Typical appearance of leaf yellowing caused by Glomerella leaf spot. |
Glomerella leaf spot and fruit rot from Nelson County VA, 2011 |
Glomerella leaf spot was reported in TN in 1998. It built up in NC in 2004 and became more prominent with wet weather in ’05. The following winter I began to receive reports from growers and consultants who thought they may have seen it in southern VA. It became prominent again in southern VA/NC in 2010 and caused some problems in Nelson County, VA in 2010-11.
Recommendations for control as we approach harvest depend on market plan for the affected variety and the days to harvest. Pristine is the single most effective material that may be applied close to harvest. Other possible options include Flint + Captan and Captan + potasssium phosphite.
Leaves are an important overwintering site and overwintering inoculum can be reduced by shredding leaf litter with a flail mower or applying a foliar spray of urea at leaf drop. This can also aid in suppressing other foliar diseases such as apple scab and Alternaria leaf blotch.
Leaves are an important overwintering site and overwintering inoculum can be reduced by shredding leaf litter with a flail mower or applying a foliar spray of urea at leaf drop. This can also aid in suppressing other foliar diseases such as apple scab and Alternaria leaf blotch.
WEEKEND WETTING: Split extended wetting periods of 14 hr and 10 hr occurred with a total of 0.75 inch of rain at 70° Aug 25-27. We also had several nights of heavy dews last week, bringing the accumulated wetting hour total from rainfall or dew since Apr 18 to 909 hours.