(IPPM) in Vegetables - Vegetableipmasia.org

Resource Manual on IPPM in Vegetable
World Education Philippines, Inc.
Powdery
mildew
Leveillula
taurica (Lev)
Arnaud
Oidiopsis
taurica Tepper
Bacterial Spot
Xantomonas
campestris pv.
vesicatoria
Alternaria leaf
spot
Alternaria
brassicae
Legumes
Parsley
solanaceous
Crucifers
Cucurbits
brassicae
fast on older leaves and
progress then on younger
leaves as the disease
develops.
· The spots soon become
roughly circular and have
gray centers surrounded by
darker margins. Later the
centers show tiny dark specks
where spores of the fungus
are produced. The leaves may
become dry and may later fall
off the plant.
· Initial symptoms are small,
white powdery spots that first
appear on the upper surface
of the leaflets and soon
become evident on both
surfaces.
· Affected tissues turn yellow.
In serious cases, the mildew
covers the entire leaf until it
shrivels and dies. The
disease progresses from the
older to younger leaves. The
pathogen also affects stem,
petioles and floral parts.
· Leaf lesions begin as watersoak,
circular to irregularlyshaped
spots that become
necrotic with brown centers
and chlorotic borders.
· More numerous on young
than old leaves. Lesions are
slightly sunken on the upper
leaf surface and slightly
raised on the lower surface.
Lesions sometimes coalesce
and severely infected leaves
turn yellow and drop.
· Fruit symptoms start as
water-soaked brown dots and
then become raised, wart-like
in appearance surrounded by
a lighter halo. Narrow,
elongated lesions or streaks
may develop on stems.
· Symptoms of alternaria leaf
spot usually appear on the
older leaves of the cabbage
plant. The spots begin as
black pinpoint-sized spots
and enlarge to distinct brownblack
leaf spots of 1-2 cm
diameter with concentric
rings and sometimes yellow
area around the spot.
· The concentric rings contain
avoided by using pathogen-free
seeds, crop rotation and
sanitation. Cool weather slows
disease development. Use of
fungicides can reduce the rate of
disease increase.
· Treat seeds with hot water before
sowing.
· The use of sprinkler irrigation
and fungicidal spray can help in
reducing the development of the
disease.
· The bacterium can be seed-borne
and persists in crop debris and
weeds. Warm temperatures,
sprinkle irrigation or heavy rains
enhance the severity of the
disease. Seed cleaning along
with crop rotation, helps in the
prevention of disease outbreaks,
while copper compound sprays
reduce the rate of disease
development.
· To prevent the occurrence of the
disease, use clean seed that is
treated in hot water of 50oC for
30 minutes. This will kill spores
that are attached to the seed.
· Sanitation, destruction of
cruciferous weeds and crop
rotation also help reduce the
development of the disease.
When planting, orient rows in the
direction of prevailing winds for
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