Spring is a great time of the year. With life emerging from its long winter sleep, it’s among nature’s most active seasons. But spring is also a time when plant pests emerge. These pests can ravage your trees and kill them. Basically, you can divide tree pests into three broad categories—sap-sucking insects, wood borers, and defoliators.

Pests invade trees when they’re under great stress. Pests introduced from outside their native range can severely impact crops and natural tree populations, generating billions of dollars of economic and ecological damage. However, what insects you’ll need to watch out for this summer depends on your location.

Tree pests cause tremendous to natural and managed land annually. Most tree damage is caused by 20-22 common insect pests. These pests can devastate a tree if left untreated and cause extensive economic damage by destroying landscape trees that has to be removed and replaced. The impacts of pests are often made worse by climate change, which may allow additional pest life cycles per annum.  

Not all pests are deadly, however. Some play critical roles in natural and managed systems, contributing to carbon cycling and forest regeneration. They may even contribute to shaping patterns of global tree diversity. Below are five pests to look out for and descriptions of telltale signs that they have invaded your trees:

1.      Arborvitae leafminer

If you see brown foliage now on your “Green Giant” and “Emerald Green” cultivars, it’s a sign that these pests are feeding on your plant’s leaves. This leafminer pest is a small caterpillar, green or brownish, with a dark head and a spot just behind its head. Mature caterpillars generally appear between April and June. While this pest likes all arborvitae varieties, they prefer American pyramidal, globe, and golden arborvitae.

2.      Cedar Rust

Cedar apple “rust” can affect the health and vigor of your apple trees by causing early defoliation and reducing fruit quality. They present as orange gelatinous spheres and indicate the presence of fungal spores from the Gymnosporangium family, which can later infect Malus species. Cedar rust is especially harmful to Junipers. Severe infections of this disease, which first appear on leaves as small greenish spots and then gradually enlarge and change color, can kill a tree.

3.      Holly Leafminer

As the name suggests, it feeds on English, American, and Japanese hollies. If you see tiny green blisters on a lower leaf’s surface, chances are good the female of this pest has laid eggs there. The Holly leafminer “causes the presence of yellow, brown, or reddish mines on the leaves. In the beginning, the mines are narrow and winding. But they then become large blotches as the larvae overwinter in the leaf. The upper and lower surfaces of leaves remain after feeding and are easily separated. Larvae are yellowish and about 1/16″ long. The adult is a small black fly.

4.      Boxwood Leafminer/Blight

These pests are among the most destructive—and deadly— of the boxwood insect pests. The larvae feed on the tissue between the leaves’ outer surfaces, producing blotch-shaped mines in the boxwood leaves. Circular leaf lesions are a crucial symptom of boxwood blight, as are leaf yellowing and leafminer injury blistering. Infested leaves appear blistered from late summer through the following spring. New leaves, however, don’t show signs of mining until deep into summer, when the larvae are larger. Premature leaf drops may result from heavy infestation by fall or early spring.

5.      Pine Needle Blight

A common fungal disease among pines, especially mugho and Japanese white pines, pine needle blight attacks pine needles, causing spots, blights, and premature defoliation. Initially, spots emerge in summer or late fall. It’s a group of diseases. Cyclaneusma needle cast symptoms appear as light green to yellow spots on infected 2-year-old or older pine needles. Dothistroma needle blight causes yellow to tan spots in the fall. Lophodermium needle cast appears in late fall to early spring. It presents as brown spots with yellow margins on young needles. Brown bands form later.  

These five pests are common in the Northeast. But don’t panic if you see one or more of them on a tree’s leaves or something foreign on its bark. Instead, get to work diagnosing the problem and deciding on the best treatment for the pest. Treatment for these pests, however, varies. So, if you need help treating them, contact the RI Tree Council as soon as possible. We’ll help you eliminate these pests and boost your tree’s health.

John Campanini is technical director of the Rhode Island Tree Council (RITree). A graduate of the University of Rhode Island, he was city forester for Providence for more than twenty years before retiring.

by John Campanini

Technical Director, RI Tree Council

Mature trees provide numerous benefits for both you and your property. But caring for them is critical to ensuring they remain healthy enough to provide these benefits. You have even more incentive to maintain the tree’s health of the tree if the tree is historical. Generally speaking, mature trees require the same care as younger trees.

But older trees are much less tolerant of sudden changes—even positive ones. So, if you think an older tree is in trouble, don’t hesitate to call an arborist or the Rhode Island Tree Council for help. They can provide strategies that can help you save an older tree. In the meantime, this article provides proven tips on caring for and preserving mature trees.

Common Diseases Affecting Mature Trees

Mature trees can suffer from a variety of disease problems. Anthracnose, for instance, which causes unsightly dark, sunken lesions on leaves, stems, and flowers is common among mature deciduous trees, especially sycamore, ash, and oak. Tree diseases weaken trees and make them more vulnerable to severe storms. Common diseases affecting mature trees include root rot, fungal infections, and bark beetles.  

