Answer: I'm afraid impatiens don't like hot weather and if you keep the soil too moist, they can develop a disease that collapes the stems. I'd pull the plants out of the garden and replant healthy new plants next spring.
I would prune away the infected plant parts on your pear tree. They may be a result of hot weather and/or drought, or they could be symptoms of a disease called fire blight. If the problem returns again next year it may indeed be fireblight and your tree will need to be sprayed on a regular basis. Let's hope the problem is just weather related and won't return next year!
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