Midterm 1 study guide

Lab 2- Noninfectious disease  What are the major sources of these air pollutants? (S02, Fluorine, Ozone) o SO2 comes from industrial sources (coal combustion, smelters, refineries) o HF comes from aluminum/steel production, and phosphate based fertilizer o Ozone is phytochemically produced, No2 comes from automotive/industrial point sources and is altered in the atmosphere into O3  How can you differentiate the symptoms of frost injury, mineral deficiencies, herbicide damage, and air pollution damage? o There are several distinctive features that each of these factors showcase—  Frost injury: tip dieback on conifers  Mineral deficiencies can look a little different depending on the mineral missing, but examine for interveinal chlorosis, and growth stunting  Herbicide damage can be acute or chronic, and will look different in either case- acute will show bleached and burnt foliage, whereas chronic damage (likely from contamination of soil) will cause stunting and distorted growth  Air pollution damage will also differ slightly depending on the compound involved, but signs to look for are interveinal or marginal (around the edges) chlorosis, and needle dieback from the tips.  How can you differentiate between symptoms caused by fungi and those caused by abiotic diseases? How can you differentiate between insects and abiotic diseases? o Some of the ways to distinguish between abiotic factors and fungal pathogens are the patterns of damage- for example, a needle disease will manifest randomly across the needle of a conifer, whereas abiotic damage from say SO2 will look like dieback from the tip of the needle down.  What is the difference between sunscald and frost cracks? o Frost cracks form as long vertical openings on the sides of a tree’s bole- and will occur facing any direction. These cracks are deep, and will have a single layer of cambium growing over them to attempt to repair the bark. o Sunscald will typically form on the south side of a tree that is exposed to bright sun, and are the result of the cambium layer of the bark activating due to the warmth of the sun during the day, and then sudden cell damage from plunging nighttime temps. It can look like sunken, discolored bark, or many smaller cracks, possibly leading to the bark popping off the tree (can happen much later, in the summer).  How do you avoid winter injury on conifers?

o Sufficient fall watering o Wrapping them o Proper site selection  What can be done to avoid winter sunscald and frost cracks? o Fall watering o Light pruning to prevent direct sun  What trees are tolerant to salt injury? What trees are sensitive to injury? o Sensitive: White pines, maples, lindens o Tolerant: ginko, honey locust, aspen  How does salt damage trees? o Acute: spray films dry out exposed plant tissue, causing scorching and necrosis o Chronic: salt builds up in soils over time, first damage will manifest as marginal chlorosis/needle dieback from the tips, as well as inhibited nutrient and water uptake, as osmotic pressure is altered.  What conditions reduce iron uptake by the tree? o High soil pH (alkaline), compacted soils, nutrient deficient soils  What can be done to increase the uptake of iron? o Lowering soil pH, introducing chelated iron to the soil, or spraying/injecting trees with iron containing compounds  What tree species are most affected by this problem? o River birch, maples, white pine, oaks Lab 3- General Characteristics of fungi  What are the major differences among the Ascomycota, Deuteromycota and Basidiomycota? o Ascomycota are “cup fungi”; they can have both a sexual and asexual spore state. Their sexual spores are called ascospores, and are produced by structures called ascocarps (includes apothecium, cleistothecium, and perithecium). Their conidia (asexual spores) are frequently produced in a chain like shape.

o Sanitation  Are the powdery mildews of forest trees usually considered of economic importance? Why? o Less so, they rarely cause trees to die  What produces the black material that looks like tar spots on maple leaves? o Group of fungi called rhytisma, two native species, and one introduced that only impacts introduced Norway maples. The black material is the stroma tissue that houses the asci, the sexual spore stage.  How do species of Taphrina survive the winter? o Conidia (asexual state) overwinter in buds or twigs  What is the "general pattern of spread” within a tree infected with anthracnose? o It depends on the conditions- in a wet spring, it can resemble a wilt, with leaves emerging distorted. If infection does not occur until later in the season when the leaves are fully formed, the disease manifests as large blotches that will coalesce irrespective of leaf venation. Defoliation can occur. It moves from the bottom of the tree up.  On what species of oak do you most frequently find oak anthracnose? o White oak, not to be confused with oak blight, which more commonly impacts red oaks  What is the best control measure for anthracnose? o Sanitation of fallen leaves and increasing tree vigor.  What environmental conditions promote anthracnose? o Cool, wet springs  Can the fungus that causes anthracnose of maple infect oak or ash? o No, each fungi is species specific  What varieties of apple and crab apple are resistant to apple scab? o Many improved hybrids-  Apples:  Honeycrisp  Crabapples:  Adams, Adirondack, bob white, louisa, Prairie maid, royal beauty, calocarpa

Lab 5- Canker Diseases- Hardwoods  What trees are susceptible to Neonectria canker ? to N. cinnabarina ? o Neonectria can impact many tree species- birch, beech (beech bark disease), apple, maple o N. Cinnabarina is primarily an issue on “improved” (thornless, seedless) black honey locust  Why is it impossible to eradicate the disease even in a relatively small area? o Once it is in a tree it cannot be eradicated. Preventing damage that can lead to infection is the only real way to prevent it, as fungicides are impractical in full tree applications, this canker is perennial once it is in a tree, and will continue to spread and girdle the tree. Sexual states can often survive on decaying tissue for years.  Where and when was Chestnut blight first discovered in America? o 1904, in the Bronx zoo  Why is it that this disease has been impossible to control? o Moves so quickly- spread from NY down the eastern seaboard in 3-4 years, survived on decaying tissue  What is the future outlook for chestnut in America? o There is hope of a resistant hybrid of the Chinese chestnut with the American chestnut with natural resistance o Genetically modified trees with a wheat gene that produces oxalic acid, a compound that inhibits the fungi’s growth o There is a hypovirus discovered in Europe that infects the fungus itsself and appears to slow it  How do you account for the virulence of this pathogen in America, considering that it causes relatively little damage in the Orient where it is endemic? o Lack of developed resistance- it lives as a saprophyte in china, on branches, does not kill the tree. NA trees had no evolutionary resistance.  Discuss the most promising possibilities for preventing ecological disasters like this from reoccurring in the U.S. o The implementation of the plant quarantine act, wide spread education efforts

List of pathogens/damaging agents/terms to know  SO2  Fluorine  Ozone  Winter sunscald  Frost Cracks  Winter injury  Salt damage  Herbicide damage  Oil base insecticide damage  Iron deficiency  Powdery mildew (Erysiphaceae)  Tar Spots (Rhytisma)  Taphrina  Anthracnose  Apple scab (venturia inaequalis)  Septoria  Marssonina  Black spot of elm  Bur oak blight  Aspen twig blight  Bronze leaf disease  Nectria cinnabarina  Neonectria ditissima  Neonectria faginata (Beech bark disease)  Hypoxylon canker (entoleuca mammata)  Chestnut blight (cryphonectria parasitica)  Eutypella Canker  Urnula Canker (also known as Strumella)  Butternut canker (Ophiognomonia clavigigentia-juglandacearum)  Black knot of cherry (Apiosporina)  Golden canker (Aurantioporthe)  Diamond Willow Fungi terminology  Myxomycota (slime molds)  Ascomycota  Perithicium  Perithecia  Pycnidia  Cirri  Stroma  Asci  Ascospores  Ascocarp  Ascus  Apothecium  Cleistothecia  Deuteromycota  Conidia  Conidium  Conidiophore  Hyphae  Mycelium  Sporodochia  Basidiomycota  Basidiospores  Basidia