Volck oil spray discontinued?
As a member of extension I can't make a brand recommendation. The Volck oil is pretty basic- Active Ingredients:97% Petroleum Oil* *(Pet. Oil-Min. U.R. 91% - Class Lt. - Med.)
You will have to examine the labels of the many competitive products available to find a replacement that is labeled correctly for your desired application. I am attaching links to CSU's excellent information on horticultural oils- http://www.ext.colostate.edu/pubs/insect/05569.html
If you have other questions that this information doesn't answer please contact me directly.