Be on the lookout for these pests on your trees and shrubs this summer
This growing season our arborists have been seeing a lot of trees and shrubs. As we visit from property to property we start to see patterns in regards to insects and diseases that are affecting trees and shrubs. Every growing season is a little bit different, with fluctuations in moisture and temperature playing big roles in insect and disease outbreaks. Some problems we see are largely the usually suspects that we see time and time again, and others are relatively new pests that are attacking our trees and shrubs for the first time.
Here are some insects and diseases to be aware of that the Hoppe Tree Service arborists are seeing having an effect on trees and shrubs in the Milwaukee area this year:
Emerald ash borer- Emerald ash borer is now becoming widespread in most Milwaukee area. This invasive insect attacks all species of ash trees and causes damage by burrowing into the trunk and feeding on the cambium tissues that bring water and nutrients through the tree. Protection treatments are available and work best for healthy trees. Treatment consists of a trunk injection around the base of the tree. Treatment dosage lasts for 2 years. Trees experiencing more than 25-33% canopy loss are probably too far gone to treat. If you want to save an ash tree and haven’t treated yet, now is probably the time.
Apple scab- heavy rains during spring has caused one of the worst apple scab disease years in memory. If you are experiencing black spots and discoloration on leaves, along with early leaf drop on your crab trees it is most likely apple scab disease. Pruning the tree to increase air flow throughout the canopy, along with fungicide applications to the leaf surfaces are the most effective methods of minimizing apple scab. There are numerous varieties of crab apple trees and susceptibility to the apple scab fungus varies depending upon the variety.
Boxwood leaf miner- Boxwood bushes are valued for their dense evergreen foliage and ability to be low maintenance plants. Unfortunately this spring we are seeing more boxwood leaf miner than other before. The leaf minor larvae feed between the upper and lower parts of the leaf, causing blisters on the underside of the leaf. The leaves infested by this pest become yellow and smaller than a normal leaf. When the plant is severely infested, it appears completely unhealthy.
Silver maple anthracnose- We’ve gotten a lot of calls regarding black spots and legions on silver maple leafs. This problem is called anthracnose and even though it can look quite troubling it seldom causes real health issues for the tree. The wet weather this spring has caused this disease to be rampant on many silver maples. As with most fungal diseases, the most affected parts of the tree are the lower branches which are more shaded, with less air flow. Typically treatment is not needed. The best course of action is proper pruning to increase air flow through the tree, along with raking up of fallen leaves so fungal spores do not re-infect the tree.
Viburnum leaf beetle- This tenacious feeder of viburnum bushes is a relatively new insect pest in the Milwaukee area. This beetle can defoliate a viburnum bush rapidly. The larvae can skeletonize young leaves by June. This is the first sign of an infestation. Emerging adults continue feeding on viburnum. Plants that have been defoliated for two or three consecutive years may die. Highly susceptible viburnum species include Arrowwood Viburnum and high bush cranberry. Chemical treatments can control this pest and are best applied as soon as damage is noted.
Written by: August Hoppe
Certified Arborist WI-0477A
Hoppe Tree Service
Oh, Those Beautiful Crabapple Trees
Do you have a crabapple tree in your yard? Well, NOW is the time to take care of it. We receive many phone calls in the mid to late summer about crabapple trees. The conversations all seem to have the same start; “My crabapple tree looked so nice this spring and now it looks terrible. Why is that and what can be done to help it?” The tree has a fungal disease called scab. This is a potentially serious fungal disease of ornamental and fruit trees in the rose family. Trees that are most commonly and severely affected include crabapple, hawthorn, mountain ash, apple and pear. This disease is most severe in years with cool, wet weather, as the buds and blossoms are opening up. How is this spring adding up? It seems pretty cool and wet to me.
You will first notice scab on the upper leaf surface, as well as on the fruits. These lesions can be small, the size of a pinhead or as large as one inch in diameter. When the disease is severe, lesions can merge and cover a large portion of the leaf or fruit surface, defoliation of the tree will then follow.
