What is Oak Wilt?
Oak Wilt is a serious and in most cases deadly vascular disease that attacks the root system of Oak trees. Well, that's the short answer anyway. But, we are all about information, so here comes all of the juicy details about it! According to our friends over at The Department of Plant Pathology at The Ohio State University, The fungal pathogen "Bretziella fagacerarum (formerly Ceratocystis fagacerarum), is known to occur in North America, but its origin is currently unknown. The pathogen is distributed throughout the Midwest and Texas." However, "over the years, and with variable frequency, it has been reported from the majority of the 88 Ohio counties". So, be sure to read this very carefully. As an Ohioan, your oaks could be at risk, if not handled properly and by professionals like us!
What does that Pathogen even do?
Well, the fungus grows into and throughout the sap wood (otherwise known as the "water conductive tissues") of the host. That fungus then plugs up vessels with its own body and spores. It then causes a defensive reaction by the tree itself to stop the fungal spread by plugging up its own vessels. Much like the human body when it comes to fighting off infection. Fascinating stuff, huh?!? When this happens, it interferes the water uptake which then causes "wilting syndrome" which most often will result in the death of the tree.
Which oak trees are susceptible to Oak Wilt?
Actually, ALL Oaks can be susceptible to oak wilt. Oaks that belong to the Red-Black Oak Group (this would include: black, blackjack, pin, northern and southern red, scarlet, shingle and shumard oaks) are the group that is most susceptible and often die within weeks of the start of this infection. Oaks that belong in the White Group (this would include: bur, chinquapin, post, swamp white and white oaks) are quite a bit more tolerant than their counterparts in the Red-Black Group and might very well survive for 1+ years but still exhibit declination.
How do we diagnose the symptoms of Oak Wilt?
There are several measures taken to diagnose Oak Wilt. Including, but not limited to:
*Leaves begin producing "flags", which is the withering of the leaves beginning in the upper canopy , causing portions of the crown or branches turning a reddish-brown color.
*With Red Oaks, those leaves will generally start showing yellowing or browning of the leaf margins
*With White Oaks, they typically show rather nondescript symptoms
*Live Oaks in the southern portions of the United States typically show those characteristic dead areas right along those leaf veins. They will then continue to overtake until the whole leaf becomes brown. Eventually, the leaves just simply fall from the tree. One important thing to remember is that if the infection occurs in the late spring, trees will begin displaying these symptoms of wilting and discoloration in mid to late summer when there is decreased rain and increased transpiration demand (a direct result of a water deficit).
*Aside from appearance, there are other defining characteristics to watch for when it comes to identifying Oak Wilt. With Red Oaks (but not with White Oaks), there are spore-bearing fungal mats under the desiccating bark. These mats crack the bark wide open with pressure pads to facilitate dissemination of the pathogen. However, Sapwood streaking is also good BUT insufficient. According to our friends at The Ohio State University C. Wayne Ellet Plan and Pest Diagnostic Clinic, conclusive diagnosis can only be made in specialized labs, such as theirs.
What is the Disease Cycle and any conditions that may favor this disease?
You must first understand your oaks and their cycle. The pathogen can spread from diseased trees to healthy ones one of two ways: overland and underground. Overland spread is mostly via sap feeding (also known as "picnic") beetles. There is some evidence that oak bark beetles could be involved too. Nitidulids (Beetles) are attracted by chemicals coming from the fungal mats, as described above. Once it is on the mats, the beetles pick up fungal spores and then travel with them. Sometimes, that travel can be upward of a few miles. They are attracted to the scent of fresh sap. This results in new infections, which then closes the overland cycle. While it's easy to blame the beetles, actually, 90% of new infections occur between neighboring trees through their roots. What happens with this, is that the fungus grows down the trunk and into the root system of diseased trees then into the healthy trees roots. Once inside the new healthy tree, the pathogen will continue to grow throughout the vascular system to the point of infecting surrounding trees that happen to cross over their root systems.
