WARNING: THIS IS A SCIENTIFIC ANSWER FROM SOMEONE WHO KNOWS WAY TO MUCH ABOUT LEFT 4 DEAD
Well you see my good man, when Witches are transformed by the Betazene virus, (The virus commonly reffered to as the "infection") the virus reacts with a special genome found within the hosts body. This genome is called "Milus P.P." and is only found in females. The genome is dominant at a young age, and gradually grows into recession as time moves on, which is why all Witches are young females. If the host has the Milus genome, and if the genome is in a dominant stage, the Betazine virus will react with the genome, chemically reacting to form a viral compound known as "Lycosis". The Lycosis viral compound is similar in the structure of diabetes, stopping the Witches natural sugar production, but still retaining the "Mad Cow" effects of the Betazine virus. (Immunity to pain, loss of most major motor skills, extreme violent tendencies, degradation of mental stability.) This causes the Witches to seek out sugar, whether it be taken in as forms of plants such as sugar cane or.......... OK, I cant do this any more. I just bullshitted that entire thing.
Witches don't like sun.
Rain=No sun
Rain was at sugar mill
Witches go to sugar mill.
Simple.
