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Raspberry Crumble

Raspberry harvest is in full swing in Ontario. The summer crop of raspberries usually comes and goes in the space of a few short weeks. During that time, we hope for good weather. Growers like to harvest raspberries early in the morning, before the day gets warm, but, it is also important to wait until the dew evaporates and fruit is dry. Rainy weather during harvest can create problems with fruit rots. It is important to keep on top of the picking in these conditions. Keep all ripe fruit picked on a regular basis.

Raspberries are so fragile! They must be handled gently and cooled quickly after harvest. Another tip for maintaining a high quality product is to harvest into small ½ pint containers so that fruit is not crushed.

One problem that shows up at harvest is crumbly berries. This is how we describe fruit that falls apart in your hand when picked. The individual drupelets that form the fruit are not cohesive and do not stick well together. There are several things that could cause this condition.

Sometimes, a variety tends to be crumbly, just because of its genetics. These varieties usually have a weak neck or collar where the fruit detaches from the plant.
Poor pollination and very low humidity during pollination can cause crumbly fruit, especially in greenhouses or high tunnels. Symptoms generally do not recur on the same plants the following year.

Sometimes crop nutrition is a factor in crumbly berries. To diagnose this problem, do a leaf analysis for micronutrients and test the soil pH.

Plant virus diseases such as raspberry mosaic, and tomato ringspot virus are the most common causes of crumbly fruit. Symptoms develop in a few small areas in the field, and re-occur in the same place every year. Affected areas gradually expand and the planting becomes unproductive with time. Virus diseases can be diagnosed at the pest diagnostic clinic at the University of Guelph. The lab there has recently expanded the number and types of tests that can be done to diagnose virus diseases.
Crumbly fruit has several causes. However, affected fruit is edible. Although it is difficult to harvest, it makes a great berry crumble.