Hello Terry,

Are these canes that have already borne fruit or are they newer canes? When did the damage appear? Was there any damage on leaves?

This may be cane blight, a fungal disease which can infect wounds in the plant caused by physical damage or insects. Do you have a picture of an infected cane that is not already dead?

Management for different cane diseases is pretty similar- improve airflow in the raspberry patch by pruning and keeping up the maintenance of the plants. Prune out any diseased canes and remove floricanes (second year fruiting canes) after harvest. If the problem persists into next year then fungicides could be used in the early summer.

The ants would be attracted after the wounding, so they are secondary and not a cause.

It's hard to say exactly what is going on at this point, but your response to my above questions should help.