How do we control it?
The BEST way to control Oak Wilt is through preventative measures that interrupt the disease cycle. When it comes to preventing Overland Spread- trees should not be wounded (trimmed, removed, etc) between April 15th and July 1st. An even more aggressive approach would be to avoid wounds throughout the growing season which runs from April 15th- October 1st. If pruning is absolutely necessary (which in some cases, it is, due to a tree being too close to your home or vehicles that carry the potential of being dangerous or damaging to ones property) then it is absolutely imperative that you dress the wounds. This can be done with latex paint or similar sealant. This will slow wound healing. BUT, it will also deter beetles from landing on the wounds and causing issues.
When it comes to preventing Underground Spread- There is a higher likelihood that underground spread will occur before overland does. Therefore, controlling the tree-to-tree transmission is much more important. With this, in order to disrupt this process, you must physically sever actual or potential root contacts between healthy and diseased trees. This is done by trenching or cutting the soil with a trencher or vibratory plow. Preferably, the vibratory plow. Given the depth of oak root systems, it is advised to use at least a 5 foot blade to accomplish this task. It is very important to note that trenching must always be done BEFORE diseased or dead trees are cut down so that you can avoid sudden water tension imbalances that may suck up fungal material from the infected trees to the health trees that may share a common root system. Please only conduct trenching if trained to do so or hire a professional to accomplish such a task. An added layer of protection would ideally mean double trenching. This will define a buffer band between apparently healthy trees and diseased/uninfected trees. Please always remember to call before you begin to dig (trench) so that underground utility/gas lines are located prior to. This protects the person as well as the ability or inability to completely sever that graft. Don't forget sidewalks, walkways, driveways, streets, etc that may also have tree roots growing under them too! Lastly, even though there is no clear research/evidence released to our knowledge that the blade itself could spread the pathogen, it is still a good precautionary measure to spray the blade to runoff, between trenches and between plots with some sort of an antiseptic spray or liquid (such as Lysol or a 20% bleach solution).
How do we get rid of these dead and dying trees?
Once you have trenched the area, the diseased and dying trees need to removed immediately. When possible, you should cut them only to the point of leaving 2-4 inches of the stump exposed above ground. Diseased trees that have bark attached tightly, may produce or harbor fungal mats. Therefore, their disposal should be immediate. However, if bark has already come loose or off, no mats can be produced, therefore, your risk is decreased. Please know, there are strict restrictions when it comes to moving diseased wood out of state or country. You can either debark the tree mechanically or the timber can be sold to a sawmill for cutting and chipping. There are no studies currently that show that this disease can be transmitted to wood chips. Composting decreases the chance of the spread of the pathogen even greater, however. If the wood cannot be disposed of as the previous has mentioned, you can always cut and split it for firewood because this does not involve debarking. If you do decide to make firewood, there must be a period between cut and use where you will need to store the wood in a greenhouse-like environment, in order to ensure no continued or new pathogens develop. This can be achieved by using a clear tarp or black tarp free (it is suggested a 4 mil plastic tarp-clear or black) of holes and gaps and consistent with that of a greenhouse.
Special Thank you to our friends at The Ohio State University and Fred Baker for the fabulous visual aides used in this slideshow!
Let's talk Ornamental Disease!
(If you're fancy, call it "Rhizosphaera Needle Cast of Spruce")
Needle cast causes needles to turn brown (or, if in the case of the Colorado Blue Spruce, a purplish-brown) and shed from the trees prematurely. This disease can happen on any age and any part of these trees, but the disease often begins on trees at least 1 year or older and throughout several branches on the tree. The lower the branch, the higher the likelihood is that it will be impacted by this disease. This is mainly in part because the lower the branch, the more dense and shaded the foliage is. This causes decreased air flow and moisture locking in for longer periods of time as opposed to higher branches that have increased air flow and proper sun exposure. If conditions remain conducive for a number of years, the disease will eventually spread from the top to bottom, inside and out of that tree.
