Appendix E
Significant Citrus Diseases Other Than Huanglongbing
Disease Name |
Causal Organism/Vector |
Distribution |
Management/Control |
Reference |
Additional Information |
Systemic Diseases |
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Citrus Variegated Chlorosis |
Xylella fastidiosa |
Southern Brazil; Argentina; Costa Rica |
Propagation of healthy budwood; pruning infected limbs of newly-affected trees; removal of affected trees in young plantings. |
Chang et al., 1993; Hartung et al., 1994; Timmer et al., 2003 |
Potentially important anywhere in the world. |
Transmitted by sharpshooters and other xylem-feeding leafhoppers |
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Stubborn Disease |
Spiroplasma citri |
Arid citrus regions, such as parts of California and Arizona, North Africa, and the Middle East |
Avoiding infection in nurseries and young plantings. |
Roistacher, 1991; Timmer et al., 2003 |
Unlikely to be a problem in humid areas where environmental conditions for spread do not exist. |
Transmitted by several species of leafhoppers |
Disease Name |
Causal Organism/Vector |
Distribution |
Management/Control |
Reference |
Additional Information |
Tristeza Decline and Stem Pitting |
Citrus Tristeza Virus (CTV) |
Asia, South America, South Africa, Australia, Spain, Israel, Southern Italy |
Use of tolerant rootstocks and scion varieties; cross protection with mild, strains of CTV to delay infection/reduce severity of stem pitting. |
Roistacher, 1991; Garnsey, 2005; Hilf, 2005; Costa and Müller, 1980 |
Decline strains spreading in the Mediterranean; the importance of stem pitting increases with spread of Toxoptera citricidus, the most efficient vector. |
Transmitted by several species of aphids |
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Citrus Sudden Death or Morte Subita dos Citros |
Virus (member of Marafivirus) |
Brazil (southern Minas Gerais and northern São Paulo) |
Use of tolerant rootstocks (such as Cleopatra and Sunki mandarins, Carrizo citrange, and Swingle citrumelo) instead of Rangpur lime. |
Román et al., 2004; Bassanezi et al., 2003 |
Conditions outside of Brazil may not favor development of this disease. |
Graft transmissible; vector has not been identified |
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Citrus Blight |
Unknown |
The Americas, Australia, South Africa |
Replacement of affected trees with trees on tolerant rootstocks; no known cure for this disease. |
Derrick and Timmer, 2000; Timmer and Bhatia, 2003 |
Most important in Florida and Brazil; potential for development elsewhere uncertain. |
Transmissible by root- piece and tree-to- tree root grafts |
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Leprosis |
Bacilliform Virus |
South America and Central America |
Control of its mite vector using acaricides. |
Roistacher, 1991; Bastianel et al., 2006 |
Only locally systemic in infected areas of the tree. |
Transmitted by Brevipalpus mites |
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Witches' Broom Disease of Lime (WBDL) |
Phloem- limited phytoplasma |
Oman; United Arab Emirates; Iran |
WBDL is only confined to limes; sweet orange, mandarin and grapefruit are apparently resistant. |
Garnier et al., 1991; Roistacher, 1991 |
Dangerous disease for western Mexico and other producing areas of Mexican lime. |
May be transmitted by Hishimonus phycitis leafhoppers |
Disease Name |
Causal Organism/Vector |
Distribution |
Management/Control |
Reference |
Additional Information |
Viroids |
Citrus exocortis viroid (CEVd); Cachexia CVdI, CVdII; CVdII, CVdIV |
Wherever citrus is grown |
Eliminated by certification programs; sterilization of pruning tools and budding knives. |
Duran- Villa et al., 2000 |
Have been largely eliminated by budwood certification programs; important primarily on rootstocks such as trifoliate orange and its hybrids and Rangpur lime. |
Bacterial and Foliar Fungal Diseases |
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Citrus Canker |
Xanthomonas citri subsp. citri |
Asia; southern Brazil, Argentina; Uruguay; Caribbean; Florida |
Quarantine and eradication where not endemic; in endemic areas, windbreaks to reduce severity and copper products to prevent fruit infection. |
Civerolo, 1984; Koizumi, 1985; Graham and Gottwald, 1991; Gottwald et al., 2001; Schubert et al., 2001; Graham et al., 2004 |
Not only important for fresh fruit; causes significant leaf and fruit drop. |
Citrus Black Spot |
Guignardia citricarpa (Anamorph: Phyllosticta citricarpa) |
Widespread in the humid to semi- arid citrus-growing areas in the Southern Hemisphere |
Controlled primarily by fungicide applications (benzimidazoles, copper products, dithiocarbamates, or strobilurin) in the summer. |
Peres and Timmer, 2003; Timmer et al., 2004; |
Not only important for fresh fruit; causes significant fruit drop as well. |
Pseudocercospora Fruit and Leaf Spot |
Pseudocercospora anglonensis |
Angola; Mozambique; Yemen; Western and Southern Africa |
Preventive applications of copper fungicides, chlorothalonil, flusilazole, or propineb. |
Seif and Hillocks, 1997; Timmer et al., 2004 |
Not only important for fresh fruit; causes significant leaf and fruit drop. |
Disease Name |
Causal Organism/Vector |
Distribution |
Management/Control |
Reference |
Additional Information |
Greasy Spot |
Mycosphaerella citri and other Mycosphaerella spp. |
Uncertain; widespread in the Caribbean area; some problems occur elsewhere and may due to other species of Mycosphaerella. |
Foliar applications of petroleum oils or various fungicides. |
Mondal and Timmer, 2006 |
May cause severe defoliation and fruit blemishes, especially on grapefruit and lemons. |
Sweet Orange Scab |
Elsinoe australis |
South America |
Application of sterol-inhibiting fungicides, ferbam, benzimidazoles, strobilurins, or copper products. |
Timmer et al., 2004 |
Only important for fresh fruit production. |
Postbloom Fruit Drop |
Colletotrichum acutatum |
Western Hemisphere |
Application of fungicide such as benzimidazoles, strobilurins, captan, maneb, or ferbam. A computer assisted system has been developed for timing fungicide applications. |
Timmer et al., 1994; Peres et al., 2005 ; Timmer and Brown, 2000 |
Only important where rainfall is high during bloom. |
Alternaria Brown Spot |
Alternaria alternata |
First described in Australia in 1903; Mediterranean; Caribbean Basin; South Africa; South America |
Minimize leaf wetness (avoiding overhead irrigation); use of disease-free nursery trees; avoiding excessive nitrogen fertilization and irrigation; application of foliar fungicides. alter-rater, a predictive system, has been developed to time sprays. |
Timmer et al., 2003; Akimitsu et al., 2003 |
Only affects some tangerines and hybrids; spreading in semi-arid areas. |