Pear tree help me please

Can anyone please tell me what is happening to my pear tree please

Is the last one a rust? There's one affects apples, alternate host (rusts have two) of juniper. Is there something on your leylandii, which isn't far from juniper?
Webbing seems to be hosting spiders, but what's eating the leaves hard to tell.

Pear juniper rust I wouldn't even worry about it. It deforms the leaves a bit and occasionally the fruit but its not a big deal. The leaves could be tent caterpillar I wouldn't be concerned if only a few leaves are eaten. If you didn't inoculate it with some mycorrhizal fungi go water some in and mulch the tree with some woody material and it will probably do a lot better.

make jadam sulphur, and spray that on anything that has a disease

Looks like spider mites. Chrysanthemum extract will deter them. Make sure it has a clearance from other trees/shrubs like juniper where the mites nest.

I think the fact that each damaged leaf has a web or string to it suggests spider mites. If they get out of control, they will kill your tree. A couple of years ago I had spider mites kill two pears and three plums before I figured out what was wrong. These were 1" trees about 6' tall. My well established 10' pear tree suffered damage but was strong enough to survive and recovered in the spring after the winter killed off the mites. I noticed some signs of infestation on different trees this past spring and after the blossoms were done, I used some soap and essential oils to help my trees fight the teeny tiny attackers.

Jenny Wright wrote:I think the fact that each damaged leaf has a web or string to it suggests spider mites. If they get out of control, they will kill your tree. A couple of years ago I had spider mites kill two pears and three plums before I figured out what was wrong. These were 1" trees about 6' tall. My well established 10' pear tree suffered damage but was strong enough to survive and recovered in the spring after the winter killed off the mites. I noticed some signs of infestation on different trees this past spring and after the blossoms were done, I used some soap and essential oils to help my trees fight the teeny tiny attackers.

I think your both right spider mites never had them kill an entire tree before, though we have crazy amounts of lacewings wasps etc from the various umbellifer flowers. Was it a particularly hot summer or stressful year for the trees?

It looks to me like you have 2 problems, spider mites? but also watering too much? your tree looks weakened like maybe you have a root rot problem also. I would check the depth of moisture in your soil at that tree, you could also check the roots at the same time. We had the same type of problem on a couple of stone fruits but got to it too late. Had we diagnosed it sooner we could have saved them. I would spray with "neem" oil and add a "neem" oil dilution to the soil when you water next you can also make a "rosemary" tea and add it to the water, insects do not like rosemary or neem oil. Watering with these solutions will allow the tree to uptake them all the way to the leaves and help repel sucking insects.