many of my home grown individual raspberries and marionberries ripening enevenly #256640 - Ask Extension


many of my home grown individual raspberries and marionberries ripening enevenly #256640

Asked June 23, 2015, 11:48 PM EDT

I have a few rows of raspberries and marionberries I have grown for years. I am finding an increasing percentage of the individual berries are ripening enevenly, with many of the raspberries remaining hard and not ripening at all. The marions are now in and over half of the berries partially turn black and partially remain red and/or hard. Any links or thoughts you can give me to research possible causes appreciated. Thanks. George Hamilton

Clackamas County Oregon

Expert Response

Your fruits may be affected by redberry mites. These mites are very tiny and are quite different than the more common spider mites. They survive the winter underneath the bud scales. Sprays must be used while the fruit is still green.


In home gardens, choose between lime-sulfur and a superior-type horticultural oil. Apply lime-sulfur to the canes in spring when vegetative buds are about a half-inch long; repeat application in the fall. Or apply a superior-type oil and apply when floricane lateral growth (fruiting growth) are 2 to 6 inches long; a fall application is optional. If you have not used horticultural oils on your blackberry plantings before, it’s wise to test it on a small portion of the planting first, to check for possible damage from the oil. Several more cautions include these: Don’t apply oils within one month of treating with sulfur; And don’t apply oils when temperatures exceed 90 degrees.


Because of our recent mini-heatwaves with clear skies, we need to be certain this is not sunscald. In this case, the affected drupelets (individual fruit cells) on the sunny side of the berries turn white.  They eventually dry and turn brown.


Resources for you:

Redberry mite -

Growing Blackberries in Your Home Garden -

Growing Raspberries in Your Home Garden -

Jean R. Natter Replied June 24, 2015, 3:19 PM EDT

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