Why Halloween have to use Pumpkin?

(Picture taken from the Poni Divers Brunei)

Recently I saw many people post their Halloween's costume picture in Facebook. They seen like having fun there. Halloween day....most of the people here they only know the night go party have to dress up like ghost, died man, monster, cartoon people etc.
Go party have fun and get drunk and that is all we want! Right!!! Yahoo...... Party all night long!!!Btw who care right what is that Halloween for!!! 
But let me tell you this... Halloween night is the worst nightmare for the man in the party!
Because man always do the wrong thing in the Halloween party, the reason is because when man drunk the time whatever they see also look good one! Pink Piggie body also can look like a Pink Panther liao!
Then the next morning baru they know the nightmare just began. 
that's the reason why on that night you can see most of the ugly girl come out and they like to dress up and look like Orang Mati loh!! Satu kali go look ugly.... so cannot see is not pretty mah. hahahaha
Then the funny thing is in the X'mas Party those ugly betty all gone and you never see them and you have to wait until next year Halloween night then you can see them again!
That's the only night can lelong the old stock....One year one night O... what's ghost also come out lah!

Ok back to the tropic "Why Halloween have to use Pumkin?" 
Ya loh..... Kenapa? Why ah? 為甚麼?
Why Halloween have to use pumpkin one?
I don't know...... 
That's why I asking people in the FB. Most of then also don't know why. Someone even ask me back why not using Durian, Rambutan or Watermelon?
Hey friends... how I know O!!! Why have to use Pumpkin already make me sak sak and yet you people ask me back why not using the local fruits... apa lah you people!
Then after I do some homework and search in Google and I found the answer here
The answer I took from the and the story is like this and is very interesting. 
700,000 immigrants came to America in the 1800s during the Irish Potato Famine, bringing with them the traditions of Halloween and the use of Jack O Lanterns. Traditionally, the lantern was carved from a turnip, potato, or beet and lit with a burning lump of coal or a candle. These lanterns represented the souls of the departed loved ones and were placed in windows or set on porches to welcome the deceased. They also served as protection against malevolent spirits or goblins freed from the dead. Turnips and gourds were not as readily available in the Americas so the pumpkin was used and found to be quite an adequate replacement. The pumpkin jack o- lantern has been an essential part of Halloween celebrations since the Victorian days and today is a universal symbol of Halloween.
There are many lore's and legends surrounding the origin of the Jack O Lantern. The most popular tale is that of a Nowell Irishman name Jack. Well known for his drunken meanness, Jack got so intoxicated on a Halloween that his soul began to leave his body. The Devil saw an opportunity to claim a victim and promptly came to earth. Jack was desperate to avoid his fate so he begged the Devil to allow him one last drink. The Devil consented but stated that Jack would have to pay for his drink because the Devil carried no money. Jack claimed to only have a sixpence left and asked that the Devil assume the shape of a sixpence to pay for the drink. Then, tab paid, the Devil could change back to himself.
The Devil considered the request reasonable and changed himself into a sixpence. Jack immediately grabbed the coin and put it in his wallet, which had a cross shaped catch. The Devil was unable to get out and began ranting and cursing. They then made a deal that the Devil would be released if he agreed to let Jack alone for one year. The Devil agreed and Jack set forth to reform is behavior over the next year. It wasn't long before Jack slipped back into his mean, drunken ways and the next All Hallows Eve the Devil appeared to Jack and demanded his soul. Once again, Jack was desperate to save himself and did so by tricking the Devil.
He suggested to the Devil that he may want one of the delicious apples hanging in a tree nearby. He offered to allow the Devil to climb on his shoulders to reach the apples. Once the Devil was in the tree, Jack pulled out a pocket knife and carved a cross in the tree trunk. The Devil could not get out of the tree. Furious and desperate, the Devil offered Jack ten years of peace in exchange for freeing him. Jack insisted that The Devil never bother him again and he would be freed. The Devil resentfully agreed. Jack then returned to his old ways but before the next Halloween, his body gave out and he passed.
He was turned away at the gates of Heaven because of the meanness in his life. The Devil refused him at the gates of hell, stating that he would never bother him again and told him to return from whence he came. To help Jack see on his journey, the Devil threw him a burning lump of coal from hell. Jack put the ember inside of a turnip and it has been Jack's light on his eternal wanderings ever since. To protect oneself from Jack on All Hallows Eve, jack o lanterns were placed on porches and in windows, in hopes that Jack would take the light if needed instead of bothering anyone.

(articles copy from the