Thursday, May 22, 2008

Pythium root rots of bean and watermelon seedlings

Today was a day of root rots! Two samples of pythium root rot but both came in with complaints of foliage problems on field transplants (browning and death of bean leaves & wilting of watermelon). Luckily, the submitters had included the full root system and soil so we were able to quickly make an accurate diagnosis. Pythium agar was used to confirm the presence of Pythium spp. Note the characteristic stem lesions.
Pythium root rot on snap bean transplants:

And Pythium root rot on watermelon transplants:

Wednesday, May 21, 2008

What's your plant's problem?

Did you know that most U.S. states have a clinic that will diagnose your sick plant for a small fee? The American Phytopathological Society maintains a list of all university clinics. Click here to find one in your state!

Wednesday, May 14, 2008

Fennel-Unknown problem

Another delicious smelling sample- fennel (Foeniculum vulgare). This sample presented with browning on the edges of stems at the bulb. The very oldest leaves are yellowing and dying. The main cause is likely that the plant is pot bound (roots are curling around at the bottom). There was no internal decay in the bulb and the majority of the foliage was fine. The bulb is incubating to double check.Above photo is a little bleached out, note that the Jiffy pot has been pulled away for the photo.

Cut edges are starting to brown as I took the above photo ~10 mins after cutting.