1. The document describes four main diseases that affect opium poppy: downy mildew caused by Peronospora arborescens, Alternaria leaf spot caused by Alternaria phragmospora, powdery mildew caused by Erysiphe polygoni, and mosaic caused by Poppy Mosaic virus. 2. It provides details on the symptoms, etiology, epidemiology, and management of each disease. Symptoms vary between diseases but include spots, blights, mildew growth, and mosaic patterns or stunting. 3. Management strategies for the diseases include removing infected plant debris, practicing crop rotation, using resistant varieties, and applying appropriate fungicides or insecticides depending

1. Siddu Lakshmi Prasanna
Course No.: PATH 2.7.1.
Course Title: Diseases of Fruit, Plantation, Medicinal
and Aromatic crops
By
Dr. Siddu Lakshmi Prasanna
Ph. D (Agri.)
Dept. of Plant Pathology

2. Opium

3. Sr. No. Disease Causal organism
1. Downy mildew Peronospora arborescens
2. Alternaria leaf spot Alternaria phragmospora
3. Powdery mildew Erysiphe polygoni
4. Mosaic Poppy Mosaic virus

4. Downy mildew:
Causal organism: Peronospora arborescens
The plants with infection have two kinds of symptoms viz., Topical and
systemic
In topical infection
• Lower portion is healthy and upper portion diseased.
• In the upper diseased portion of the plant, the leaves remain small,
chlorotic, curling downward at the edges and are closely placed.
• Affected tissues curled, thickened and became deformed and necrotic,
leading to premature drying of the leaves

5. In systemic infection
• The leaves near the tips and margins are covered with pale brown spots.
• The growth of severely infected plants was stunted and their leaves curled
and twist due to production of high amount of grey - violet fungal growth on
the lower side of the affected leaves.
• In the plants with leaf spot infection, the infected area becomes first chlorotic
and then necrotic.
• The leaf spots enlarge by coalescing with each other.
• Sporulation may occur on the underside of spotted area.
• The infection also spread to the stem, branches and even capsules.

6. • It caused hypertrophy and curvature of the stem and flower stalks
leading to premature drying and death of entire infected plants.
• The capsule, if formed, shrinks, gets wrinkled and dries gradually after
infection.
• Heavy sporulation occurs on peduncle, buds and capsules which is not
persistent.
• Brownish black structures develop in place of normal seeds.
• The infected plants die prematurely

10. A, Chlorotic lesions on leaves at
initial shooting stage.
B, Chlorotic lesions and initial
sporulation on the flower bud at
initial flowering stage.
C, Chlorotic lesions and initial
sporulation on the flower peduncle
at the flowering stage.
D, Green capsule formed on main
plant stem showing intense
sporulation and deformation of the
capsule stem.
E, Capsules with intense sporulation
and seeds of reduced size of a highly
susceptible genotype

11. ETIOLOGY
• Mycelia- The mycelium is hyaline, coenocytic and
intercellular.
• Sporangiophores are erect and very long. They are 7-
10 times dichotomously branched and the ultimate
branches are fine, curved, sharp, diverging almost at right
angles, pointed at the tip.
• At the tip bears a single round –oval sporangium
.Sporangia are hyaline or pale violet.
• Asexual spores – Barrel shape sporangia borne on
sporangiophore
• Sexual spore- Oospores borne in oogonium
• Oospores are round yellow, thick walled
surrounded by an irregularly thick and
reddish brown wall

12. Mode of survival
• Primary source of inoculum: Oospores survives on plant debris of infected
plants or in the soil for years. Dormant mycelium in crop residue can also
initiate infection. Mycelia fragments on capsule may serve as source of
infection
• Secondary source of inoculum: Zoospores spread through wind, water splash
• The fungus infects Argemone mexicona, A. platyceras, Meconosis sp. Papaver
dubium, P. argimone and P. rhoeas.
• The disease is carried from one season to another by means of thick walled
oospores. It is not seed borne.

13. EPIDEMIOLOGY:
• Temperature 22-24°C
• Relative humidity- 90-95%
• Intermittent rain fall
• Susceptible host.
• In India it is noticed during a middle of February, When the crop is fully grown.
• It is also noticed during November-February. It appears on seedling and such
affected seedlings are killed.
• Yield loss from 7-65%.

14. MANAGEMENT:
• All disease plant should be uprooted, collected and destroyed.
• Early sown (30th October) crop was less affected by downy mildew incidence.
• Spraying of protective fungicides such as mancozeb prior to the appearance
• Seed treatment with metalaxyl + four sprays of metalaxyl at 0.2% at 35, 55,
75 and 95 days after sowing.
• Opium poppy cv. ‘Rakshit’, Jawahar-540 are resistant.
• The poppy line Vo.141, JOP 539 and MOP 540 is found to be highly resistant
to the disease.

