A Purdue University horticulturist says Indiana's recent sub-freezing temperatures might have damaged grape vines lured into budding early by March's unseasonable warmth.
Purdue horticulture professor Bruce Bordelon said widespread damage to Indiana's grape crop occurred in 2007 and 2012 when April cold followed March warmth. He said the same damage is "very possible" after last weekend's sub-freezing temperatures and more cold forecast this week.
Bordelon said grape growers can avoid some crop losses by practicing a pruning technique that calls for them to avoid pruning grape canes until after the last probable spring freeze has passed.
That leaves secondary shoots as a backup if the primary shoots are cold-damaged.
Bordelon said "secondary shoots are not as fruitful as primaries" but they can still result in near-normal yields for growers.
Indiana typically has more than 650 acres of wine grapes in production annually, Purdue said, and the state has more than 70 wineries that produce more than 1 million gallons of wine each year.