Defending the Delicious

If you’re a fan of plants, you may not be a fan of deer eating them.

I enjoy deer watching... from a distance that is. A good fence makes great neighbors and it can certainly help a great garden.  however If you are like many of us who don't want the expense or incarcerated look and feel of living inside a fenced compound you do have options.

The best defense is a great offense and deer are complex creatures of habit. When they feel safe and find delicious food, they will include your trees shrubs and greenery on their daily wanderings. As with any Unwelcome guest making them feel more than a little uncomfortable speeds their departure and reduces the chance they will return.

Deer have a varied menu of trees shrubs and plants the will eat and in a pinch this grows to include normally unpalatable items like spruce, tree bark and wood.

These are listed in order of desperation and are not exclusive; they will eat whatever is available to survive.

They generally prefer lush energy rich plants like hosta or evergreens with softer needles like taxus or hemlock.

You can just plant trees and shrubs that are deer resistant but that leads to a dull landscape.

The best defense short of an 8 foot fence is a multi-pronged assault on all the deer's senses. Smell, taste and sound are three primary senses used by deer to navigate their way in the landscape. Sight, and particularly motion are also factors that influence a deer by making them feel less at ease. 

Change and motion in the landscape creates feelings   of unease and the potential for predators to sneak up on them well feeding makes the deer less likely to linger and sample your garden. 

There are many taste and smell deterrents available that use a variety of ingredients including blood, urine, garlic, rotten eggs and a variety of mouth burning spices and peppers. They all work to some extent, but deer, being creatures of habit will eventually  adjust  to the taste and smell and eat your trees and shrubs in spite of your repeated spraying. A change will do you good! Change up your spray by using a variety of different sprays. This reduces habituation and acts on a variety of senses. Deer don't like this unpleasant change. 

Blocking trails, and reducing bedding and birthing areas in your immediate hinterland will also take the game to a new level. Keep in mind that other people use trails before you pile brush or put log mats across them.  Placing a few brushy branch piles on sites that deer lay down to rest on is a sure way to keep them on the move,

If a doe does give birth near your garden the feeding pressure will be increased as the new mother will not travel far to feed while the fawns are small. She will eat a much greater variety of non-preferred foods while she nurses and stays close to the birthing area. 

Encouraging you dog to mark its territory at the boundary of your garden is also an effective deterrent. Motion sensing sprinklers, lights and other high tech gadgets are also effective as part of an overall program of wholesale unfriendliness.

Sound deterrents are useful as they not only startle the deer but create a sense of unease at the lack of ability to hear the approach of predators. 

As with all deterrents sound devices must change and have variability to prevent them from becoming routine and ignored. All this can seem like a lot of work and it can be, you have to keep in mind that your garden has to be peacefully and accessible. Thankfully our senses are much less keen than the average deer so we don't smell the repellents or hear the ultrasonic devices. There are companies that will provide a regular deer repellent spray program and this can be very effective as it takes the burden of scheduling off the home owners. Most of these programs change their formulas periodically to keep ahead of the deer. There are also companies that provide a dedicated deer deterrent program to take the entire process to a higher level while allowing you to plant what you want. 

ISA certified arborists are aware of what trees and shrubs are deer resistant in your landscape. Contact your land ISA Certified arborist to discuss your options for limiting deer damage on your landscape.

New Rust in Town

                                 photo TCC

For the Bradford pear the long reign as the most trouble free tree may have come to an end. Recent laboratory confirmed cases of Pear Trellis Rust  Gymnosporangium sabinae   have been located in the North Eastern United States . While it has been present in Southern Ontario since 2007 and  is a common disease in the Pacific North East and Europe it has not been discovered beyond those areas. Pears, up to this point, have been free from most pests and had only their poor structure to cause problems in the landscape.  

Like most rusts, Pear Trellis Rust requires two distinct hosts at different times of the year. The summer host, the pear, is the most disfigured by the rust and may become completely defoliated if the outbreak is severe. Repeated unchecked out breaks could result in die back and mortality. The winter host, the juniper, is much less severely affected. The disease over winters as a gall on the juniper erupting in the spring with bright orange gelatinous fruiting structures called telia. These structures produce spores that are blow in the wind to the nearest pear. Under ideal conditions these can travel up to four miles.  The effect on landscape trees is dramatic. After the initial infection causing reddish orange blotches on the leaves the leaves turn brown they will fall from the tree throughout the growing season. On fruit trees it will damage a crop in short order. While the life-cycle of this disease is complicated, its unsightly effect on pears is simply awful.

All pears appear to be susceptible to varying degrees. Cultural controls like removing junipers from the area are not realistic given the close proximity of the two hosts in a typical landscape. Even if you were able to remove your junipers the possibility of there not being one in the area to act as a secondary host is remote. As this is a newly discovered disease treatment plans are still in the developmental stage and no fungicides are currently labeled to control this disease. One suspects that in time a treatment regime similar to apple rust will emerge and prove effective in controlling this new found nemesis of pears.

Take the time to contact your ISA Certified Arborist today and have your pears accessed for the potential impact of Pear Trellis Rust. Panic is pointless, preparation is priceless.

