Pest Control Management
Thousands of insect species and disease organisms are attracted to trees and shrubs. Many of these cause little harm and are of no concern. It is our responsibility to know the difference. It’s the insects and diseases that are capable of severely damaging or even killing these plants that we must manage. Early detection, identification, diagnosis, and a recommended treatment program by a qualified arborist are essential aspects of this holistic and preventative care. Some of the most common pests and pathogens are noted below. Our newsletters point out troubling pests or threatening diseases as they are identified.
At Happy Tree our pest control service addresses all types of bacterial and fungal infections and a wide variety of insect infestations common to the residential or commercial landscape. We utilize all of the most innovative approaches to pest control, including injections and drenches wherever possible to minimize the environmental effects common with aerial spraying. Many of our pest control efforts go toward maintaining the vigor of plants and trees through the use of soil amendments and fertilizers. Often infestations by pests and pathogens can be avoided by the use of a preemptive nutritional program.
Some of the most common pests and pathogens are:
Bagworms often appear as small cones on the plants on which they feed. They spin silken bags around themselves, to which they attach pieces of the specific host plant that they are consuming for camouflage. Full grown, they can measure nearly two inches in length, though while young they can go nearly unseen. The females lay their eggs in fall, and the eggs hatch the following spring.
Bagworms should be controlled as soon as they are noticed, as large numbers can quickly defoliate a tree. An insecticide spray is recommended in early June through July when they are most ravenous. If bagworm infestations are an annual problem, a systemic, water-soluble insecticide can be applied in late February and March to protect plants throughout the year. Their ‘body protective’ bags remain on the host plant until they are removed or they degrade. Some control can be achieved by handpicking these bags from plants in late summer or over the winter, since many eggs sometimes remain in the protective bags. Preferred host plants are arborvitae, juniper, pine, spruce, maple, locust, honey locust, and sycamore trees.
Eastern Tent Caterpillars emerge from a shiny dark egg mass that encircles the fine twigs on the trees upon which they feed. They build silken tents on branches of host plants, where they reside while consuming the foliage. The appearance of webbing (tents) may be the first evidence of the tent caterpillar’s coming feeding frenzy. This tent will quickly expand as the growth of these voracious caterpillars increases. Full-grown larvae are hairy and black with white stripes on their backs. Narrow brown and yellow lines and a row of blue spots are visible along their sides.
Wiping the webs from the tree and immersing them in a 10% alcohol solution, if possible, attains early control. Otherwise they should be destroyed as soon as they are noticed, as numbers can quickly defoliate a tree. Systemic control in early spring can be used to control this aggressive feeding insect. Insecticide sprays may be necessary to control these pests. Preferred host plants are cherry, crabapple, and apple trees.
Fall Webworms - Much like eastern tent caterpillars, the tents of the fall webworm are often visible before the pests can be readily seen. Fall webworms build silken webs on branches of host plants, where they reside while consuming foliage. Young larvae are pale yellow with two rows of black marks along their bodies. Full-grown larvae are green and covered in white hairs, which protrude from orange and black spots. They sport a yellow stripe along their sides.
Fall webworms are unsightly and can cause structural damage as a result of the wind stress created from their large webs. Their feeding cycle occurs at a time when glucose production is essentially completed and does not represent a major stress for trees. They can be controlled with aerial sprays or root drenching with water-soluble solutions. Their preferred host plants are walnut, hickory, birch, cherry, and crabapple trees.
Scale - There are many different types of scale insects that attack many different host plants. These pests have waxy, hardened shells, which protect them while feeding. Some scale feed on the undersides of leaves and needles, while others feed on twigs. Damage is first evidenced by the leaves or needles turning slightly yellow and falling prematurely. Weak host plants are the most vulnerable.
This pest should be controlled the first year it is noticed, as it can significantly weaken an infested host plant. A non-toxic dormant spray can be applied in late March to kill eggs and emerging larvae, or the host plant can be injected with insecticide capsules between spring and fall. Along with destroying this pest, an infested host plant should be reviewed, as it may need other supplemental care such as feeding or irrigating. Common infested host plants include spruce and pine, as well as poplar and magnolia.
Canker is a fungal pathogen. There are many different types of this fungus that attack different host plants. Some result in visible cankers. Cankers appear as open bark lesions, which vary vastly in size, eventually swell, and girdle infected portions of host plants. Weak host plants are the most vulnerable.
Infected branches should be removed and burned when possible, and infected host plants should be injected with fungicide capsules between spring and fall. Along with treatment of the fungus, an infected host plant should be reviewed further, as it may need other supplemental care such as feeding or irrigating. Common host plants include, but are not limited to azalea bushes and maple, willow, crabapple, and dogwood trees.
Verticillium Wilt is a soil-borne fungus. As a result of this vascular tissue disease, the leaves of infected trees are smaller, and their margins become brown. Branches on one side can suddenly die, and seed production can be greatly increased. The sapwood of infected host plants becomes visibly discolored with green to black streaks. Infected trees can die slowly over several years, or within a few weeks. Weak host plants are the most vulnerable.
