Grape fruit diseases A lecture By Allah Dad Khan Provincial Coordinator IPM KPK MINFA

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