildew (4)

Red Headed Flea Beetle (4) Drought Injury (3)

Azalea Lace Bug (2) Rust (3)

Lace Bugs (2)

Mites (2)

Oystershell Scale (2)

Thrips (2)

Whitefly (2)

Bagworm (1)

Anthracnose (2)

Botrytis (2)

Frost damage (2)

Herbicide Damage (2)

Leaf Scorch (2)

Leaf Spots (2)

Apple Scab (Venturia inaequalis)

One of the most reported diseases throughout Indiana for 2022 was apple scab, caused by the fungal pathogen Venturia inaequalis. Eight of our nine inspectors across the state listed this disease highest on their Top Ten lists. The spread of apple scab can be diminished by a few simple practices easily implemented in the nursery industry.

The primary hosts for apple scab are flowering crabapples (Malus spp.) and hawthorn (Crataegus spp.). However, this disease may also be found on mountain ash (Sorbus spp.), firethorn (Pyracantha spp.) and loquat (Eriobotrya spp.). Apple scab may cause trees to look unsightly and aesthetically unpleasing. Infections are initiated in early spring on emerging and young leaves. The fungal infection develops slowly under cool, wet conditions causing symptoms to slowly progress two to three weeks after inoculation. Early lesions appear as lighter green areas compared to the surrounding leaf tissue. Lesions gradually increase in size and become olive-colored with a velvety texture due to asexual spore production (conidia). Scab lesions that form on young leaves may expand to more than one centimeter in diameter.

Apple scab results in symptoms on most upper plant parts, most notably leaves and fruit. However, petioles, flowers, sepals, pedicels, young shoots, and bud scales can also become infected. Affected tissues eventually may become distorted and puckered, with leaf lesions eventually becoming cracked and torn. Severely infected leaves may prematurely drop from trees. In an unusually bad apple scab year, it may be common for susceptible trees to suffer near complete defoliation.

Two to three consecutive seasons of defoliation can weaken trees, resulting in a greater susceptibility to other stresses such as freeze damage, insect injury, or other diseases. Fruit lesions are generally blistered and "scabby" in appearance, with a distinct margin. The earliest noticeable symptom on fruit is water-soaked areas that rapidly develop into velvety, olive green to brown lesions. Infections of young fruit cause fruit distortion as healthy tissue continues to grow.

The use of resistant varieties is the easiest way of managing apple scab of flowering crabapples, resulting in a tree that adds beauty to the landscape throughout the year. Luckily, many desirable cultivars of resistant flowering crabapples are available to Indiana nursery growers. Check out Purdue Extension publication ID-217-W to find a list of available crabapple cultivars that are less prone to apple scab.

Apple scab on hawthorn and other tree species can be managed with a combination of cultural and chemical control methods. Since fallen leaves harbor the scab fungus and provide inoculum (fungus that overwinters and starts the disease process again) for spring infection, raking and removal of leaves is a necessary sanitation practice. A flail mower which mulches leaves may also aid in their breakdown and reduce overwintering inoculum. Also, be sure to routinely thin your trees to open the canopy which will improve airflow. Thinning will promote rapid drying of leaves which is less favorable for apple scab development.

Nursery trees that are susceptible to apple scab need to be sprayed each year on a regular schedule to prevent infection. The most critical time to apply fungicides is April and May in Indiana before symptoms appear. Generally, a minimum of three to four sprays in the spring are required for adequate control of apple scab. Be sure to read and follow all label instructions of the fungicide(s) that you select. Proper preparation before application ensures that you use the correct product in the safest and most effective manner possible.

Japanese Maple Scale (Lopholeucaspis

japonica)

Pests associated with warm weather have and will continue to move north due to the shifting in hardiness zones in North America. One pest that was common in southern Indiana in 2022 was the Japanese Maple Scale (JMS). It is important to keep an eye out for new pests in your area as the seasons change and the weather gets warmer.

The Japanese maple scale (Lopholeucaspis japonica; JMS) is an exotic armored scale insect, meaning it is a true bug (Hemiptera) with a straw-like mouth. Females produce a dark brown oyster shell-shaped, protective waxy scale that is not attached to them to avoid predation and are 1-2 mm in size. JMS is polyphagous, meaning it feeds on 45 genera of plants; a few examples include: apple, ash, cherry, dogwood, elm, lilac, maple, redbud, serviceberry, and yellowwood. The mobile, first-instar immature stage of JMS are known as “crawlers” and can be purple in color. They are typically found on the bark of the tree in cracks and on rough areas, however, they can occasionally occur on foliage as well.

