My Citrus Tree – Disorders

Tristeza is vectored by several species of aphid the most efficient being the brown citrus aphid Toxoptera citricida (Kirklady). Where T. citricida does occur, Aphis

Sweet orange scab forms spores on the surface of the scab pustules. This species of scab attacks mainly fruits. The conidia ( asexual spores) are

Psorosis is transmitted by grafting. There is some evidence of natural spread, possibly by Olpidium brassicae which transmits other ophioviruses, or by an aerial vector.

Pseudocercospora angolensis is a fungus that requires moisture for infection and the production of wind-borne conidia. Other than by wind, conidia can be transported on

Phytophthora is a water mold (Class Oomycetes, formerly a fungus-like protist) that is found throughout the world. Under favorable conditions (high moisture and temperature) it

Melanose is a saprophyte that completes its lifecycle on dead twigs. The disease severity is determined by the amount of inoculum on dead wood in

Citrus leprosis virus (CiLV) is transmitted by the false spider mites in the genus Brevipalpus (Acari: Tenuipalpidae). Brevipalpus mites occur on citrus around the world

Huanglongbing (HLB) is presumptively caused by a phloem limited bacteria. In citrus there are three forms of concern, the Asian, African and American forms. The

The major source of inoculum for greasy spot are wind-dispersed sexual spores (ascospores) produced during periods of wetness on decomposing fallen leaves. The disease cycle

CVC is a systemic disease that only survives in plant xylem or within its vector. X. fastidiosa has been shown to move from seed to

CSD is caused by Spiroplasma citri, a phloem-limited, cell-wall-less bacterium. S. citri is transmitted in a propagative, circulative manner by several leafhoppers including Circulifer tenellus

Conidia are produced on the surface of scab pustules. These spores spread to new susceptible tissue. There are two kinds of spores, clear oval shaped