in an open or perforated plastic bag. Pests and diseases Cottony cushion scale The first major pest that attacked orange trees in the United States was the cottony cushion scale (Icerya purchasi), imported from Australia to California in 1868. Within 20 years, it wiped out the citrus orchards around Los Angeles, and limited orange growth throughout California. In 1888, the USDA sent Alfred Koebele to Australia to study this scale insect in its native habitat. He brought back with him specimens of Novius cardinalis, an Australian ladybird beetle, and within a decade the pest was controlled. Citrus greening disease The citrus greening disease, caused by the bacterium Liberobacter asiaticum, has been the most serious threat to orange production since 2010. It is characterized by streaks of different shades on the leaves, and deformed, poorly colored, unsavory fruit. In areas where the disease is endemic, citrus trees live for only five to eight years and never bear fruit suitable for consumption. In the western hemisphere, the disease was discovered in Florida in 1998, where it has attacked nearly all the trees ever since. It was reported in Brazil by Fundecitrus Brasil in 2004. As from 2009, 0.87% of the trees in Brazil's main orange growing areas (São Paulo and Minas Gerais) showed symptoms of greening, an increase of 49% over 2008. The disease is spread primarily by two species of psyllid insects. One of them is the Asian citrus psyllid (Diaphorina citri Kuwayama), an efficient vector of the Liberobacter asiaticum. Generalist predators such as the ladybird beetles Curinus coeruleus, Olla v-nigrum, Harmonia axyridis, and Cycloneda sanguinea, and the lacewings Ceraeochrysa spp. and Chrysoperla spp. make significant contribution to the mortality of the Asian citrus psyllid, which results in 80–100% reduction in psyllid populations. In contrast, parasitism by Tamarixia radiata, a species-specific parasitoid of the Asian citrus psyllid, is variable and generally low in southwest Florida: in 2006, it amounted to a reduction of less than 12% from May to September and 50% in November. In 2007, foliar applications of insecticides reduced psyllid populations for a short time, but also suppressed the populations of predatory ladybird beetles. Soil application of aldicarb provided limited control of Asian citrus psyllid, while drenches of imidacloprid to young trees were effective for two months or more. Management of citrus greening disease is difficult and requires an integrated approach that includes use of clean stock, elimination of