how to treat influx of Conifer plant pests
Jefferson County Colorado
I apologize for the delay in answering your questions. Based on the pictures you sent I believe your Aspen tree has a form of rust. At this point it is not necessary to treat the rust. It is best to carefully clean up the leaves and discard them, not compost. A fact sheet on Aspen and Poplar Leaf Spots can be accessed here: https://extension.colostate.edu/docs/pubs/garden/02920.pdf
The Hawthorn tree appears to have Juniper-Hawthorn rust, a common fungal infection that requires both a Hawthorn tree and a Juniper shrub/tree to complete its life cycle. It is primarily an aesthetic problem that can be controlled with good fall leaf cleanup. If serious infection occurs over several years, treatment options are available, as decribed in the CSU publication https://planttalk.colostate.edu/topics/insects-diseases/1450-juniper-hawthorn-rust/.
The beetles on your fruit appear to be spotted cucumber beetles. They have been very numerous this year and many gardeners have complained about them on all of the cucurbits, but also on roses and many other flowers and vegetables. At this point it isn’t necessary to treat for them, because they will die with frost. However you need to read up on the various ways to thwart them in the spring. Traps, hand picking, row covers and other methods are discussed in this article. See https://extension.umd.edu/hgic/topics/cucumber-beetles-spotted-or-striped-vegetables
If you have further questions or concerns you can bring samples to the Jeffco clinic for evaluation. ($7 charge per sample) The Clinic is located at the Jeffco Fairgrounds, email@example.com, 303-271-6620.
This growing season has been difficult for many of our plants due to the cool wet spring.