Skip to main content

More discussion on powdery mildew!

I guess both Anton and I tend to work on Sundays...  He send me two nice pictures of flag shoots.
and
As you can see leaf surface is covered with white powder (= mycelium and spores of powdery mildew).

He also mentioned that he has used Armicarb and sulfur together and did not see any phytotoxicity.  Thus, if your intention is to fight against established colonies (whether flag shoots or late in the season), it would be a good combination.  If Armicarb or Kaligreen is too expensive for your budget, a straight sulfur application is the alternative.

The other thing about powdery mildew is the effect of cold temperature.  According to a recent study by Cornell, low temperature (8 hr of below 8C or 46F) stops the powdery mildew activities. This is another reasons why we do not see much activity of powdery mildew relatively early in the season.  Hopefully, we have enough cold (but not freezing) nights ahead of us to stop early season powdery mildew.
Labels:

Comments

Post a Comment

Please leave your comment here. In order to avoid spam messages, l moderate comments, thus it may take a few hours for your comment to be posted on the page.

Popular posts from this blog

Downy mildew gallery

At Winchester, we had light rain events during the night of 6/12/09, but it was short events and the relative humidity was low (80% or so), thus it probably did not promote any infections. However, we are experiencing continuing favorable nights for downy mildew sporulation (average T>55F, high RH (80-100%)) for 10 days now. Yesterday, we conducted a formal disease assessment, and observed first incidence of powdery mildew for this season. We had plenty of infection events in last two months, so it was not surprising. At this point, it is a trace level of infection on untreated vines. Downy mildew was the major disease so far. We had up to 40% incidence on untreated vines. Next runner-up was black rot. It varies vine to vine, but some of vine had 10-15% incidence. Phomopsis was omnipresent as I expected from early May rain falls, but severity was low overall. We will examine diseases again in the near future, and I will update as the season goes. Here is downy mildew ga...
Post a Comment
Read more

Season's Greetings!

I hope you and your family have a good holiday season and a Happy (and safe) New Year! Thanks again for your support of our programs. Here are some recent media highlights. 😉 The link will open a new window. AHS AREC promotional video  that highlights some of our activities. The link did not work... It asks you to log in to VT. I will request the IT people to change the setting, but in a meantime, here's the same video. We also appeared in  the Library of Congress project “Winery Workers of Virginia”. One more announcement: I will be moving this blog to a new location ( ext.grapepathology.org ) early next year. I had to make a change due to the email subscription service, which has been terminated.  You do not need to change your bookmark or your email subscription. The URL will be forwarded to a new site and your email subscription has been moved to a new site already. 
Post a Comment
Read more

Up-coming meetings and Sentinel Vineyard Report #2

  I think many readers of this blog subscribe to Tony’s viticulture note, but just in case, here is some information that you may be interested in. The second Sentinel Vineyards Report is out now.  The report is attached at the end of this post.  Make sure to subscribe to Dr. Beth Chang’s Blog here:  https://sites.google.com/vt.edu/vtenology/home Two upcoming meetings: New Grower Workshop 4 November 2021 at Winchester VA Team taught sessions for new grape growers and those considering developing a wine grape vineyard in the Mid-Atlantic.  Registration is required ( and the deadline is this Friday! ). Please click the link below.   https://register.ext.vt.edu/search/publicCourseSearchDetails.do?method=load&courseId=1600122 Virginia Wineries Association Annual Meeting November 15 & 16, 2021 Hybrid event: in-person (Richmond, VA) and remote virtual options The technical session theme on Day 2 is “Wine Stabilization – ...
Post a Comment
Read more