My pick for worst episode of "Petticoat Junction"was one of those episodes WITHOUT Bea Benaderet.The one where Uncle Joe fumigated the hotel.It was just plain BLAAAAH.It was really saccharine.

I have a few to add.
1)The Glenn Tinker Caper: WTF?! We're they thinking when they did a "topical" episode about a country singer smuggling a Vietnamese orphan in his backpack. Abysmal in every since of the word.
2) The Christening: This episode had some humorous moments, but most of it was quite serious. The final scenes of Kathy Jo's baptism and then Steve singing "The Lord's Prayer" were done in a very serious matter with hardly any comedy at all made me wonder if this was "a very special episode" long before that term was coined. Was Petticoat Junction changing from a sitcom to a comedy-drama(or "dramedy") at this point? This is something I would expect from "The Waltons" or "Little House On The Prairie" and NOT "Petticoat Junction
3) Love Rears It's Ugly Head: Again, another "very special" episode, in which the now turned hippie. Billie Jo, wants everyone to get along and love one another. Another serious ending with Steve Singing "The Impossible Dream" Nice to see Billie Jo take center stage in this episode, but still..
4) Goodbye Mr. Chimp: A nice return to the slapstick comedy of the early seasons, but a pointless part 2 to the fantastic "Kathy Jo's First Birthday" Just Not funny at all.
All 4 of these are from the post-Bea Benaderet period.