Sir William Dugdale (Life, Diary, and Correspondence of Sir W. Dugdale, edited by W. Hamper, 1827, p. 104) tells us that formerly, on Halloween, the master of the family used to carry a bunch of straw, fired, about his corn, saying:
"Fire and red low
Light on my teen now."
This fire-straw, says a correspondent of N. & Q. (3rd S. vol. i. p. 316), was meant to ward off witchcraft, and so preserve the corn from being spoiled. In Scotland, on Halloween, the red end of a fiery stick is waved about in mystic figures in the air to accomplish for the person the same spell. Red appears to be a colour peculiarly obnoxious to witches. One Halloween rhyme enjoins the employment of:
"Rowan tree and red thread,
To gar the witches dance their dead ;"
i.e., dance till they fall down and expire. The berries of the rowan-tree (mountain-ash) are of a brilliant red. The point of the fiery stick waved rapidly takes the appearance of a "red thread."
Source: British Popular Customs Present and Past, Illustrating the Social and Domestic Manners of the People, Arranged according to the Calendar of the Year, by the Rev. T. F. Thiselton-Dyer, M.A. Pembroke College, Oxon. London, George Bell & Sons, 1900