can anyone tell me what is wrong with the leaves of a rampant "fan" plum tree?Covered in sticky white flecks that don't move! the tree is too big to spray all over but I don't think it is whitefly.
The white flecks are probably the corpses of dead aphids which have been eaten by ladybirds and other predators. The dead aphids are white and often fall and stick to the honeydew which is being exuded by the live aphids which your tree almost certainly has on the underside of the leaves, particularly near the branch tips.
Give the whole tree a good wash using the spray attachment on a hosepipe, using as much spray pressure as you can. That will knock-off a lot of the live aphids and wash the honeydew from the leaves.
Thanks Bob I will try the spray technique, the leaves all look healthy, the stickiness is on the top of the leaves and I can't see any sign of ceepy crawlies underneath, the plums themselves look ok so far.
It could be that all the aphids have now been eaten by birds or other predators and all you now see is the honeydew they produced and the dead aphids. Washing it down should get rid of that. Careful not to knock all the plums off when spraying - if the aphids have already gone you can use a lower pressure.
Are there any tall trees overhanging the pear? The honeydew could have come from aphids on that - Lime trees are well known for it, for example.