What Causes this disease?
Well, other than what has been already mentioned, fungal fruiting bodies containing spores called "Pycnidia" begin forming in rows when moisture is high during the spring time. Pycnidia when matured, present as brown/black spherical structures that are less than 0.1mm in diameter. These form in a more pore-like opening of the needles called "stomata" (stoma=singular). It will push through the stoma, thus causing the dislodgment of the stomatal plug, forming a white wax-like cap on the top. Magnifying glasses are often used to view rows of black pycnidia. These may or may not be capped white plugs.
When do the infected needles drop to the ground?
Typically between late spring and fall (usually around 12-15 months after the initial infection begins). An easy diagnosis with Spruces is they simply will not form new needles after the old ones drop off. When you see bare spots throughout your spruce, you more than likely are looking at the affects of this disease. That, and branches might actually begin to just fall off after 2-4 years of needle loss. Obviously, in the most severe circumstances, the entire tree will just die.
How does one manage their plants/trees in an effort to prevent disease?
Well, there are a few ways you as the consumer can guard yourself against this.
1. Always purchase your plants/trees pest & pathogen free from reputable sources.
2. Always inspect your plants/trees prior to purchase. Look for signs of wilting, discoloration and/or defoliated. Do not purchase anything with the mindset of "I can bring that clearance item back to life!"
3. If at all possible, purchase your trees and plants from local seed sources. They will be in better health overall, plus adapt better to your own local conditions. This will enable them to more than likely resist this disease!
4. Find the perfect spot!! Sometimes not all plants and trees can be planted in spots that YOU want them to be in! Avoid planting highly susceptible species where shady, humid, low and moisture ridden areas remain high for long periods of time throughout each day.
5. Plant them correctly! Give them space to grow! Think about the roots when they grow big and think about limb space where limbs would intermingle. These plants/trees don't stay small forever (like children), they grow and need room to be free! Also, don't plant young ones near old ones. The old ones could very well be harboring pathogens that have just not started showing signs yet!
6. When watering, don't take the easy way out when these plants/trees are youngsters! Their young, vulnerable foliage cannot handle being wet for prolonged periods of time. So nix the sprinklers or overhead irrigation systems in the beginning. Handle them with care and water them by hand! And do so in the early morning so that they have enough to dry throughout the day.
7. Don't stress them out! Meaning, don't fertilize woody plants. Always water throughout dry periods (drought). Keep vegetation and weeds away from their bases. This will encourage good air circulation and lighter penetration to the lower branches.
FUN FACT: Did you know that Nurseries and Plantations are required to quarantine incoming plants and inspect each one for signs and symptoms of disease? AND, if they find anything wrong they are to remove it from inventory and dispose of or return it to it's original source! Next time you are shopping, ask them if they have quarantined their new arrivals and if so, for how long!
Scout it Out!
Always inspect your trees! Especially if they are over 5 or 10 years old! Break out that magnifying glass and look for those brown/black spots arranged in neat rows on your needles.
Here's a lil pro tip: If you don't immediately see pcynicidia, you can still test at home for it. Just place any suspicious needles in a plastic bag with a wet paper towel. Keep the bag somewhere that is room temperature. If the needle is positive for the disease, you will see pcynicidia develop in a day or two.
Cultural Control Practices
During more wet periods, don't conduct any pruning or shearing that might facilitate spore dispersal and infection.
Sterilize your pruning or shearing tools that you have used on known or even unknown infected trees/plants (you can use Lysol or even a 20% bleach mixture for this!)
For highly populated areas of trees, always dislodge and destroy any fallen needles that might collect in the crotches of branches and even those on the ground. Allowing them to accumulate can cause the needles to harbor large amounts of pathogen inoculum.