Emerald Ash Borer Update 2012

   photo USDA                                                                     

Recent information has confirmed that Emerald Ash Borer has been found in Northern Dutchess County in South Eastern New York. Though not unexpected, it is a milestone to have confirmed its presence this side of the Hudson River.

Do you have a plan in place to protect your valuable Ash trees? Treating your Ash trees before this bug arrives has proven effective in protecting Ash trees from this deadly pest.

Emerald Ash Borer (Agrilus planipennis) was discovered in the Detroit region in 2002 but was likely established in that area in the mid 1990's. This small brilliantly green insect is from China, where it is a minor forest insect living on weakened Ash trees in its native forests. American Ash trees have no natural resistance and are excellent hosts to this pest. Once infested with this pest Ash trees decline and eventually die in 2 to 3 years. Small or stressed trees may die in one season. One mode of transport this beetle shares with other destructive pests is its ability to spread by hitchhiking on firewood.  Quarantines prohibiting the movement of firewood and raw wood products are in place or will be in place in many areas by years end. Efforts to eradicate the pest have been largely unsuccessful, leading one official to describe it as “cutting a hole in a doughnut". The beetles have often spread beyond the site of initial infestation by the time they are detected and treated.  Efforts are taking place to look for naturally resistant selections of Ash as well as locate natural predators that may reduce Emerald Ash Borer's destructive abilities. What can you as a home owner do to be prepared for this pest? If it has been detected in your area you will need to protect Ash trees you want to preserve.

First you will need to assess if you have Ash trees on your property and what the appropriate action you should take. If you have Ash trees and want to protect them, you should maintain the vigor of those trees with appropriate cultural measures. These may include fertilization, root stimulants and mulching. Once EAB is close to your area, there are proven systemic treatments that can prevent infestation by EAB. Preparation and prevention are your best defenses against Emerald Ash Borer damage. The chart below estimates the risk to your ash trees posed by EAB and can be described as follows:

0-5 miles from a known EAB site-                  Extreme Risk,

5-10 miles from an EAB site                           High Risk,

10 miles and greater from an EAB site            Elevated Risk.

If you are in an area that is at elevated risk you should be developing a plan with the help of your ISA Certified Arborist. Take the time to contact your ISA Certified Arborist today and have your property accessed for the potential impact of Emerald Ash Borer. Panic is pointless, preparation is priceless.

Cedar Apple Rust

                                                                               PHOTO TCC

Cedar-Apple Rust, caused by the fungal disease, Gymnosporangium juniperi-virginianae is another serious and disfiguring disease of ornamental and fruit apples. Rust fungi are evolved complex organisms that require two hosts to complete their life cycle.

The first host of this disease is Eastern red cedar, Juniperus virginiana,where the rust forms ball like structures with fungal telial horns that forcibly eject the spores that spread the disease to apples. Although these bright orange horned goo balls are quite alarming they are usually not noticed on the juniper or mistaken for fruit or cones. Once the spores from the juniper travel to the leaves of apples the real unsightly damage occurs. 

On apples the spores germinate and after a week or two cause orange pustules on the leaves of susceptible apples. Rainy wet weather in the spring is ideal for the germination on junipers and the spread and infection to apples.

Once in the apple leaf, given a short period of wet weather, the leaf lesions form fruiting structures in mid to late summer and re-infect the juniper host where the disease over winters. 

Cultural control, includes removal of junipers in the vicinity of apples as well as planting disease resistant varieties of apples. Avoiding mass plantings of apples and junipers in landscapes reduces the amount of disease inoculum and the potential for severe outbreaks.

There are a number of fungicides that are labeled for control of Cedar-Apple Rust. Typically they require several applications starting at bud break and continuing every two weeks to get suitable control. Fungicides may also be applied to junipers in mid to late summer to reduce the back transmission from the apples to the junipers.

Your I.S.A. Certified Arborist is up to date on the latest research on Cedar Apple Rust and can help preserve your apple trees.

Scabs on Your Apple

                                          photo bwg

Apple scab, caused by the fungal disease, Venturia inaequalis is one of the most serious and disfiguring diseases of ornamental and fruit apples. Although the name implies it is limited to apples, this disease can be found on many members of the rose family. The hosts can include apples, hawthorns, fire thorns, cotoneasters, and pears.

The symptoms of this disease are typically olive brown lesions on the leaves and sometimes on new succulent shoots. The scabs are indistinct at the margins and if the infection is severe they may coalesce into larger patches. The patchy lesions can be found on flowers, fruit, leaves and twigs. The tree responds to this infection by prematurely dropping infected leaves.  Repeated severe infections can cause die back after several years.

The disease overwinters in dropped leaves and affected twigs remaining on the tree. Wet spring conditions spread spores and allow them to germinate on the leaves, initiating new infections. The warmer the temperature, the shorter the amount of time it takes to initiate and infection. The peak period of infection occurs when the trees are starting to flower and continues until full bloom. Secondary infections will occur throughout the spring and summer when conditions are wet for long periods of time.

