The Attack of Downy Mildew!

Well it has happened again, for the second year in a row our gorgeous beds of Basil have been overcome by an infestation of the dreaded Downy Mildew!  It literally happened overnight.  We came down to the garden Thursday morning and discovered the fungus on 2 of our Basil beds.  By Friday, we found it on our 3rd bed of Basil as well as some of the basil we planted as companions around our cucumber and tomato beds.

Downy mildew is a "new" problem in the US, with the first reported cases in 2007.  Since then, the pathogen has spread quite rapidly, especially as more people are recognizing the signs.  One of the main signs of an infestation is a yellowing of the leaves, which resembles a nutritional deficiency.  The other main sign of downy mildew is a sporulation of the fungus on the lower leaf surface, which is the dark fuzzy stuff we had observed.  The pathogen, Peronospora belbahrii, can be transmitted through the air, or also through unknowingly contaminated seeds, which is likely responsible for the rapid spread of the pathogen throughout the world.  It appears that sweet basil may be more susceptible to downy mildew than other more ornamental varieties.

Unfortunately, we had to pull up all our basil and put it in bags to be placed in the trash dumpster (composting it would allow the spores to travel around - which we do not want).  We had a wonderful crew of OVE volunteers Friday afternoon helping us take care of all the basil - though it was a very sad thing to have to do, it was very necessary.

We're hoping that our remaining basil around our back Pepper bed is still okay - if not -- our basil is done for the season at the Farm Stands.  We will however have some delicious Delicata Squash, okra, watermelon and cantaloupe in addition to all our usual veggies!

Comments

Popular Posts