Applying fungicides containing the ingredient Chlorothalonil is effective. However, it could take years of treatment for the tree's appearance to improve. There are only two applications needed per year, when properly timed out. This practice would need to be for 2-3 consecutive years in order to get it under control. The first application should happen just after the bud breaks and new needles are half way elongated compared to the previous years needles. The second application should occur 3-4 weeks after round one has been done. Always read the directions on each fungicide for safety precautions, preparation, application, storage and disease development. And check with your local county or state extension specialist for an up-to-date list of registered fungicides that are available.
**If you are uncertain about what's happening with your spruces, you can always send a sample over to our friends at The Ohio State University C. Wayne Ellett Plant and Pest Diagnostic Center.
* Thousand Cankers Disease *
WATCH YOUR WALNUTS!
Susceptible Trees within the walnut family are:
* Black Walnut VERY susceptible!
*Northern California Walnut in the Intermediate susceptibility category
*Arizona Walnut is actually resistant
*Pecans are completely immune
So, what IS Thousand Cankers Disease ("TCD")?
TCD is a disease that can cause widespread mortality to walnut trees, especially in the western United States of America. It was first detected in Colorado when an overall general decline occurred in the early 2000's. Originally thought to be caused by a drought, but is now confirmed to be a fungus. This fungus is carried by an insect called the "walnut twig beetle" which greatly increases the chances of infection into walnuts! Since the 2000's, it is safe to say that TCD has been found throughout the western United States. In late 2012, the walnut twig beetle was found in Southwest Ohio in a baited trap. However, since 2016, the disease had not yet manifested itself in Ohio.
Eastern Black Walnut is particularly susceptible to TCD, so the discovery of TCD east of the Mississippi River does still pose a threat to black walnut survival. This is especially true here in Ohio, because of the oak and hickory forests. Both of which, eastern black walnuts are a member. In fact, oak and hickory forests make up for more than half of the forested land here in Ohio. Eastern black walnuts can also be found in both natural and urban landscapes. Eastern Black Walnuts trees are very important to our eco system. It is a versatile wood that can be used for wood products, such as veneer and lumber, nut production and more!
*Yellowing of the foliage
*Upper crown thinning
*Dying of twigs and branches
As this disease progresses (especially in the crowning) it is then preceded with a forming of several, small areas of dead/dying tissues underneath the outer bark of both branches and stems. This is also often times referred to as "cankers". This is the precise symptom that gives this dreadful disease its name.
As the fungal colonization continues to develop and spread, so do the cankers. Eventually, it starts to penetrate the inner bark and the wood. During the latest phase of this infection, you can expect for multiple cankers to coalesce. Eventually, the tree will sadly die.
How do we treat it?
Currently, to our knowledge, there is no known treatments for trees that are affected by this disease. So, one must just focus on disease prevention and sanitation. So here are a few things you can consider:
* Don't move firewood if you suspect that beetles may be present in the bark. Beetles are typically active between April and October and in 70-90 degree weather.
*Try to maintain overall tree health when going through dryer seasons or droughts. Avoid if at all possible, any damage to the tree.
*You can try in some cases to treat your area with insecticide sprays or soil injections. Please call a professional in these cases, just to avoid any unforeseen issues when the uses of chemicals.
*Check out your walnuts! Inspect them regularly! Look for the above symptoms.
*For most up-to-date information on TCD infestations, you can download a free app (for both Apple iOS & Android users) called "The Great Lakes Early Detection Network (also known as "GLEDN"). This is an interactive app that you can upload pictures and location information on trees that you may suspect as being exposed to this disease for its verifiers to confirm or deny! Please know, this app will collect your data that will then be added and used in the Early Detection and Distribution Mapping System!
White Pine Blister Rust (on Currants and Gooseberries)
When it comes to serious diseases of currants and gooseberries, white pine blister rust is not serious. However, it is very serious for White Pines. The reason for this, is because currants and gooseberries serve as an alternate host for the rust fungus that actually causes White Pine Blister Rust. It is just not a good idea to plant any currants or gooseberries in any area where white pine trees are planted because it could cause some serious losses in that area.