Infected branches should be removed and burned when possible, and infected host plants should be injected with fungicide capsules between spring and fall. Along with treatment of the fungus, an infected host plant should be reviewed further, as it may need other supplemental care such as feeding or irrigating. The most common host plants are maple trees.
Bacterial Leaf Scorch (BLS) is a bacterial plant disease that affects a wide variety of trees, particularly those of the red oak family. The disease is caused by a bacterium that clogs the infected trees’ xylum and interferes with their ability to take up water. The first symptoms of this disease often appear in late spring or early autumn, and they often mimic the effects of heat stress or drought. Leaves usually exhibit a scorched or burned appearance, especially on the edges and between the veins, which progresses to twig and branch dieback.
While BLS is not a new disease, it has recently become epidemic in our area, and it has caused the death of countless majestic trees in a relatively short period of time. The most effective treatment currently available to combat BLS is trunk injections of antibiotics to suppress the bacterial agent and growth regulators to maximize the trees’ use of resources, combined with regular watering, nutritional support and specially timed pruning to remove dead and infected wood. In some cases it may also be beneficial to employ insect control mechanisms to combat insects such as leafhoppers and treehoppers that are known to transfer this bacterial agent from infected plants to healthy ones.
Because the early symptoms of BLS mimic other common stress agents in trees, laboratory confirmation of a diagnosis of BLS is highly recommended. Our technicians can retrieve samples and submit them for expert laboratory analysis.
Trees With Environmental Issues
There are an increasing number of trees with debilitating diseases and inherent structural problems. We at Happy Tree feel that it is important to provide a brief list to forewarn our clients of some of these problems.
- ash - emerald ash borers and ash yellows
- oaks - (particularly the red oak family) Bacterial Leaf Scorch
- American sycamore - persistent anthracnose infections
- white birch - pest heavy and chemical dependent
- little leaf lindens - Japanese beetle delight
- Bradford pear - poor structure and inferior crotch strength
- Douglas fir - needle cast and a host of spruce gall diseases
In the late spring and early summer, homeowners often notice large, black bees hovering around the outside of their homes. These are probably carpenter bees searching for mates and favorable sites to construct their nests. Male carpenter bees are quite aggressive, often hovering in front of people who are around the nests. The males are quite harmless, however, since they lack stingers. Female carpenter bees can inflict a painful sting but seldom will unless they are handled or molested.
Carpenter bees resemble bumblebees. Despite their similar appearance, the nesting habits of the two types of bees are quite different. Bumblebees usually nest in the ground whereas carpenter bees tunnel into wood to lay their eggs. Carpenter bees prefer to attack wood which is bare, weathered and unpainted. Therefore the best way to deter the bees is to paint all exposed wood surfaces.
Liquid sprays of carbaryl (Sevin), chlorpyrifos (Dursban), or a synthetic pyrethroid (e.g., permethrin or cyfluthrin) can be applied as a preventive to wood surfaces which are attracting bees. Residual effectiveness of these insecticides is often only 1 – 2 weeks, however, and the treatment may need to be repeated. Tunnels which have already been excavated are best treated by puffing an insecticidal dust (e.g., 5 percent carbaryl) into the nest opening. Leave the hole open for a few days after treatment to allow the bees to contact and distribute the insecticide throughout the nest galleries. Then plug the entrance hole with a piece of wooden dowel coated with carpenter’s glue, or wood putty.
(Courtesy of the University of Kentucky Cooperative Extension Service)
The Emerald Ash Borer (EAB) is an invasive beetle that destroys ash trees, and it has been detected for the first time in Butler County, Pennsylvania. The EAB is a wood-boring beetle native to China and eastern Asia that most likely arrived in North America hidden in wood packing materials. It was first detected in July 2002 in southeastern Michigan and neighboring Windsor, Ontario, Canada. The beetle has since been blamed for the death and decline of more than 20 million ash trees in Ohio, Indiana, Maryland, Virginia, and Illinois.
The European Hornet is the largest European eusocial wasp, commonly known as the “hornet”, and has a long seasonal life. This species is not particularly aggressive except when defending the nest, and care must be taken when in proximity, as the stings are quite painful. As with most stinging insects, they will sting in self-defense when grabbed or stepped on. These hornets have been reported to girdle twigs of numerous trees such as dogwood, birch, rhododendron and fruit trees, probably more for sap than wood fiber. They may build their nests in trees. Future queens abandon the nest to overwinter individually in sheltered areas such as under loose bark, in rotting stumps, or hollow trees. Large numbers of queens may be found using the same hibernation site.
See our Links to Resources & Newsletters for more information, or give us a call for a consultation.
Thousand Cankers Disease
Concerns: Dieback and mortality of eastern black walnut
A tiny bark beetle is creating numerous galleries beneath the bark of effected branches, resulting in fungal infection and canker formation. Both the fungus and the beetle only occur on walnut species. An infested tree usually dies within 3 years of initial symptoms. The earliest symptom is yellowing foliage that progresses rapidly to brown wilted foliage.
Juniper Tip Blight
Dieback on tips of many evergreens including (but not limited to) cedars, junipers and cypress. These plants if infected need 3 applications of copper based fungicide at 2-week intervals. Preferred time is May 1, May 15 and June 1.