Plant Diseases/Chantacleer pear tree insect infestation?
I have two young Chantacleer pear trees, about 12 feet tall. I just noticed that they have areas throughout the tree where a clump of leaves appears to be dying. When I opened one of the curled leaves, a light-colored spider fell out. I broke off a portion from the other tree and another spider fell out! The spider is a light greenish-yellow color. I don't really see visible webs that would indicate spider mites, which I know are much smaller. Could the larger spiders be eating another pest that I can't see, or is it possible that they are the issue?
From your photos, the symptoms strongly resemble a bacterial disease called Fire Blight. The spiders are doing no harm and are probably there incidentally for shelter or for eating insects.
Fire blight can be serious under certain conditions. It can eventually kill the tree. Wet/cool and cloudy springtime weather are conductive for this disease. Selectively removing affected portions by correct pruning techniques can be useful if practical and feasible. There is a lot of information on the internet about this disease- much more thorough than I can write here. Many ornamental and fruit bearing pears and apple varieties can be very susceptible. The bacteria often enters the twigs through the flowers and is carried by pollinating insects such as bees. High value trees can be sprayed with an antibiotic, but timing and coverage is important for the chemical to work.
As I mentioned, check out the internet for more detailed information. Many universities have publications on line that can give you a better insight into this infectious disease.