The author discusses how in the late 1940s and into the 1950s--an era of both Communist hysteria and significant Communist threat within the United States (US)--pumpkin connoted scandal, as in the infamous pumpkin papers.
"Trends. From Pumpkin Papers to Pumpkin Capers: Washington Scandals,"
International Bulletin of Political Psychology: Vol. 4
, Article 5.
Available at: http://commons.erau.edu/ibpp/vol4/iss3/5