May 15, 2010
May 15 - Pseudoperonospora humuli
The weekend is here - and perhaps that means a nice cold beer or two. One of the main ingredients in beer, of course, is hops, which give brews their characteristic bitter flavor. Hops are dried flowers of the Humulus lupulus plant. Pseudoperonospora humuli is a parasite that could get in the way of your thirst-quenching IPA or ESB, however. This fungus, known as downy mildew infects hop plants and destroys their leaves and those wonderful flowers. A recent molecular phylogenetic study has suggested that P. humuli is not actually genetically distinct from Pseudoperonospora cubensis, another mildew fungus that was described from cucurbits (cucumbers, melons, etc.) So, if you're not a beer-drinker, but do like to enjoy a nice gherkin or melon ball as part your Saturday evening activities, well then, you can be annoyed at the very same parasite.
Image come from this site.