WEST LAFAYETTE, Ind. — With the help of sponsorship by the Indiana Horticulture Conference and Expo, Purdue Extension has been able to host a series of fruit management webinars. The first focused on the apple crop.
Peter Hirst, a professor of horticulture at Purdue University, said what happens one year with an apple tree can affect how that same tree produces fruit the next year.
Due to a late freeze on May 9, after two other freezes in mid-April, more than 80% of the apple crop in the Indiana was killed off and much of the fruit that did develop was damaged in 2020, Hirst said.
“What happened last year may not happen this year,” he noted.
Despite not having a crystal ball and being able to 100% predict the apple outlook for this year, Hirst believes that if growers get a few more weeks of cool temperatures instead of warmer ones, preferably lower than 50 to 60 degrees, the development of the fruit crop will slow down.
The process of fruit development for this year’s apple crop actually started last year and due to how hard the fruit was hit the previous year, the apple tree will produce a lot of flowers for the following year, Hirst explained.
In turn, management intervention is necessary every other year because there isn’t much to do during the off-year besides manage the trees.
“This year there will be tons of flowers,” Hirst said.
If every bud flowers, there is the potential for a huge crop, but the size and quality of the fruit could be negatively affected because of uneven pollination and the tree using up a lot of energy to help all that fruit grow, he said.
Too many flowers on a tree can be a problem, Hirst said, so growers need to practice crop thinning, either manually, which can be quite labor intensive, or by chemical thinning.