Which species are susceptible?
The most highly susceptible species are:
*North American White Pines
*Eastern White Pines
*Southwestern White Pines
*Western White Pines
*Black Currant (most susceptible to the Ribes species
White Pine Blister Rust actually causes most of its damage in the form of cankers that form on the branches of these pines. Those cankers are what will ultimately kill the entire tree.
There is actually some current case law on the books for the State of Ohio in regards to suppression and control of White Pine Blister Disease.
Ohio Law (Regulation AG-71-85.01) states the following:
1 (a): The European black currant, Ribes nigrum L. or any variety of this species is hereby declared to be a public nuisance, and it shall be unlawful for any person to possess, transport, plant, propagate, sell, or offer for sale, plants, roots, scions, seeds, or cuttings of these plants in this state.
2 (b): Recognized varieties, e.g., "Consort" produced by the hybridization of Ribes nigrum L. or a variety thereof with a resistant or immune species, known to be immune or highly resistant to the White Pine Blister fungus, (Cronartium ribicola, Fischer) are exempt from the restrictions imposed by paragraph 1(a) above.
Note: Ohio law does not prohibit the planting of red currants or gooseberries within the state.
What are the symptoms?
Well, symptoms vary on the species. For instance, on White Pines, symptoms include: dead branches, chlorotic foliage, girdling of branches caused by lesions that produce resin or a yellow, sticky fluid (otherwise known as spermagonia), those pesky cankers (this time around, they are diamond shaped cankers) surrounded by a band of yellowish- green looking infected bark to a light yellow-orangish aecia and ultimately, the death of the tree.
With Ribes, however, in the springtime, little yellowish spots become visible on the upper part of the leaves. On the opposite side (otherwise referred to as the underside) an orange-yellow, almost blister-like little fruiting bodies start to appear. By mid to late summer, a yellow/brown threadlike growth begins to develop on or near the infected spots on the leaves.
And don't think that bushes get off easy! They are susceptible to this and will show such by premature defoliation!
As with most of these diseases, White Pine Blister Rust is caused by none other than a fungus. This fungus called "Cronartium Ribicola" was first discovered in Europe in the early 20th Century! It has spread throughout the entire range of whites pines throughout North America. The life cycle for this disease takes between 3 and 6 years to complete. The initial infection for black currant bushes will typically occur in the spring time. The spores from this fungal disease travel on the wind stream for miles and miles.
Let's get this under control!
1. Remove them!
2. Replace them with only disease free varieties that are approved by the Ohio Department of Agriculture. Those can include: Consort, Crusader, Coronet, Lowes Auslese, Polar, Titania and Willoughby. Red currants and gooseberries are not affected by Ohio Law and are completely legal to plant.
*Currently, there are no known fungicides labels on currants and gooseberries for control of white pine blister rust.
Galls are plant structures that form as a result of arthropod feeding. This plant growth is abnormal and is stimulated by a combo of plant hormones and hormones that are introduced into the plant during arthropod feeding. How does the plant respond? By increasing the production of leaf tissue which then encloses the mite/insect. From there, they feed from within the gall.
On silver and red maples, the leaves will generally get covered by little wartlike structures that are red, small and round (typically between 1/6-1/8 inches in diameter). At first, galls start out green. However, they will quickly turn pink to red and then eventually will turn black. Sometimes, leaves will become so covered with the galls, that they eventually completely twist out of shape or even drop earlier than usual.
On a sugar maple, a different leaf gall is commonly found. This one is caused by the mite "Vasates aceriscrumena" (Riley). This gall is thin with elongated bladders rising from the upper surface of the leaf. These galls will rarely distort the leaf if only a few are present. However, if there is a larger amount on the leaves, it is noticeable and unsightly.
There is a maple gouty gall midge that only attacks the sugar maple and causes a thick pouch along all of the major veins of the lead. These galls can completely crumple the early leaves of maples and make them look as though they have been harmed by some sort of herbicide. These galls are caused by larvae from small, gnatlike midges.