Some cultural control, including disposal of diseased leaves and twigs away from infected trees as well as the removal of all leaves in the fall will help to reduce the intensity of future infections. Planting disease resistant varieties and avoiding mass plantings also reduce the amount of disease inoculum and the potential for sever outbreaks.

There are a number of broad spectrum fungicides that are labeled for control of apple scab. Typically they require several applications starting at bud break and continuing every two weeks to get suitable control.

Your I.S.A. Certified Arborist is up to date on the latest research and can help preserve your apple trees.

Dutch Elm Disease a 1% Chance

                                         PHOTO BG

May 18, 2012

Every year at this time I bring attention to a tree disease that rewrote the book on urban forestry. Dutch Elm Disease is a fungal disease that, after decimating the elm forests of Europe early in the last century, was discovered in New York in the 1930s and has since crossed the continent. Described as 99% fatal to Ulmus americana, the American elm tree,.

Rapid growth and the ability to survive tough urban conditions are two of the characteristics that made American elms the go to tree for urban settings. Graceful vase like shapes lent themselves well to over street canopies and spectacular alles.

The only major drawback was its inability to survive the introduced fungal pathogen Ophistoma ulmi. This disease combined with the presence of a previously harmless bark beetle, created the perfect conditions for a country wide epidemic.

D.E.D. moved at a rapid pace, its sticky spores clinging to the bodies of both native and introduced elm bark beetles. This combined with people moving beetles and diseased firewood spread D.E.D throughout most of the native range of this stately, street tree

With such a high mortality rate there were many who predicted the eventual extinction of the American elm. However, there was right from the beginning tiny numbers of trees that, in spite of being in the middle of epidemic numbers of dead and dying trees, and plagued by hordes of bark beetles, survived,  continuing to grow and prosper.

There have been a number of programs funded and promoted by governments of Canada and the United States that have brought forward many potentially resistant examples of American elm. Through rigorous testing some are proving to be very resistant to D.E.D.

American efforts have resulted in American elm varieties like “ Princeton”, “Valley Forge” and “ Deleware” all of which have been shown to have some resistance to D.E.D. Canadian efforts to date have resulted in several trees of note, “ Brandon” an American elm and Jacan a Japanese elm pioneered by Dr. Wilbur Ronald formerly from Agriculture Canada’s Morden, Manitoba facility. This later selection is in fact growing in Brandon, Manitoba, on 10^th St. and on Pacific Ave. at 15^th St. Jacan does not have the characteristic vase like shape but has proven to be an excellent tree in other respects.

As we move forward in an age of cloning and micro propagation, efforts in Guelph, Ontario spear headed by Dr. Praveen Saxena, have resulted in the ability to mass produce resistant trees. This greatly increases the efforts to grow and test resistant varieties as well as producing them for introduction. With so many skilled and dedicated people working to find resistant American elms, one can’t help but have hope that from the thin numbers of survivors a new generation of elms will emerge and take their place on our city streets

Your I.S.A. Certified Arborist is up to date on the latest research and can help preserve your elm trees.

The Good Scout

In our previous article we discussed the history of pest management on landscapes and how it has evolved over time into I.P.M. Integrated pest management is the combination of cultural controls, like pruning and fertilization, with tree pest and disease control when necessary. This may sound contradictory but it is not, not all pests are at levels that impact the tree and not all diseases significantly impact the health of the plant or its utility in the landscape. Knowing the level of insect and disease pressure on a plant is complicated but always starts with identification. Both the plant and the problem must be correctly identified before the extent of the problem and the necessity of treatment are determined.

The key to identification is having a good scout, you must walk the property identify the trees and shrubs present and know the likely insects and diseases that may impact the landscape. Knowing each and every plant and disease is not possible as insects, diseases and the palate of plants in the landscape are infinitely variable.  Well, we as tree people and gardeners would like to think so, but sadly the variability is somewhat limited.

The scouted landscape patrol puts a qualified technician on your property armed with the tools of his trade, a keen knowledge of plants and there problems, and a variety of solutions to any issues he may encounter. Once the property has been scouted and the pest and disease problems have been recorded on a form or journal, the specialist goes to work correcting them. This may take the form of a spray or root zone injection or it could be a simple as cutting a nest of ugly caterpillars from your cherry tree and correctly disposing of them. Additional cultural treatments could include the removal of a circled root that threatens to strangle your maple or a suggestion that you relocate a sun loving lilac to a spot that is more open. Given the history of the property, kept in the treatment journal or in a file where the scouting reports are saved, the specialist may perform proactive preventative treatments. This may prevent issues that will occur several seasons in the future. For example, spider mites may be controlled in the spring when their population is low and before they cause premature defoliation of your burning bush in the fall. A simple application of horticultural oil at the right time on the right plant can prevent failures in the landscape in the future. By correctly limiting the amount and timing of applications you limit the number of applications that are necessary to catch up later. Reducing the extent and number of applications in your landscape is not only environmentally sound it’s economically sensible.

 Your I.S.A. Certified Arborist is up to date on the latest research and can plan and execute your scouted plant health care program with modern scientific techniques.