• Root rot is a deadly disease that can ravage trees. It can weaken a tree so much that it leans or breaks near the soil line. Wilting and discoloration, and dropping of a plant’s lower leaves are all signs your tree has this disease. Root rot types include phytophthora, armillaria, black, and cotton. All types of root rot are fatal. So, your best bet to preserve an older tree is to prevent this disease from occurring.
•  Tree fungus is common among trees. Once fungus spores contact a tree, they grow, enter, and feed on it. But not all tree fungi are bad. Some even benefit trees. If you see mushrooms or other fungi growing around or on a tree, chances are good your tree has a fungus. Other fungi, however, are hidden below ground. Then there are those funguses that look different than expected. The loss of vigor or the discoloration of leaves is a sure sign that your tree has a fungus.
• Bark beetles breed between the bark and wood of a tree. Some species attack living trees. But most feed on weakened, dying, or dead trees. Bark beetles tend to attack one part of a tree. Some species of bark beetles speed the decomposition of wood and forest renewal. Other species can invade and kill a tree. Trees attack bark beetles by releasing their pitch or sap, which appears as reddish-brown or white blobs on the tree. If the blob is white, the tree has successfully defended itself.

If you think your older tree has any of these common problems, you need to eliminate the threats as quickly as possible. Letting them linger can kill an older tree.

Pruning Older Trees to Enhance Growth 

Pruning an older tree is essential to maintaining its health. Pruning enhances the tree’s beauty, promotes its growth and development, and improves its shape and structure. Pruning also reduces the risk of disease and pests invading a tree while improving air circulation and supporting its longevity by encouraging new growth. 

But you need to prune wisely and at the right time. If done incorrectly or at the wrong time, pruning can harm older trees or, at the very least, inhibit their growth. So, when is the best time to prune an older tree? The best time to prune older trees is when you see dead branches. Cut them away carefully so you don’t cause a more critical wound. But be careful when pruning branches. You don’t want them to fall and injure someone or harm your property.

 Boosting Soil Health Protects Mature Trees

Enhancing soil health for older trees is another way to protect older trees from pests, insects, and diseases. Using natural fertilizers like compost, manure, and bone meal to enrich the soil with essential nutrients, for example, can boost soil health. Applying the proper soil preparation, irrigation, and fertilization techniques boost your tree’s health and make it robust enough to withstand common insect and pest infestations.

 Watering Older Trees Helps Them Thrive

 

Watering the appropriate amount for your tree type can also help mature trees thrive. Minus a soaking rain, water regular monthly deep watering is recommended. You may also want to remove competing plants near a tree. Removing built-up soil from around the root crown also helps. It can hide defects, create areas of decay, or trap moisture from around the root crown, creating the perfect environment for fungus.

Mature trees are an essential part of our environment, providing many benefits to people and the environment. They can provide shade, cut air pollution, reduce stormwater runoff, and act as a habitat for wildlife. Older trees can also be treasures with great sentimental value. They often have much history attached to them—especially if you live in a house you were born and raised in. But you must take care of them to keep them healthy and strong. So, don’t hesitate to call an arborist or the Rhode Island Tree Council if your older tree needs help.

John Campanini is technical director of the Rhode Island Tree Council (RITree). A graduate of the University of Rhode Island, he was city forester for Providence for more than twenty years before retiring.

PROVIDENCE, RI, May 19, 2023 — Rhode Island Tree Council (RI Tree) recently held this year’s Arbor Day celebration at Miantonomi Park, Hillside Avenue, Newport, RI. The city of Newport hosted the event, the Newport Tree Conservancy, and the Newport Tree and Open Space Commission. The event’s primary sponsor was the Rhode Island Energy Corporation, PPL. The event’s secondary sponsors were the Rhode Island Tree Council and the Rhode Island Department of Environmental Management.  

As part of the day’s ceremonies, Governor Dan McKee read the official state Arbor Day proclamation, with Newport’s mayor, Xaykham-u’Xay-Khamsyvoravong, in attendance. Doris Alberg, RI Tree chairperson, presented sponsors awards to Rhode Island Energy and hosts awards to the city of Newport Tree and Open Space Commission and Newport Tree Conservancy. Terry Gray, Director of RI DEM, and Lou Allard, Urban, and Community Forestry Program, co-presented the 2022 Tree City USA award to the following cities.

Barrington (5 years), Bristol (22 years), Central Falls (8 years), East Providence (29 years)

Jamestown (21 years), Middletown (5 years), Narraganset (12 years), Newport (32 years), Pawtucket (17 years), Portsmouth (17 years), Warren (21 years), and Warwick (23 years).  Providence (37 years) was the Growth Award Recipient. Johnson & Wales University and Salve Regina University received this year’s R.I Tree Campus Higher Education award.