The good news is that this disease can be controlled and if your tree is taken care of the leaves will stay on and will even have fall color. While many trunk and soil treatments are in testing stages, none seem to be a viable option at this point. Some trunk injections look promising; however drilling small holes into the trunk of a tree on an annual basis is not a good practice. As with most chemical products today, they only will last 7-10 days and then not be effective anymore. Thus, a program of 3 foliar sprays in the spring and early summer is the best approach. The timing of these applications is of utmost importance or they will not work. The new chemistry of the products we use provides effective control of an infection that occurred up to 10 days ago, and then 7-10 days forward. To cover our cool, damp springs, the 3 applications work great, and will aid the tree in holding the leaves all summer and into the fall. Proper thinning is also a great help in the control of this disease. If your tree is overcrowded in the canopy, the leaves will remain damp and this will accelerate the scab disease. I would suggest waiting until after flowering for any pruning of your crabapple.
If you can remember back to last summer, and if your crabapple tree looked sickly, NOW is the time to take care of it. By the time you begin to see the lesions it will be too late for this season. With the proper care, your tree should provide beauty to your yard all summer and even in the fall.
If you have additional questions, would like help or information on tree care, please contact a professional. Certified arborists must follow stringent safety and performance standards, are required to have insurance, and have a trained and professional staff that is dedicated to ethics and quality in business practices.
Written by Bob Gluck
Certified Arborist WI-0116A
Hoppe Tree Service
Best to request your trees early!
We are very fortunate in Wisconsin that we have easy access to most things we want and need. We can go to the local store and buy bananas, avocado, and a pineapple, and make an awesome smoothie. Until recently it would be crazy to think we would always have access to these items considering none of them are grown near here. Have you ever gone to the store and expected an ingredient but it was all gone or temporarily unavailable? I will bet you have. When this happens we might become upset or disappointed that we don’t have everything we need to complete our meal now. We became accustomed to the availability and now we have to wait. What does any of this have to do with trees?
Trees are a crop too. They are planted, cultivated, grown, shipped, and sold. Like other crops their availability is subject to many factors including supply and demand, economic pressure, workforce availability, etc. Unlike other crops trees are not ready for market in one year’s time. Trees take many years to grow and be available for market. The result is then if ever there is a problem in the process of producing trees the ramifications can be felt for a long time. There have been several problems in the nursery business in the recent past that is now leading to a nationwide shortage of available plants. During the recession, the demand for trees slowed; so then did the nursery’s ability to put new plants in the ground. Producers of plant related items, such as bags, containers, baskets, also reduced their production. Unemployment and wage disparities created a skilled labor shortage. Some small businesses didn’t survive. Now that we are out of the recession we continue to deal with the problems created by it. But wait there is more. Emerald ash borer and other recent increased tree disease problems have created a huge demand for new trees while limiting the types of trees we can plant. Both municipalities and private land owners are having to replace trees at very high quantities. The sum of the problem is then that we have a greater demand than our local nurseries can supply. All is not lost however. New plant production is ramping up, and the economy is still looking strong, but because trees take many years to grow, this will all take time.
Every year our staff receives a list from the nurseries with available pants (a grocery list of sorts). When we work with home and business owners on new tree plantings we reference the available trees that year and find a plant that fits your location, growing condition, and desired characteristics. This helps you get the right plant for your home or business. Unfortunately after the desired plant is identified the store might be out of supply because of the above mentioned problems. We have seen this now for several years.
The solution to out of stock plants is get your trees early. If you think you might want a tree replaced or planted in sometime this year let us get it ordered now. Spring offers the best selection and highest likelihood of availability. We don’t want to make compromises on the right tree for you. If you need pineapple for your recipe you don’t want to substitute a lemon (pun intended). Please take this into consideration and get your planting requests in early. If you wait too long the store might just be out of what you want.
John Wayne Farber
Board Certified Master Arborist WI-0877A
Hoppe Tree Service
Spring Tree Forecast
As we move out of the winter season and into spring, it is important to understand how the changing weather affects your trees and landscape. There are many actions we can take to give our plants the best possible chances for survival, but Mother Nature is the one who is really in charge. Per the Old Farmer’s Almanac, the weather conditions for spring 2017 are predicted to be cool and wet. This forecast, piggybacking off a relatively mild winter, is setting up a season that could be quite favorable for insects and diseases.
