- HUANGLONGBING: DEVASTATING DISEASE OF CITRUS 319
processing industry and accounts for essentially all U.S. orange juice
production. Brazil exports about 90% of its juice production includ-
ing a considerable amount to the United States, whereas only 10% of
Florida’s production is exported internationally.
Florida grapefruit is grown predominately for fresh fruit but a con-
siderable portion of the crop is processed for juice. Florida is the largest
U.S. producer, commanding about two-thirds of the total U.S. produc-
tion. Florida produces about 30% of the world’s grapefruit with Mexico,
Cuba, and Turkey contributing significantly to world production. Japan
is the largest importer of fresh Florida grapefruit and Canada is the lead-
ing importer of Florida fresh oranges and specialty citrus fruit (USDA,
NASS 2015). Although fresh fruit and juice are the two citrus products
most common to consumers, by-products of the citrus juice industry are
the source of important products used in the flavor and fragrance indus-
try (peel oil), for cleaning products (limonene), pectin, animal feed, and
phytonutrients such as flavonoids (Maier et al. 1980; Braddock 1999; Li
et al. 2006a).
The U.S. citrus industry farm gate value is estimated at $3.5 billion,
and economic impact of citrus, including processing, on the Florida
economy is estimated to be $9 billion (USDA, NASS 2015). Of the four
citrus-producing states in the United States, Florida is by far the largest
with approximately 202,343 ha. California has approximately 109,265
ha of citrus in production, with most land devoted to navel oranges,
lemons, and increasingly mandarins and mandarin hybrids. Essentially
100% of California citrus goes into the fresh market. Texas has about
10,926 ha of grapefruit in production for the fresh market, and Arizona
has about 5058 ha of citrus production, with it being mostly lemons
(C. limon). Florida citrus has been declining in the last few years mostly
due to Huanglongbing (HLB), especially since 2012, and worldwide pro-
duction and consumption has declined since 2005 (Fig. 7.1).
II. HUANGLONGBING DISEASE
Currently, HLB, a citrus disease associated with an insect-vectored bac-
terium, is the greatest threat to the sustainability of worldwide citrus
industries (Bove 2006; Gottwald 2007; Bov ́ ́e 2014). Over the years, the
disease now recognized as HLB, was known by various names including
Huanglongbing in China; likubin in Taiwan; dieback in India; leaf mot-
tle in the Philippines; vein phloem degeneration in Indonesia; and yel-
low branch, blotchy-mottle, or greening in South Africa (da Grac ̧a 1991;
Bove 2006). In 1995, the International Organization of Citrus Virologists ́