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Biology/oak leaf fruit

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Expert: - 4/18/2009


Question

oakleaf_fruit
Can you tell me what this strange fruit is? it is growing off our oak leaves.

last year i noticed that it had round, young green fruit on it. Stranger still the
fruit was growing off of the leaves. Later the fruit would grow brown and
shrivel. when the fruit is still young, it grows quickly to about 1.25" diameter
and then begins to go from yellowish green to dark green to brown.

I cut a young green one open and it has a spongy inside. the fruit is very light
to hold. No nut in the middle. No seed. very grainy.

It is happening again this year. and this time  It is between 4-10 years old. It
was here when we moved here 3 1/2 years ago. It doubled in size since we
moved here. when we were first here it was about 10 feet tall and now it is
over 20 feet tall.

Answer
What you are describing are called oak tree galls.  They are not fruit, but rather an abnormal growth caused after a tiny wasp injects her eggs into the leaf.  The galls do not hurt the tree.  For a lot more information about galls and the insects that cause them, see the following link:

http://insects.tamu.edu/extension/bulletins/L-1299.html

Chris  

Chris Bemis

Expertise

I will answer questions relating to the identification of bacterial and fungal isolates using phenotypic (macroscopic/microscopic appearance, biochemical bench tests, fatty-acid analysis) as well as genotypic (RiboPrinting) methods. I can also answer questions relating to environmental microbiology, especially those specifically relating to the pharmaceutical industry. I am less familiar with clinical microbiology.

Experience

I have worked within the biotech industry for 9 years, most of that time spent in a Quality Control Microbiology laboratory setting. Within the laboratory, I routinely performed bioburden testing; sterility testing; gel-clot and kinetic LAL testing; biological indicator testing; stability testing; microbial limits testing; media performance/growth promotion testing; microbial identifications testing using API, Vitek, MIDI (GC-MIS) and RiboPrinter identifications systems; total/fecal coliform testing; environmental monitoring; media preparation; stock culture maintenance; qualification of identification test kits and QuantiCult Plus organisms. I executed the QC validation of the DuPont Qualicon RiboPrinter Microbial Characterization System. I also supported sites internationally with the fungal/microbial identification process, the RiboPrinter assay, stock culture maintenance and the microbial identification process flow.

Organizations
Nationally Registered Microbiologist, American Society of Microbiology (2005)

Publications
Applied and Environmental Microbiology

Education/Credentials
B.S. in Microbiology (2000)

Awards and Honors
Received my company's 'Best Practice Award' for the Validation of the RiboPrinter Microbial Characterization System, 2004

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