Aside from the aesthetics and possible early leaf drop, this causes no real health threat to your maple trees. If going through a milder winter, damage can be excessive, however, affected trees can send out new leaves to replace all that were damaged by this.
You can help to control the spread by doing the following:
*Find varieties of maples that are resistant
* Prune your maples! This will help reduce the population of these mites
*DO NOT USE Dormant Oils!! These can actually cause more harm than good! If you are not sure if your maples are dormant, it can result in leaf and twig damage and even death of the tree!
*Insecticide and Miticide Sprays (might wanna call a professional!)
*Systemic Insecticides and Miticides (might wanna call a professional!)
Diplodia tip blight is one of the most visible diseases in the urban environment. In the Midwest, many of your common landscape pines is affected. Common landscape pines can include:
This is a fungus. It will more than likely attack mature trees that very well could already be under stress caused from drought, root restriction or other planting site issues. In younger trees, if the nursery is rapidly growing them for Christmas trees. This is a common disease throughout the Great Plains, Midwest, Northeast and California.
What are the signs and symptoms?
Well, it is characterized by the blight or the dieback of the tips of branches and can be relatively easily identified. This infection can happen year after year, until eventually, the tree will die. If you watch closely, you can often find that the disease will begin new shoots which causes the needles to turn completely brown before they are fully formed. A resin can also be found coming out of the infected new shoots. From that point, if left untreated or unaddressed, the infection will spread down the branch while the pathogen can also infect older tissues directly through wounds that are typically caused by insect activity or even hail. Older cones are susceptible to the disease and often support abundant fruiting on their scales. Occasionally, the fungus may form cankers on stems and branches of severely weakened trees.
One main way to determine if a tree is infected with Diplodia tip blight, is to look for the signs of the pathogen which will consist of:
*black , tiny fungal fruiting bodies that are formed on the surface of infected needles
*These are the source of the fungal spores that spread this disease
But how do we manage it?
*Avoid planting them in areas that are cool and wet weather in the spring, followed by drought or dry soil conditions throughout the remainder of the year
*water good throughout the dry periods of the year
*Pruning the trees
*Fungicides (partially can be controlled). New spring growth must be protected from bud swell to full candle elongation
*For higher value trees, call a professional so that they can mix the correct formula for your specific trees
Sudden Oak Death is a disease caused by a pathogen called "Phytophthora ramorum". It was first discovered in Central Coastal California in 1995. However, throughout the years, it has made its way across the United States via contaminated nursery stock from a west coast nursery back in 2004.
The pathogen, while having killed forests, may now only be limited by factors such as environment and therefore may never be able tp become established long enough to cause the disease to continue to have enough momentum to continue the spread.
A few characteristics of this pathogen can include:
*Reddish ooze coming from the bark/trunk of the tree
*Water soaked and necrotic lesions can appear on leaves/foliar host
The best way to prevent it would be to check regularly your Oaks and be sure to inspect any new oaks that you intend on planting! Ask your nursery/supplier of new oaks where they came from, should they be quarantined for any amount of time prior to planting and whether or not they have ever displayed any characteristics of the pathogen.
Dutch Elm Disease
Dutch Elm Disease ("DED") is one of the most destructive urban forest diseases. This one can primarily affect native American elm species, such as American, Slippery, Winged, September and Cedar. The species that are less affected are: Asiatic Elms, such as: Siberian, Japanese or Lacebark Elms. In fact, this disease is ultimately considered an issue for these species.
This disease was first introduced into America near Cleveland, Ohio in the 1930's and still continues to kill mature elms to this day. American Elm trees, which actually once dominated our urban landscapes as those beautiful shade trees we all know and love. Now, due to DED, they are no longer as prominent as they once were.