Overwintering insects, like boring beetles, gypsy moth, and scale insects, have higher survival rates when winter temperatures remain above extreme cold (extreme cold is defined as temperatures below 20°F for more than 14 days in a row). These insects will overwinter in loose bark, tree cavities, and in the top layer of soil. Our SE Wisconsin winter did not see these kinds of temperature extremes this year which means overwintering insects can be expected to survive in above-normal populations.
Fungal diseases, such as Apple Scab, Rust, and Powdery Mildew, can also survive mild winters better than winters with extreme cold temperatures. Fungal pathogens also spread faster and more vigorously when spring conditions are cool and wet.
Because the 2016-2017 winter season was mild (average temperature: 29.7 °F, National Weather Service), we need to have a good plan for protecting our trees and landscapes for the 2017 growing season. Choosing the right plant for the right location is very important; the plant’s native range, the landscape’s soil conditions, and sunlight availability all affect a plant’s chances of survival. A tree must have adequate water and nutrients as well; fertilization and regular watering practices can help promote tree health. Remember that a healthy tree has a better chance of combating insects and diseases. Routine inspection from an ISA Certified Arborist can help to develop a plant health care program to maintain and improve the health and quality of your landscape. If you have any questions, contact your ISA certified arborist today.
Written by Tony Seidl
ISA Certified Arborist NY 5908-A
Hoppe Tree Service Operations Manager–South Division
Wood Decay in Trees
Wood decay is one of the most common problems in urban trees, and because decayed wood could threaten people or property, it is one of the most serious. The presence of a conk or a mushroom on a living tree is a positive indicator of decay, and therefore represents an increased likelihood for a tree or its parts to break or fail. Some fungi will decay the wood faster than others, and some species of trees rot faster than others. It is possible to generalize about the amount of wood decay when certain wood decay fungi are found fruiting on a tree. Decay caused by some fungi is usually limited in extent, whereas when others spread it can mean extensive decay. Decay of living trees is a disease, and therefore spreads. Depending on the decay fungus present, and tree health, the amount of decay may increase to a point where the tree may become hazardous. Most decay in urban trees is found without the presence of any wood decay fruiting structures. In the absence of fruiting bodies, we rely on other indicators to warn us of the presence of internal decay. These signs, cavities, carpenter ants, cracks, stem or trunk swellings, seams, and others suggest decay is present but usually do not indicate the extent.
Common Wood Decay Fungi:
Ganoderma applanatum, Artist’s conk
Common hosts - Maples, oaks, most hardwoods
Habitat - At the base or trunk of living trees
Mode of action - An aggressive decay fungus that decays heartwood and can kill and decay sapwood
Notes - Almost always associated with extensive internal decay
Polyprus squamosus, Dryad’s Saddle
Common hosts - Maples, elms, horsechestnut, and most hardwoods
Habitat - Usually from old wounds or old pruning sites on stems and larger branches
Mode of action - Slow progressing white rot
Notes - Decay is usually restricted to the area around the wound and fruiting body, seldom a cause for removal, but branches may have be tested for decay
Schizophyllum commune, Split gill fungus
Common hosts - Maples, lindens, crabapples, most hardwoods
Habitat - On wounds and dead areas of bark and cambium on the trunk or larger branches
Mode of action - Slow sap rot and cambium killer on weakened trees
Notes - Common on trees that have thin bark that have sun scald or that have done poorly after transplanting, once established on wounded tissues, it can also attack healthy bark and cambium adjacent to infected tissues.
What should you do if your trees have fungi fruiting bodies?
Property owners and managers should work with a certified arborist to develop an annual inspection and maintenance plan for the trees that will alert the property owner to structurally unstable trees and set forth how they will be dealt with! This forward-looking planning can avoid damage to people and property.
Board Certified Master Arborist WI-0556B
Hoppe Tree Service