Students from the first-grade class of the Chairborne Pell Elementary School displayed their tree crafts. RI Tree also planted five Arbor Day trees, including the Arbor Day ceremonial red oak at the park. RI Tree also planted the Scarlet Oak, Greensleeves Dogwood, and Sugar Maple trees at the park.

Rhode Island has had a long history with Arbor Day. According to the RI Department of Education records, the first event held in Rhode Island to honor trees occurred on April 29, 1886. Sponsored by the Barrington Rural Improvement Society, the ceremony took place on public land near the railroad station in West Barrington. 

Assisted by Society members, school children planted an American elm and dedicated it to the memory of the 16^th President of the United States, Abraham Lincoln. Many more would follow. In 1892, the RI Department of Education initiated an Arbor Day Program for school children to be held in the spring of each year over the next five decades (ending 1939).

Spring is a great time to plant new trees. The cool weather enables trees to establish roots before the summer heat stimulates new top growth. While you can plant healthy balled and burlapped (or container) trees throughout the growing season, you must provide good care for them to take root and grow. Make sure you have enough water to help them grow and, make that you locate all underground utilities before digging.

How well a new tree grows after planting, however, depends primarily on four things:

• Type of tree selected
• Planting location
• Care provided during planting
• Follow-up care after planting 

Attending to these factors conscientiously eliminates plant stress. You may need to prune a new tree after planting, however. If you do, prune sparingly. You can do corrective pruning after the tree experiences a full year’s growth.

The International Society of Arboriculture recommends the following nine steps when planting a new tree:

1. Identify the trunk flare at the bottom of the tree’s base. Make sure it’s visible after planting.
2. Dig a shallow broad planting hole about two times larger than the root ball.
3. Remove the containers or cut away the wire basket.
4. Place the tree at the proper height. Lift the tree by the root ball when placing it in the hole.
5. Straighten the tree in the hole. Once planted, a tree is difficult to reposition.
6. Fill the hole gently but firmly. Water periodically by backfilling, and avoid fertilization at this time.
7. Stake the tree only when planting bare root stock or when planting at windy sites. Remove after a year of growth.
8. Mulch the tree’s base. Mulch helps holds moisture, moderates soil temperature extremes, and reduces grass and weed competition. Avoid filling in mulch to the tree’s base.
9. Provide follow-up care. Keep the soil moist but not water-logged. Water once a week, barring rain. Water more frequently during hot, windy weather.

Best Spring Flowering Trees to Plant

Below are four of the best spring-flowering trees to plant in Rhode Island.

·         Flowering Cherry 

These trees come in a wide variety of shapes and sizes. Many varieties bloom in springtime and last for several weeks. Cherry trees work well in residential gardens because they require minimal care. All are beautiful. Distinguishing characteristics include the number of petals, the color of the blossoms, and their fragrances, leaves, and blooming season. Flowering cherry trees perform best in full sun in moist, relatively well-drained soils. Watch for caterpillars, leaf-mining moths, bacterial cancer, and blossom wilt.

·         Magnolias 

Like the cherry tree, the magnolia tree is best known for its flowers. Among the first trees to bloom in the spring, magnolia trees have large flowers and a sweet, heady fragrance. Their tulip- or star-shaped flowers are often as large as saucers when fully opened. The tree’s foliage and fruit are also attractive. Magnolia trees come in several varieties, are long-lived, and are easy to plant. The best time to plant them from seeds is in the spring. These hardy trees need suitable soil, light, water, and feeding to thrive.

·         Dogwood  

These woodland trees appear in various forms around the U.S., giving us a beautiful and elegant spring spectacle. A good choice in New England, where it’s cooler, is the Pagoda Dogwood. These trees have wide graceful branches growing horizontally into layers, each featuring white flowers in late spring. In partially-shaded gardens, the dogwood’s whiteness makes a stunning show. Unfortunately, a severe disease affecting all types of dogwood is anthracnose. A fungus known as Discular Destructiva is also a severe threat.

·         Crabapple

The flowering crabapple tree is among the most prized of all spring-flowering trees. They’re a staple of landscape gardening.  Known for their spectacular display of magnificent blossoms and colorful fruit in the fall, these trees bloom for four-to-five weeks in mid-spring. The combination of rich red buds opening to pure white blossoms pumps up a floral display’s beauty. Unfortunately, crabapple trees in New England are susceptible to four significant diseases—apple scab, fireblight, cedar-apple rust, and powdery mildew.

Buying a new tree and planting it is a good investment. It offers a wide range of benefits, including boosting the value of your property by about 7%. In affluent areas, trees can boost the value of a home by as much as 10-15%. However, how well a tree does depends on the tree selected, where you plant it, the care you provide during planting, and the follow-up care you offer.

Contact RI Tree for more tips on planting a new tree or for a copy of the International Society of Arboriculture’s brochure on New Tree Planting.

John Campanini is the technical director of the Rhode Island Tree Council (RI Tree). A University of Rhode Island graduate, he was City Forester for Providence for over twenty years before retiring.