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

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

3. SYMPTOMS
 Small irregularly shaped or roughly
circular dark brown lesions with
darker brown border on upper surface
of leaves; lesions may also be present
on stems and fruit; under humid
conditions, fungus may sporulate and
gray tufts of mycelium may be visible
in the center of lesions; lesions may
coalesce to form large necrotic patches
 Cause
 Fungus
 Comments
 Infection of leaves occurs during wet
conditions when temperatures are
between 13 and 25°C (55-77°
F); disease can be spread by splashing
water

4.  Wilt in guava is caused by a fungus Fusarium solani or Cephalosporium
sp. or Rhizoctonia sp. The symptoms appear on the infected trees many
months after their roots have been attacked by the fungi. Sparse foliage,
yellowing of leaves and tree wilting are the symptoms. Before wilting tree
may flower profusely and set fruit which remain small. Overbearing is
due to stress of damaged roots.
 In the roots the cambium between the bark and wood show dis-
colouration. Replant trees in the same pits bear fruit for few years and are
again attacked by the fungi. Refilling of the gaps should be done after
treating the soil with fungicides.
 Control:
 Plant guava m well drained fields. Avoid flooding the guava field while
applying irrigation. Apply 15 g Bavistin to each plant trunks in 2 litre of
water.
 (i) Uproot and burn the wilted trees along with all roots.
 (ii) Drench the soil in the pit with 2 percent formalin solution and cover
with sarkanda and old wetted gunny bags. Expose the soil for 14 days
and replant healthy guava plants.
 Guava Wilt:

5. SYMPTOMS
 Orange, rust-colored, dense, silky tufts on
both upper and lower surfaces of leaves
which turn reddish-purple in color as they
mature; if tufts are scraped away, a thin
gray-white or dark-colored necrotic spot
remains on the leaf; bark on twigs and
branches may be cracked; young stems and
fruit may also be attacked
 Cause
 Alga
 Comments
 Wet, humid conditions promote spread of
the disease; zoospores can be spread by
splashing water
 Management
 Ensure trees receive adequate fertilization,
irrigation and and are properly pruned to
avoid stress on the plants and promote air
circulation through the canopy; periodic
applications of a copper based fungicide is
usually enough to control the disease

6. SYMPTOM
 s
 Sunken, dark colored lesions on mature fruit
which may become covered in pink spores;
lesions coalesce to form large necrotic
patches on surface of fruit
 Cause
 Fungus
 Comments
 Disease emergence favors warm, wet
weather; spread easily during wet weather
by water splash
 Management
 The primary method of controlling the
disease is to plant resistant guava cultivars;
both systemic and non-systemic fungicides
are effective at controlling the disease and
are usually applied shortly before flowering
and during fruit develpment

7. SYMPTOMS
 Orange to red pustules appearing on leaves,
young shoots, flowers and/or fruit; leaves
distorted; defoliation of tree; reduced
growth; circular lesions on fully expanded
leaves with dark borders and yellow halos
 Cause
 Fungus
 Comments
 Disease emergence favored by warm
temperatures and high humidity
 Management
 Primary method of controlling disease is
usually the application of appropriate
fungicides; cultural practices that may
reduce the incidence of the disease include
good sanitation practices and adequate
fertilization, irrigation and pruning of trees
