“What is a witch’s favorite subject in school?”/“Spelling.”

A witch riddle included in many Halloween joke collections is:
 
Q: What is a witch’s favorite subject in school?
A: Spelling.
 
The joke appears to have been included in the book Witches, Pumpkins, and Grinning Ghosts: The Story of the Halloween Symbols (1972) by Edna Barth. “What subject do witches like? Spelling” was printed in a 1990 newspaper.
 
 
Google Books
Witches, Pumpkins, and Grinning Ghosts:
The Story of the Halloween Symbols
By Edna Barth
Illustrated by Ursula Arndt
New York, NY: Clarion Books
1972
Pg. ?:
What is a witch’s favorite subject in school?
Spelling.
 
Google Books
Biggest Riddle Book in the World
By Joseph Rosenbloom
Illustrated by Joyce Behr
New York, NY: Sterling Publishing Company, Inc.
1976
Pg. 92:
What is the most important subject a witch learns in witch school?
Spelling.
 
14 November 1990, Lansing (MI) State Journal, pg. 8E, col. 4:
Rebecca Puente
Grade 5
Willow
What subject do witches like?
Spelling.
     
Google Groups: alt.support.arthritis
Halloween chuckles
AM
10/18/98
(...)
Q: What was the witches favorite subject in school?
A: Spelling.
 
28 October 1999, Los Angeles (CA) Times, “The Kids’ Reading Room; Reading by 9; Pint-Sized Punch Lines,” pg. 7:
What is a witch’s favorite subject? Spelling. (Mia, 9, Fair Avenue Elementary School, North Hollywood)
 
Google Groups: alt.halloween.boo
Halloween Jokes
stirling
11/8/99
(...)
Q. What is a witch’s favorite subject in school?
A. Spelling!
 
Google Books
Jokes, Riddles and Wisdom:
The Best Collection Ever
By Roger Kuder
San Jose, CA: ToExcel Press
2000
Pg. 55:
What was the witch’s favorite subject in school?
Spelling.
   
Google Books
Puns Spooken Here:
Word Play for Halloween
By Richard Ledere
Illustrations by Jim McLean
Layton, UT: Wyrick & Company
2006
Pg. 47:
What was the witch’s favorite subject in school?
Spelling,
 
Twitter
Carol Howard Merritt
‏@CarolHoward
What was the witch’s favorite subject in school? Spelling. (Jokes you learn when you live with a 2nd grader).
12:59 PM - 22 Nov 2008
 
Twitter
ratulnarain
‏@ratulnarain
what is a witch’s favorite subject in school?...spelling
11:40 AM - 23 Dec 2008
 
Google Books
The Super, Epic, Mega Joke Book for Kids
By Whee Winn
Grand Rapids, MI: Zonderkidz
2016
Pg. ?:
What is a witch’s favorite subject in school?
Spelling.