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

2. Grape Fruit Diseases
A
Lecture To ToT trainees ( FFS)
By
Mr. Allah Dad Khan
Provincial Coordinator IPM KPK
MINFAL Pakistan

3. Citrus canker
Xanthomonas axonopodis
Symptoms
Citrus 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

15. Stubborn disease
Spiroplasma 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

16. Blast
Pseudomonas 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

17. Anthracnose
Colletotrichum 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

18. Brown rot
Phytophthora 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

30. Tristeza disease
Citrus 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

34. 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 asiativus
Candidatus Liberibacter africanus
Candidatus Liberibacter americanus