Heat & Light Stress Part 2

Heat & Light Stress Part 2.  I’m Greg Martin with today’s Fruit Grower Report.

Tree fruit can suffer from heat stress just like the human body. When outside air temperatures and humidities reach higher levels, apples, cherries, pears and more can suffer damage. Larry Schrader with WSU says on a 90 degree day the surface temperature can reach 120 degrees.

SCHRADER: If you bump that air temperature up another 10 degrees we’re almost cooking that apple. So it’s not hard to realize that the apples are probably really suffering at times under these conditions. And the result is that several different fruit skin disorders can be induced under these stress environments.

And before you ask, yes, fruit can suffer from sunburn just like you and I.

SCHRADER: There are others that appear as well. Some of them appear before harvest and others appear later. 

Besides sunburn Schrader says damaged lenticils can appear brown or black on the surface of the fruit. Another problem is called water core where the center browns and breaks down.

SCHRADER: And likewise bitter pit can be exacerbated by a heat wave that can come in shortly before maturity. 

There are other problems that do not show up until after the fruit is in cold storage including Fuji staining and sunburn scald. On Monday Schrader will discuss some of the ways you can combat sunburn in your orchard. That’s today’s Fruit Grower Report. I’m Greg Martin on the Ag Information Network.