I acquired a few trees recently, they went in in April - quite late really but here in west Wales there has been quite a bit of rain in the spring - and in general they've done quite well but while looking at them a few weeks ago I noticed one wild cherry was suffering from a heavy aphid attack - perhaps myzus cerasi, certainly black aphids. I just wiped over the leaves but didn't have time to check the rest until a few days later. What I then found was that some of the cherries that were in treeguards, three out of fifteen or so, were badly infested, the others were clean and the few that did not have treeguards were also clean. I did suspect that the conditions within the treeguard were helping the aphids and so I removed them from the three affected ones. As it happened we then had quite a lot of rain for a couple of days and when I next looked the ones from which I had removed the treeguards looked quite clean and two certainly seemed to be recovering although one still looks rather bad - it's just the leading shoot that looks bad and so it may recover from lower down the stem.
Because these did go in quite late the plants were almost in leaf, and these cherries were also quite bulky - which is why a few didn't get guards, they had so much growth - and so there was quite a lot of congestion within the treeguard.
Two questions: is this unusual ? And should I have removed the lower shoots from the plants to keep the congestion within the treeguard down ? I wasn't told to nor have I seen any such suggestions (although I've not looked too hard). They are the spiral treeguards and in other cases they seem fine; most of the plants were about 75% or more of the height of the guard, the cherries being the largest and almost all were taller than the guards with a lot of shoots down the stem.
graham