Hi! are your fruit trees ornamental or standard fruit-bearing trees? Are they mature or young trees? If they are the standard fruit bearing, my dwarf tree peaches and cheeries coincidentally haven't bloomed since the honeybees and other pollinators disappeared from my neighborhood. Trimming the tree back was of help a few years ago and we had flowers and some fruit. But the critters got them all at once. Then someone told me that they bloom and fruit on the previous year's growth,to prune it lightly every year. So it's confusing to me. I have had aphids, but not now that they haven't flowered. There are peach tree borer insects, and fungus, that could prevent flowering, too. If aphids are creating a problem, you'll see ants on the tree trunk or branches who eat the sticky stuff aphids leave behind. A harsh winter or late heavy freeze or icy weather will also cause them not to bloom. In northeast pa., we have plenty of those. My ornamental cherries and crabapples do bloom with no problem. So i'm stumped too. mary