A good way to check for this is to exam for yellowing leaves on the tip of a branch and then turning brown and curling up. These symptomatic branches are called "flags" or "flagging". As the disease grows, more and more flags will appear until the whole crown is symptomatic. The most important part to remember is that Dutch Elm Disease CAN be treated if recognized early!
Beech Bark Disease
Beech Bark Disease ("BBD") is devastating to the American Beech tree. It caused by a combination of damage to the bark and vascular tissue in the tree by the beech scale insect. This is usually followed by an infection with a combination of several fungal species. It was first discovered in Nova Scotia in the 1890's and from there has been slowly progressing through the range of American Beech trees since then.
The scale insects will present as a "white wool" on the trunks of infested trees (either sporadically around it or over time, increasing in density until it is covered. Scale insects might be present for several years before the fungal infection occurs. You can manage Beech Bark Disease, but that requires control of or resistance to the beech scale. You can do so by scrubbing or brushing the insects off the tree or through applications of insecticides or insecticidal oils. Please read the instructions on any chemicals prior to usage.
This is also known as poplar leaf rust. It can affect various poplars, cottonwoods, aspens and willows in the United States and throughout the world. It is caused by several fungal pathogens in the genus.
Macrocyclic means that it produces five different types of spores at various times throughout its life cycle.
Heteroecious means that the fungus necessitates two hosts to complete its life cycle. Collectively, the list of alternate hosts is quite long and includes species of fir, hemlock, larch, pine and spruce.
This disease started in the United States in the early 20th century and today, it has widely impacted poplars in both eastern and western regions of the United States.
This disease can be managed effectively if the symptoms are recognized before a large outbreak occurs. To recognize the symptoms, look for yellow or brown or orange spots on the leaves. The orange resembles a rust color. You can manage it by doing the following:
*Removing the branches of the infected hosts
*Removing the entire host
*Removing fallen leaves of infected or susceptible trees
*Planting clones of resistant or tolerant individuals
*Using preventative fungicides such as Banner MAXX, Bayleton 25 WP and RosePride Funginex on high value trees
*Planting trees outside of the genus Populus and outside of the family Salicaceae
Strawberry Leaf Diseases
As the first leaves in early spring begin to unfold while continuing until dormancy in the late fall, fungal diseases such as this one will occur. They can cause a significant economic damage. The primary damage from leaf diseases is the loss of vigor through a reduced leaf area. If the outbreak becomes a great one, the plants will become weakened resulting in increased vulnerability to root diseases or even winter injury.
There are three major lead diseases that are caused by fungi.
Leaf Scorch consists of a number of small and irregular purplish spots or blotches that will develop on the upper surface of the leaves. The center of the blotches become brown. Blotches may coalesce until they nearly cover the leaflet, which then will turn a purplish to reddish to brown.
Leaf Spot is caused solely by a fungus. Symptoms will first appear as circular and with deep purple spots on the upper leaf surface. Eventually, the spots enlarge and the center turns grayish to white on older leaves and then light brown on the younger leaves. On fruit bearing trees/fruit, superficial black spots may form under moist weather conditions. The spots can form on ripe berries around groups of seeds. The spots are about 1/4 inch in diameter and there are usually only one or two spots per fruit. However, in some cases, fruits can become severely infected.
Leaf Blight is also caused by a fungus. Symptoms for this will with one to several circular reddish purple spots on only the leaflet. Spots will then begin to grow and eventually enlarge to a "V" shaped lesion that presents a brown inner and dark brown outer zone. These lesions will trail down the major veins and eventually will move inward. Eventually, the whole leaf itself may turn brown. In the most severest of cases, fruit trusses, petioles and stolons will become infected and cause the stem to girdle and die.
Control of Leaf Spot and leaf scorch by resistant varieties. There is nothing known to date to control leaf blight.
