Anthracnose disease of citrus has mainly been attributed to C. gloeosporioides and C. acutatum which are considered mainly as foliar and fruit pathogens. Futch and David P.H. Anthracnose may blemish the rind tissue of mature Valencia and navel oranges, grapefruit, and occasionally lemon. Blister-like lesions on leaves and fruit start small and expand as the disease progresses. •Twig dieback Photo Credit: Tripti Vashisth, UF/IFAS CREC; A Guide to Citrus Nutritional Deficiency and Toxicity Identification, S.H. Citrus canker, caused by a bacterial pathogen, is a serious disease of most citrus varieties. Dieback, common symptom or name of disease, especially of woody plants, characterized by progressive death of twigs, branches, shoots, or roots, starting at the tips. What Can I Do? The causal agents of this disease were identified as species of Colletotrichum, which are well-known pathogens of citrus and other crops causing anthracnose diseases. Tucker Fruit will often drop prematurely from infected trees. Citrus red mites feeding and harsh weather can result in heavy leaf drop, twig dieback, and death of large limbs. Entire tree. Shoot and Twig Dieback of Citrus Recently, an outbreak of shoot and twig dieback disease of citrus has been occurring in the main citrus growing regions of the Central Valley of California (Fig 1). Staghead is a slow dieback of the upper branches of a tree; the dead, leafless limbs superficially resemble a stag’s head. Citrus greening, also known as Huanglongbing or HLB, is one of the worst citrus diseases in the world. Infected plants are usually symptomless. Bacterial dieback Apple, citrus, stone fruits, and pear are susceptible to bacterial blast, blight, and cankers, all of which are caused by Pseudomonas syringae. This pathogen kills flower clusters and nearby leaves, along with twig tips. The bacterium grows and multiplies in diseased plant parts—all aboveground parts of the citrus tree are susceptible. Dying leaves and twigs become covered with dark fungal spores by which the pathogen spreads. 1). Shoot and Twig Dieback of Citrus Recently, an outbreak of shoot and twig dieback disease of citrus has been occurring in the main citrus growing regions of the Central Valley of California (Fig 1). The disease causes necrotic lesions on leaves, stems, and fruit. Scouting. Citrus tatter leaf capillovirus, (syn. Fireblight is another bacterial infection that causes twig dieback. Severe infestation can cause defoliation, premature fruit drop, twig dieback, general tree decline, and very bad blemishes on fruit. The fruit a tree does produce is usually small, lopsided, and underdeveloped. ecently, an outbreak of shoot and twig dieback disease of citrus has been occurring in the main citrus growing regions of the Central Valley of California (Fig 1). Later symptoms of citrus greening include twig dieback and decreased fruit production. The Citrus red mite is a major pest of citrus worldwide causing considerable damage on lemon and grapefruit, and to a lesser extent on orange and tangerine. Citrus canker causes premature leaf and fruit drop, twig dieback, general decline, and blemished fruit (Fig. However, when symptoms are produced, one can observe leaf yellowing, leaf deformation, twig deformation, stunting, overblooming, and premature fruit drop. Symptoms of anthracnose on citrus include twig dieback, premature leaf drop, dark staining on fruit and postharvest fruit decay. Citrange stunt virus) Area(s) affected. The association of C. karstii with citrus twig and shoot dieback in California represents a significant finding since C. karstii appears now to be a new pathogen of citrus in the United States. Signs/Symptoms. Regularly scout citrus for signs of greening.