Grape Fruit Diseases A
Lecture To ToT trainees ( FFS) By
Mr. Allah Dad Khan Provincial Coordinator IPM
KPK MINFAL Pakistan
Citrus cankerXanthomonas axonopodis
SymptomsCitrus canker on grapefruit
Raised lesions on leaves, often at leaf margin or tip; lesions may also be present on twigs and fruits; young lesions are usually surrounded by yellow halo; depressed brown craters formed from collapse of lesions
Cause Bacterium
Stubborn diseaseSpiroplasma citri
Symptoms Stunted trees; leaves
shorter and broader, cupped and upright; may be chlorotic or have a mottled appearance; stunted, malformed fruits and low yield
Cause Bacterium
BlastPseudomonas syringae
Symptoms Water-soaked or black
lesions on leaf petioles;which rapidly expand along the leif midrib; cankers on twigs and branches; twigs may be girdles and die; leaves turning black and dying; black lesions may be present on fruit
Cause Bacterium
AnthracnoseColletotrichum gloeosporioides
Anthracnose symptoms on grapefruit
Symptoms Dieback of twigs;
premature leaf drop; dark staining on fruit; leaves and twigs covered in dark spores
Cause Fungus
Brown rotPhytophthora spp
Symptoms Water-soaked lesions on
fruit close to maturation; leather tan to dark brown lesions on fruit; lesions with a pungent smell; leaves, twigs and flowers may be turning brown
Cause Oomycete
Tristeza diseaseCitrus tristeza virus (CTV)
Pits in trunk of grapefruit tree infected with tristeza disease
Symptoms Light green foliage; poor new
growth; leaves may be dropping from tree; young trees blooming early; severely infected trees are stunted and bushy in appearance with chlorotic leaves and brittle twigs; some strains of the virus cause elongated pits in the trunk and branches which give the wood a rope-like appearance
Cause Virus
Huanglongbing (Citrus greening, Yellow dragon disease)
Symptoms of huanglongbing on grapefruit leaves
Symptoms Yellowing of one limb or one
area of canopy; yellowing of leaf veins; blotchy mottling on leaf blades; twig and limb dieback; fruits dropping prematurely; small upwardly pointing leaves; small, misshapen fruit; fruit very bitter
Cause Bacteria
Candidatus Liberibacter asiativusCandidatus Liberibacter africanusCandidatus Liberibacter americanus