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Oak Tree Disease

       With the Bur Oak (Quercus macrocarpa) as the Iowa State Tree and our Local Hockey team being named the Oak Leafs, Iowa is synonymous with Oak trees. Arborists in Des Moines, Iowa categorize Oak Trees into 2 groups Red oak and White Oak. Olson Tree Care identifies Oaks with pointed leaves as Red Oaks and Oaks with rounded leaf margins are White Oaks.

       In the White Oak Group is white, bur, chinkapin, dwarf chinkapin, swamp white, and post Oaks. In the Red Oak Group is red, pin, black, northern pin, shingle, and blackjack.

       The 2 most common Oak Trees that Olson Tree Care works with on a regular basis are Bur Oak and Pin Oaks. These 2 Oak trees can also be broke down into 2 Oak Tree Disease categories, Oak Wilt and Bur Oak Blight (BOB)

       Oak Wilt can effect many oak trees, it moves more quickly in the Red Oak group. Due to populations in the Urban Environment the Arboriculturist at Olson Tree Care in West Des Moines, Iowa deals the Oak Tree Disease of  Oak Wilt effecting Pin Oaks more frequently. Bur Oak Blight on the other hand effects Bur Oaks and diagnosis is relatively easy.

Bur Oak Blight

      Bur Oak Blight is a recent fungal pathogen (Tubakia iowensis) to be discovered in Iowa. This fungal pathogen is spread by contact to the new stem growth during spring and is not evidenced until later in the growing season.

      Bur Oaks and White Oaks are often confused so proper identification by a Tree Tree in Des Moines, Iowa is important. Olson Tree Care has a worldwide leader in Arboriculture on staff, ISA Certified Chris Olson (We-12363A, TRAQ, Licensed and Certified Pesticide Applicator).

       Once a proper ID has been rendered, diagnosis of an Oak Tree Disease is required. Tree Care professionals are taught that 2 symptoms must be present for a diagnosis. Some common symptoms are leaf necrosis in a wedge shape along leaf vein, random dieback (spotty small sections), Dieback starts lower and progresses higher, (Most contact fungal pathogens work this way), intensity increases yearly. This does not move quick and sudden like oak wilt but will result in death of the tree.

       Fungicide injections at strategic times have proven to be effective in controlling the spread of Bur Oak Blight (BOB). The Arboriculturist at Olson Tree Care has observed complications arising from stressed oak trees which is preferred by the Two Lined Chestnut Borer. Piggy bag applications of insecticide are standard care.


Bur Oak Blight

Oak tree Disease

Oak Wilt

Oak Wilt

       Oak Wilt is a common Vascular Pathogen (Bretiella fagacearum) that spreads through vector or root grafting. The vector comes in contact with the fungal mats and spreads spores to other oak trees. The pathogen causes the Tree to respond with a thick substance in the vessels responsible for uptake. This less permeable substance restricts uptake causing wilting in summer. Most times it is followed closely by tree death. 

       Testing can be done through the ISU Research Extension although Olson Tree Care's experience is that it can be complicated as they are understaffed at times. 2 symptoms identified are equally as powerful for diagnosis so Consulting a qualified Tree Service in Des Moines would be advisable.

       Symptoms of Oak Wilt.

- Random dieback (biotic injury is random, Abiotic pin oak chlorosis is more uniform in nature)

- Leaf Necrosis in the form of leaf scorch or discolored leaf veins. The variance is that leaf scorch from heat stress or drought shows up evenly on the tree.

- Discoloration to the sapwood under the cambium.

       If your tree has Oak Wilt treating all of the trees on the property with fungicide followed by a piggyback insecticide injection is standard care for a Licensed and Insured Tree Service in Des Moines that has an Arboriculturist on Staff. Feel free to contact Olson Tree Care for a paid Consultation

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