Panicle and Shoot Blight of Pistachio: A Major Threat to the California Pistachio Industry

Abstract

Introduction Pistachio cultivation dates back to the Holy Lands of the Middle East, where they grew wild in the high desert regions. The history of pistachios includes aspects of royalty, perseverance, and pride. Legend has it that lovers met beneath the trees to hear the pistachios crack open on moonlit nights for the promise of good fortune. A rare delicacy, pistachios were a favorite of the Queen of Sheba, who demanded all her land's production for herself and her court. The royal nut was imported by American traders in the 1880s, primarily for U.S. citizens of Middle Eastern origin. Some 50 years later, pistachios became a popular snack food, introduced in vending machines. These imported nuts were dyed red to draw attention and to cover stains from antiquated harvesting and drying techniques. The inception of the California pistachio industry occurred in 1929, when the American plant scientist William E. Whitehouse spent a lonely six months in Persia (Iran), collecting seed and going through piles of product to find the most distinctive pistachios. He returned with 20 pounds of seed to start a breeding program. With pistachios requiring from 7 to 10 years to mature, it was 1950 before a successful cultivar emerged from that program. The variety was named Kerman for the famous carpet-making city near where the original seed was collected by Dr. Whitehouse. University of California scientists then budded (grafted) the Kerman to more vigorous rootstocks. Thus the dream of a California pistachio industry became a reality. Word of the new crop spread, plantings expanded throughout the state in the 1960s, and the first commercial crop of 1.5 million pounds was harvested in 1976 from less than 1500 acres. By 1990, approximately 50,000 bearing acres yielded 120 million pounds, by 2000 approximately 75,000 acres yielded a total of 240 million pounds, and by 2002 a total of 300 million pounds were produced. With their acreage and production expanding, California pistachio growers united in their efforts to promote the industry. In 1981 the California Pistachio Commission (CPC) was established to provide support through public relations, marketing, and production research. By 2000, the CPC became one of the most successful agricultural industries in California. The CPC is funded by an assessment (cents) per pound of pistachios produced in the State. Pistachio is a dioecious plant with fruit drupes born in taxianthies called panicles (clusters).