On several of my roses when new growth reaches about two inches the very tip dies and turns brown. I have searched for evidence of a pest but don't find anything. I am thinking it is a virus of some sort. Anyone else experience this and any solutions out there?

This sounds like an insect problem but if you are sure it is not, then it may be one of two other things. This has happened to me on several occasions but the new growth was usually greater than two inches in length when the new growth faded. Many years ago I had one or two years of wide spread occurence and my research concluded that I was under feeding my roses. The problem then disappeared, except as I will relate below, once I started a vigorous feeding campaign, including trace elements. The proper feeding campaign for me due to local climate conditions starts in April and is consistent until Labor Day. The other cause may be that the cane is experiencing 'dieback'. I will see this one or twice a year now. I find that the cane, when cut below the dead new growth, has brown in it and is not a healthly looking greenish white. I just prune that cane back to healthly looking tissue, no matter how far down, or remove the cane if it goes down too far. I have never seen 'dieback' described as a disease but as a pruning mistake that initiated a negative and detrimental reaction in the cane. The exact cause in unknown. But once pruned to healthy tissue the cane usually revitalizes.