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Plant Diseases/Oak tree disease


Strange structure on the oak tree
Strange structure on t  

Twigs growing out
Twigs growing out  
Good afternoon. The oak tree in our garden (South facing, South of Sheffield , South Yorkshire, UK)
Has no acorns this year. I have attached pictures if what it does have. Long , curved twigs extending
out from the ends of the branches and lots of round insect galls ( oak apples).
Could you identify what is wrong and would it have to be cut down? Or could we cute it , somehow?
Many thanks.
Sally Ward

These do appear to be a type of insect gall. Like many other insect galls on trees, they usually have minimal impact on the overall health of the tree (assuming it has no other underlying issues that can be stressful).  Since many of these insects may overwinter/oversummer in affected twigs, I would suggest raking up any fallen leaves and twigs and burying them or otherwise disposing of them off site.

Other leaves in your image look faded.  This may indicate a nutrient imbalance.  A soil test can reveal what if any nutrients may be out of balance.  A soil test can be performed by your local nursery or garden center.  You did not mention the size or age of the tree.  Be sure to not injure the truck as to damage the bark.  A wound can be a great opportunity for insects and disease organisms to enter and set up housekeeping.  Good fertilization and waterings can promote a vigorous plant.  No acorns can be an environmental rather than a pest issue.  There are a few insecticides out there that can be useful for foliar/twig feeding insects if desired, however there are a lot of insect predators that occur naturally that keep the pest populations under control- making the use of insecticides not necessary or too expensive.


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Dr Stephen Vann


Plant Diseases and Disorders of Lawn Grasses, Trees, Vegetables,and Ornamentals


Plant Diseases Identification and Management

B.S. Botany --- Miss. State Univ. M.S. Plant Pathology --- Miss. State Univ. Ph.D. Plant Pathology --- Texas A & M Univ.

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