Leaf stoma diseases

Asked February 22, 2013, 10:51 AM EST

When the stoma is open on the underside of the leaf what disease can enter the stoma and infect the plant. If there is an RPD could you send that also. Thank you very much

Lee County Illinois

1 Response

Well, theoretically, any fungal or bacterial organism can enter the leaf through the stomates. Not all of them have to, but they can.

For example, Cornell mentions this route of infection specifically for strawberry leaf spot: http://www.fruit.cornell.edu/tfabp/strawleafspot.pdf . Ohio state discusses how downy mildew enters grape leaves through the stomates: http://www.oardc.ohio-state.edu/fruitpathology/organic/Grape/downymildew.html . And bacterial leaf blight of soybean can also infect the leaf through the stomates: http://www.soybeans.umn.edu/resources/news/news_8-10-01.htm .

Now, to apparently play Devil's Advocate, this research study from 2006 states that bacteria do not easily enter a leaf through the stomates: http://www.public.iastate.edu/~ajbog/PlP692/Melotto2006Cell.pdf . The ability of the stomates to close prevents infection.

I hope this sufficiently answers your question. If you need more information, please send your request directly to me, instead of through eXtension.