This document discusses 5 diseases that affect sapota trees:
1. Leaf spot caused by Phaeopleospora indica, which causes circular brown spots on leaves. It is managed by spraying fungicides.
2. Pestalotiopsis leaf spot caused by Pestalotiopsis versicolor, which causes small reddish-brown spots on leaves that enlarge and develop gray centers.
3. Flat limb caused by Botryodiplodia theobromae, which causes branches to become flat and twisted and leaves to become small and yellow, reducing fruit production.
4. Sooty mould caused by Capnodium versicolor, which grows on insect excretions and causes
2. 1. Leaf spot / Phavophleospora leaf spot
• Phaeopleospora indica: Initially circular spots pinkish in colour
appear which gradually turn brownish in colour.
• Centre of the spot is whitish grey coloured and number of spots are
more on leaves.
4. 2. Pestalotiopsis leaf spot
• Pestalotiopsis versicolor (Syn: Pestalotia
versicolor, P. sapotae and P. podocarpi)
5. Symptoms
• Small, reddish brown specks on leaf lamina.
• Spots enlarge, become circular measuring 1 to 3 mm in diameter
• Fully developed spots show grayish centre and dark brown to
reddish margin
• Minute black fruiting bodies (pycnidia) are seen in the center of
spots
6. 3. Flat limb
• Botryodiplodia theobromae
• First reported from Maharashtra and Gujarat
by Khurana and Singh in 1972
7. Symptoms
• Branches of affected trees become flat and twisted.
• Leaves become thin, small and yellow.
• Cluster of leaves and flowers on affected twigs.
• Flowers remain infertile.
• If fruits are set, they are undersized, hard and fail to ripen.
• Foliage and fruits fall prematurely.
9. Symptoms
• Disease severity increases in increased
population of leaf hoppers, aphids and other
insects.
• Black superficial growth on entire surface of
leaves, fruits and twigs.
• Fungus is not a parasite. It grows on the
excreta and honey secretions of insects.
• Under dry spell such affected leaves curl &
shrivel. During flowering time the
appearance of the disease results in reduced
fruit set.
• Sooty mass is a superficial growth of the
fungus and it multiplies on insect secretions.
Impact of this disease on host is
photosynthesis activity and yield decreases.
10. Mode of spread
• Primary source of inoculum: Dormant mycelia
• Secondary source of inoculum: Air borne conidia: Spread:
Insects, Aphids, wind.
Epidemiology:
• Temperature 28-32 ⁰C, 85-90% RH, Warm Weather and
susceptible host.
11. Management
• Sprays of wettable sulphur 0.2% along with insecticide
Dimethoate 1.5g/lit
• Spray of 1% starch solution makes flakes of the fungus and
due to small wind falls of from the plant.
12. 5. Red rust
• Cephaleuros versicolor.
• The algal disease and it has been observed in India and else
where. It is one of the minor disease of importance.
• Reduction in photosynthetic activity and defoliation as a result
of algal attack lower vitality of the host plant.
13. Symptoms
• The disease is characterized by initial
green coloured, circular patches with
marginal serrations.
• The upper surfaces of the spot consist of
numerous, unbranched filaments, which
project through cuticle.
• As and when disease advances the
organism turns red rusty spots on the
leaves and young twig.
• Spores mature, fall off and leave cream
to white velvet texture on the surface of
leaf.
14. Epidemiology
• The disease is more common on close plantation.
• The zoospores cause initial infection.
• High moist condition favours development of fruiting bodies
of the algae.
Management:
• it is controlled by spraying with Bordeaux mixture 1% or
Copper Oxychloride 0.3% or lime sulphur 0.2%.