Adult female JMS that have overwintered lay clutches of around 25 eggs under the oyster shell-shaped waxy cover they use for protection, in spring. These eggs will hatch into “crawlers” which is the only mobile stage for this insect. JMS, and other armored scales, will typically settle on the interior areas of host plants to avoid predation. After finding their own feeding spot, JMS crawlers will settle down and lose their legs and antennae as they have their next molt. These immobile scales will molt an additional two times before they reach reproductive maturity. Although there are males of this species, females can lay viable eggs without sexual reproduction, known as parthenogenesis. This insect can have one to two generations a year depending on hardiness zone. Some areas experience a second generation.

Trees that have a light infestation of JMS may not experience any symptoms, however, as the infestation grows so will noticeable symptoms. Armored scales such as JMS damage host plants by inserting their straw-like mouth into trees and draining nutrients. With moderate infestations, trees can experience leaf yellowing and loss along with stagnated growth. In heavy infestations, JMS can cause dieback of twigs, branches, and even entire plants.

The first step for treatment with any pest is monitoring and inspecting infested areas to assess if pest management is necessary. Check the interior of host plants along with tucked away areas where JMS adult females might be settled in from the winter. Check old JMS scales to see if there are any small openings suggesting parasitic wasps are keeping populations at bay along with any other natural predator,

IDNR Top Ten Pests/Diseases

(continued from page 11) such as lacewings and lady beetles. In early spring, keep an eye out for the purple crawler stage by placing sticky monitoring cards around the host plant. Larger infestations may require pruning of the host plant and destruction of heavily infested material. Additionally, considering the stress a plant may be experiencing could be a factor in infestation levels as more stressed plants are easier targets. For the best results with chemical control, aim for peak crawler activity as adults will be harder to manage due to their protective shell. Broad-spectrum pesticides may not be the best treatment option for JMS due to their extended crawler emergent window and may only cause more harm towards beneficial insects.

Interested in learning about common nursery problems or want to know more about what inspectors are finding in your area? Subscribe to our weekly review and view archives of previous newsletters at www.in.gov/dnr/entomology/entomology-weekly-review/.

Questions about pests or pathogens in your nursery? Visit our website for inspector contact information at dnr.IN.gov/entomology. General questions can be sent to DEPP@dnr.IN.gov. About the authors:

Diane Turner (DTurner2@dnr.IN.gov) lives in Noblesville and is a nursery inspector for central Indiana. Catherine Terrell (CTerrell@dnr.IN.gov) lives in Lafayette and is a nursery inspector for Tippecanoe and surrounding counties. Both inspectors joined the DEPP team in 2022.

References

Boggs, J. (2020, May 7). Japanese Maple Scale (JMS). Bygl.osu.edu. https://bygl.osu.edu/node/1554

Frank, S. (2019, August 29). Armored Scale Identification and Management on Ornamental Plants | NC State Extension Publications. Content.ces.ncsu.edu. https://content.ces.ncsu.edu/ armored-scale-identification-and-management-on-ornamental-plants

Frank, S., & Dale, A. (2015, July 3). Japanese Maple Scale, Lopholeucaspis japonica (Cockerell), Hemiptera: Diaspididae | NC State Extension Publications. Content.ces.ncsu.edu. https://content.ces.ncsu.edu/ japanese-maple-scale-lopholeucaspis-japonica-cockerell-hemiptera-diaspididae

Gauthier, N. (2018). Apple scab. Apple Scab; The American Phytopathological Society. https://www.apsnet.org/edcenter/ disandpath/fungalasco/pdlessons/Pages/AppleScab.aspx

Hoover, G. (2013, June). Japanese Maple Scale. PennState Extension. https://extension.psu.edu/japanese-maple-scale

Joseph, S., & Hudson, W. (2019, November 20). Japanese Maple Scale: A Nursery and Landscape Pest. Extension.uga. edu. https://extension.uga.edu/publications/detail.html?number=C1168

Sadof, C., & Beckerman, J. (2018, May). Crabapples Resistant to Apple Scab and Japanese Beetle in Indiana. Purdue University Entomology Extension. https://extension.entm.purdue.edu/publications/id-217.pdf

Scheufle, S., & Brazee, N. (2015, March 6). Japanese Maple Scale. Center for Agriculture, Food, and the Environment. https://ag.umass.edu/landscape/fact-sheets/japanese-maple-scale

Talabac, M. (2022, August 16). Japanese Maple Scale in Home Landscapes | University of Maryland Extension. Extension. umd.edu. https://extension.umd.edu/resource/japanese-maple-scale-home-landscapes

Beckerman, Janna (2006). Apple Scab on Tree Fruit in the Home Orchard (BP-1-W). Department of Botany and Plant Pathology, Purdue University. Entomology & Dept. of Botany and Plant Pathology.

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