Bacterial Spot of Stone Fruits
The most affected are:
It is widespread throughout all fruit growing states that run east of the Rocky Mountains. Bacterial spots will then affect the leaves, twigs and fruit. In more severe cases, the infection results in reduced quality of the fruit and how much the tree will yield. Fruit infect is the most serious for trees that mature later than others. This disease is usually more severe where soil is light and low in fertility. The more vigorous of trees are usually a lot less susceptible to this diseases than neglected or devitalized trees.
In the leaves, you will notice spots that are irregular to angular and have a deep purplish to rust brown or black in color. In fruit, you will see small, round like olive-brown/black spots that form on the fruit. In most cases, the "skin" of the fruit is sunken and wet. Spots will eventually consumer the outside of the fruit and exude a yellowish gum after rainy periods.
On twigs, peaches specifically, two different cankers damage the twigs. These cankers are called "Spring Cankers" and the develop mainly on younger twigs that may have produced the previous summer. At first, they look water soaked and then will turn slightly darker as the leaves first appear. Eventually, it cover the twig and kill it.
On certain plums and apricots, twig cankers can continue to develop unto two and three year old twigs. In cases where the cankers are deep seeded, they can deform or even kill the twigs entirely.
Now, for the final act- Let's talk about Poison Ivy, Poison Oak and Poison Sumac!
They don't call this poison for nothin'! Perhaps we all have had the unfortunate encounter with one these! If you are one of the fortunate ones that doesn't have a crazy reaction to any of these types of plants (yes, they do exist out there!), consider yourself very fortunate! For those that have suffered through the aftermath of running into any of these poisons, we feel your pain!
There are ways to help yourself avoid them!
1. KNOW YOUR LEAF PATTERNS!!
2. Try not to touch or brush against these plants.
3. If doing yardwork, wear gloves and dress appropriately! Urushiol can actually stay on clothing.
4. If you have or suspect you have come into contact, do not wash your clothes with other clothes (splurge for the extra water and do the load individually and in hot water).
5. Do not take a bath! Take a shower instead! Did you know? Urushiol can stay in the tub water and cling to your body even when you get out of the tub!
6. Don't burn the plant. Burning can release the chemical in the smoke and it can come into contact with your skin that way.
Here's how you can treat it though! Yes! There is help!
1. If you know you have been exposed to urushiol, use rubbing alcohol on the exposed immediately. Once this comes in contact with your skin, it does penetrate very quickly. Try very hard not to return to the area where you were initially exposed until the next day. After using the rubbing alcohol and wash the exposed area with water.
As soon as possible, shower with warm water and soap or wash it with a special wash like ZanfelTM
Rashes or Blisters can begin to form, along with itching. This is all normal and will typically occur within 12-48 hours after initial contact with the plant. A common myth is that the oozing is contagious. It's not! The ooze does not contain urushiol. Therefore, you cannot spread it to other parts of your body. It is advised that you should not rub or scratch the blisters or rash. This is not for any other reason but to prevent infection should your hands or fingernails be dirty. The only places you will have a rash or blisters from contact with these plants is wherever the urushiol has touched your body. The rash will never spread itself. There is a possibility that you can get the rash in a new area if you handled contaminated items again. The reason that the rash, blisters and itch may appear at different times is because the poison may absorb at different rates of penetration, completely dependent upon which part of the body was exposed.
To ease itching, you can purchase over the counter ("OTC") antihistamines or hydrocortisones at your local pharmacy. In more severe cases, you can speak with your doctor who may prescribe an oral medication called "corticosteroid".
Some other OTC products to consider in assisting with drying up oozing blisters are:
*Aluminum hydroxide gel
*Avon Skin so Soft
Are you ready to take the quiz??
-TRUE OR FALSE-
#1 The poison urushiol can stay on your clothes if the clothes are not washed
#2 Burning poisonous plants destroys the urushiol
#3 A warm bath is a good way to get urushiol off of your skin
#4 Rubbing alcohol can be used to clean skin that has come into contact with a poisonous plant
#5 Once urushiol touches your body, it can spread to other parts
(We'll give you a hint: 1. True 2. False 3. False 4. True 5. False)