Pest control and grooming for ferals????

I have an 8 year old very long haired feral named Olive. She was someones pet a long time ago, but was feral when she came to us. we tried to assimilate into our home but she is too skiddish with our indoor cat, and peed everywhere but the box. She has a feral cat house with a heating pad. It is impossible to get frontline or other flea tick products on her. Now ive noticed a large matte of fur above her tail. Suggestions??

Re pest control, you can surely try with DE-earth, just be sure its of human grade quality / food grade. Diatomeus earth

Although healthy semiferales usually do have some immunity against parasites.  Or vice versa, having a good immunity against them, makes it possible for them to be succesful semiferales...

But with mattes on a longhair, its more difficult.

I give mine Capstar; just smash it up in some wet food; it's tiny.  I also spray Vets Best Flea and tick Home Spray on their bedding along with Herbal Flea Powder (all natural).  Just be sure the spray is dried before they sleep there cause it can irritate their eyes if it's still wet.  I use the Datomaeous Earth Food grade (white fine powder) also but I have a hard time using it without getting puffs of powder everywhere, which is what they say is dangerous about it cause it's so fine and can lodge in the lungs.  I'm new to all of this myself, so maybe I am just using it wrong.

I use Program Flea control that you can put in their food.  It is liquid and pretty palatable.  It is given once a month.  I order it from www.bestflea.com