15. Alternaria leaf spot
Causal organism: Alternaria phragmospora
Symptoms
• The initial symptoms of the disease were formation of numerous small, dull
brown necrotic spots all over the leaves and peduncle.
• In later stages of infection the spots enlarged rapidly, coalesced and turned
to brown necrotic patches leading to production of typical blight symptoms.
• Sometimes, dark brown patches were surrounded with chlorotic halo.
• Severely infected peduncle of opium poppy also turned pink to brown.

17. Management:
• Removal and destruction of the plant debris from severely infected
fields
• Crop rotation
• Use of disease resistant cultivars.
• Spraying of mancozeb (0.25-0.3%) just after the first appearance of
the disease at an interval of 15 days.

18. Powdery mildew:
Causal organism: Erysiphe polygoni
Symptoms:
• The fungus attacks all the green plant parts at all stages of plant growth.
Powdery mildew is observed in the fields at or after flowering stage i.e. nearly
14-16 weeks after sowing.
• Late sown crop (after 15th November) develops heavy powdery mildew
disease.
• The base of the stem is attacked first where it appears as small, circular
patch consisting of radially arranged mycelium. This enlarges gradually and
sporulation occurs soon.

19. • The fungus produces white to grayish powdery patches on the affected
plant parts including fruits but young leaves are most susceptible and
develop small whitish patches both on upper as well as lower surface.
• These patches grow in size and coalesce to cover large areas on the leaf
lamina.
• Malformation and discoloration of the affected leaves are also common
symptom, resulting in distortion.
• Similarly, powdery patches are produced on the stem, tendril, flowers
and young fruit branches.

20. • Diseased vines appear wilted and the stem portion turns brown.
• The infected blossom and berries turn dark in colour, irregular in
shape and brittle.
• In advance stage of infection, berries may develop cracks and such
berries do not develop and ripe.

22. ETIOLOGY: Erysiphe polygoni
• Mycelia is septate, external thin mycelia, haustoria is sub epidermal, obligate parasite.
• Asexual spores are barrel shape conidia borne on oidiophore in chains asexual
fruiting body oidia.
• Sexual spores are ascospores inside the Ascus in the ascocarp Cleistothecium
MODE OF SPREAD AND SURVIVAL:
Primary source of inoculum :Ascospores, Dormant mycelia.
Secondary source of inoculum: oidia wind borne
• It survives as dormant mycelia and as Cleistothecia on the shoots and buds from season
to season. The disease spreads by the air- borne conidia.

23. EPIDEMIOLOGY:
• The disease occurs in severe from Oct- Nov in North India and Feb- June in
South India.
• Disease is favoured by warm sultry weather and retarded by sunshine.
• Warm winter temperature from 20 to 33.5°C has been found to be the cause for
epidemic in Hyderabad.
• Disease development is adversely affected by rain.

24. MANAGEMENT:
• The proper air circulation through the canopy and prevent excess shading
help in reducing the disease.
• Sanitation is also important in reducing the disease pressure during the
growing season.
• Crop sown before 15th October almost escape the disease.
• Only one spray of 0.5% wettable sulphur at the time of first appearance
of the disease in the field or when the crop has reached the age of 80 days
or when the maximum daily temperature has reached 27°C and above or
spraying of bayletan or Kerathane (0.05%).

25. Mosaic:
Causal organism: Poppy mosaic virus
• Symptoms were more pronounced during February and March.
• It causes stunting, vein banding and deformed capsule formation.
• The characteristic disease symptoms were mottling, mosaic, irregular
necrosis, distortion of capsule and puckering of leaves especially the terminal
ones.
• Infected plants produced abnormally smaller leaves than those of uninfected
healthy plants.
• In some instances floral organs were converted into malformed structures,
consequently, failed to produce normal types of capsules.

26. • The infection caused very low production of alkaloids.
• Infected plants eventually lost vigor and showed premature death
and drying.
• Sometimes the infected plants produced rosette due to the reduction
of terminal growth and shortened internodes

28. Mode of spread and survival
• Primary source of inoculum: Affected host plants, weed host (A. Mexicana)
& self sown crops.
• Secondary source of inoculum: Virus particle transmitted by aphid vector,
Myzus persicae.,
The virus is non persistent type.
Potyviridae, Potyvirus, +ssRNA, flexious rods

29. Epidemiology
• Summer season, High temperature, Susceptible host
• Improper management leads to development of this disease.
Management
• Initially spray Dimethoate 0.1% after 15 days and Imidacloprid
0.05 % at another 15 days and neemazol 0.5 % later.