To: "North American Fruit Explorers" <nafex@lists.ibiblio.org>
Subject: Re: [NAFEX] peach leaf curl/resistance
Date: Mon, 4 Jun 2007 17:01:38 -0500
The new growth that develops after petal fall is not affected by peach leaf
curl and quickly hides the defoliation caused by leaf curl. However, severe
infections that cause more than 10% defoliation can result in reduced fruit
size. A few scattered infections cause no significant damage to the trees,
but they can provide overwintering inoculum for the following year. Adding
additional fertilizer heavy in nitrogen and additional water in dry periods
can help trees combat curl and rejuvenate from an outbreak, especially if
copper was applied this spring, even though it may have been a late
application. We used a new organic fertilizer this season on our apple
trees and I applied it to our peach trees that had curl after our copper
spray and it brought them right back within 2 weeks. We kept the irrigation
on for that 2 week period at 1/4 the normal rate to avoid over watering and
it worked like a charm.
If you had problems with peach leaf curl this season, you can treat the
disease in the fall. The best timing for application is during leaf fall in
the fall. The longer you wait the better. You need good coverage of the buds
exposed when the leaves fall off. This means that the best time to spray is
after the first frost. This is especially true with young trees, which hold
on to their leaves until the really cold
weather comes in late November.