Bugs give berries multicolors

Q. Why do my blackberries have cream-colored spots all over them?

Oran from Alliance

A. The berries brought into the clinic were from dark purple to red and white or cream- colored. There was uneven ripening, but several of the drupelets (the individual compartments that form the compound fruit/berry) were this white or cream color.

This is becoming a common problem for blackberry and raspberry growers. And, for the most part, this is a fairly new phenomenon. Many growers tend to see these white drupelets during the first set of ripe berries.

Purdue University states that there may be several other explanations of causal factors for this condition, including stinkbug feeding damage, red berry mite feeding damage, sunscald and UV radiation. Insect feeding may lead to several different colors of drupelets on one berry.

Most of what we are seeing looks to be UV damage to the drupelets.

More specifically, the University of Arkansas reports the UV damage is more significant when temperatures increase quickly, followed by a drop in humidity and lots of wind.

Basically, most white drupelets are not diseases, but disorders. There is also a dry cell syndrome, of which we do not know a cause. Be sure to inspect plants for other signs of disease before determining the cause of the problem.

What can you do?

Plant breeders say breeding is the answer, that this is an inherited trait. This will take some time to figure out. For now, pay attention to proper growing techniques, and especially pruning practices to reduce disease pressure and to ensure healthy plants. Need help pruning? Read our factsheet at: http://go.osu.edu/pruneblackberry

Eric Barrett is the Ohio State University Extension Educator for Agriculture and Natural Resources in Mahoning County. Call the office hotline at 330-533-5538 Mondays and Thursdays from 9 a.m. to noon to submit your questions.