Guava diseases ppt

PERSENTATION ON
DISEASES OF GUAVA
PRESENTED BY
SUSHEEL KUMAR
Id. No. 48008
M.Sc. 3rd YEAR
VEG. SCIENCE

OCCURRENCE AND
IMPORTANCE
 Wilt is a pernicious disease of guava in India.
In India the disease was first recorded near Allahabad in
1935 . The infection was reported 15 -30 %.
The disease is a serious threat to guava cultivation in U.P.
In West Bengal it reduces the yield in affected orchard by
80% .
The disease is also prevalent in Haryana Rajasthan , A.P ,
Punjab and M.P.
It has forced uprooting of about 150 acre of guava orchard
in Panjab and 300 acres in Haryana during 1971-81.

CAUSAL ORGANISM
 The exact cause of the disease is still not fully understood but
the pathogens viz. Fusarium oxysporum f. sp. psidii (Prasad,
Mehta & Lal), Rhizoctonia spp. (Taub.) and various pathogens
are reported by different workers may be the incitant of the
disease.
Survival and spread:
 Through movement of plants containing sick soil in virgin
areas.
 Short distance spread is by water.
 Root injury predisposes wilt disease.

CONTI…..
Favourable conditions:
 High rainfall during August/ September.
 Stagnation of water in guava field for long duration.
 Maximum and minimum temperature ranges 23-32 °C with
76% RH are conducive.
 Lack of timely application of suitable control measures.
 There is severe incidence of wilt in alkaline soils at pH ranging
from 7.5 to 9.0 or in lateritic soils at pH 6.5 .
 Guava seedlings are more susceptible to F. solani as well as F.
oxysporum f.sp. psidii than older plants of 3 years age.
 On the other hand researchers reported that F. solani could
infect guava plants from 1-month-old to more than 4 years old.

SYMPTOMS
The leaves shed of premature , fruit
size remain smaller, bare twig fail to
develop new leaves and flower dry
up.
 Browning and wilting of leaves
from tip.
Discolouration of stem and death
of branches and then the whole tree
dry up.
 The inner part of stem and root
upto cambium and vascular tissues
show a distinct discolouration.

MANAGEMENT
 Proper sanitation.
 Soil solarization.
 Uprooted and burnt wilted plants.
 Severe pruning followed by a drench with .2 % Benlate
or Bavistine 4 times in a year.
 Injection guava plant with 0.1 % water soluble 8-
quinolinol sulphate may provide protection against wilt
for at least 1 year.
 Use of resistant and tolerant varieties like , Allahabad
Safeda , Dholka , Sindh etc.

OCCURRENCE AND
IMPORTANCE
 Anthracnose is most common and important disease of guava
in India, patricularly in U.P. ,Punjab and Karnataka.
 It first reported from Saharanpur(U.P).
 The disease also occur in Thailand , Philippines ,Bangladesh
and Pakistan.
 It also cause serious postharvest rotting of guava fruits.

CAUSAL ORGANISM
Anthracnose is caused by Gloeosporium psidii,or colletotrichum psidii.
 Infection spreads by wind borne spores develop on dead leaves, twigs and
mummified fruits in the orchard.
 Dense canopy is congenial for germination of spores due to high moisture
condition.
 Movement of planting material through infected foliage.
 Transportation of fruits from high disease prone area.
 Closer planting without canopy management
 The acervuli with pink spore masses are produced in moist weather on dead
twig and mumified fruits.
 Dew or rains encourages spore production and its dispersal around canopy.
 Temperature between 10 to 35oC with best 24 to 28oC.

SYMPTOMS
 Fruit and leaf infection is generally seen
during rainy season crop. Pin-head spots are
first seen on unripe fruits, which gradually
enlarge.
Spots are dark brown in colour, sunken,
circular and have minute black stromata in the
center of the lesion, which produce creamy
spore masses in moist weather.
Several spots coalesce to form bigger lesions
.
The infected area on unripe fruits become
corky and hardy, and often develops cracks in
case of severe infection.
Unopened buds and flowers are also affected
which cause their shedding.
On leaves, the fungus causes necrotic lesions
usually ashy grey and bear fruiting bodies at
the tip or on the margin .

MANAGEMENT
 Three applications of Bordeaux mixture and Perenox (0.22
and 0.33%) after removal of dead twigs.
 Spray of copper oxychloride and cuperous oxide (.3%) at
weekly intervals effectively reduce the infection.
 Apply Carbendazim 1gm/litre during June-September.

OCCURRENCE AND
IMPORTANCE
 Phytophthora fruit rot cause extensive damage to
rainy season crop of guava in Maharastra , Karnataka,
Rajasthan ,Panjab and Haryana.
 Sohni and Shridahar (1971) recorded 16.3 % loss to
the crop before harvest in Mysore.
 The post harvest loss are much higher.

CAUSAL ORGANISM
 Phytophthora nicotiana var. parasitica cause fruit rot of guava.
 Rain and the wind are conducive for spread.
 The pathogen produces a great number of sporangia and spores on the
surface of diseased tissues principally when the temperature is near
25°C and this is an important sources of inoculum in the development
of epidemics.
 Spores spread from the infected plant material or soil by rain splashes.
 Cool, wet environmental conditions with high soil moisture favour
disease development.
 High humidity, temperature from 28-32oC (25 oC), poorly drained soils
and injuries are favourable for initiation of disease.
 Close plantation.

SYMPTOMS
The disease starts at blossom and stem
end or even anywhere on the surface of well
developed fruits.
The skin of the fruit below the whitish
cottony growth becomes a little soft, turns
light brown to dark .
 Young, small and unripe fruits are more
prone to infection. They become hard and
woody.
On leaves the disease starts as small
brown spots at margin or tip, spread fast
and affected the entire lamina.

MANAGEMENT
 Soil solarisation .
 Destroy plant debris.
 Sprays of Bordeaux mixture , copper oxychloride (.2%) and
Dithane- Z- 78 (.2%) for control of guava fruit rot.
 Six spray of Dithane- Z- 78 (.2%) at one month interval from
June to November.

Guava diseases ppt

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Guava diseases ppt