This document provides an overview of rice blast disease caused by the fungus Magnaporthe grisea. It discusses the scientific classification of the fungus, symptoms of rice blast including lesions on leaves, collars, necks and panicles. The disease cycle is described where spores produced on infected tissues spread to nearby healthy leaves. Rice blast occurs more frequently in Bangladesh in the month of October when temperatures and moisture are high. The document outlines control strategies such as resistant crop varieties, cultural practices and chemical/biological controls to prevent rice blast from destroying rice fields.

1. Welcome

2. Topic of the presentation
Draw a disease cycle of
BLAST OF RICE

3. The presentation will be run by
Md. Tarik Aziz
Reg. No: AGRW201400002
The questionnaire session will be done by
Name Reg. No
Mahabuba Khanom Munni AGRW201400005
Md. Hanif Hossain AGRW201400006
Shahnaz Parbhin Ruby AGRW201400008
Md. Tohorul Islam AGRW2014000011

4. What is rice blast?
Magnaporthe grisea, is a plant-pathogenic fungus that causes a serious disease
affecting rice.
It is also known as:
Rice blast fungus
Rice rotten neck
Rice seedling blight
Blast of rice
Oval leaf spot of graminea
Pitting disease
Ryegrass blast

5. Scientific classification of Rice blast
• Kingdom: Fungi
• Phylum: Ascomycota
• Class: Sordariomycetes
• Orde: Magnaporthales
• Family: Magnaporthaceae
• Genus: Magnaporthe
• Species: M. grisea

6. Review of the literature
• Host: M. grisea is an ascomycete fungus. It is an extremely effective
plant pathogen as it can reproduce both sexually and asexually to
produce specialized infectious structures known as appressoria that
infect aerial tissues and hyphae that can infect root tissues.
• Symptoms: Initial symptoms are white to gray-green lesions or spots
with darker borders produced on all parts of the shoot. Symptoms are
observed on all above-ground parts of the plant. Lesions can be seen
on the leaf collar, culm, culm nodes, and panicle neck node. Inter-nodal
infection of the culm occurs in a banded pattern. Nodal infection
causes the culm to break at the infected node (rotten neck).

7. Methods and materials
We have collected all thee information from secondary source.
Our materials as secondary source:
1. Different websites
2. Library books.
3. Different journals.

8. Overview
• There are some sign and symptoms of rice blast disease. Those sign and
symptoms will be discussed under overview.

9. Overview (Continued…..)
1. Rice leaves: The symptoms on leaves
may vary according to the
environmental conditions, the age of
the plant, and the levels of resistance
of the host cultivars. On susceptible
cultivars, lesions may initially appear
gray-green and water-soaked with a
darker green border and they expand
rapidly to several centimeters in length.

10. Overview (Continued…..)
2. Rice collar: Collar infections can
kill the entire leaf and may extend
a few millimeters into and around
the sheath. The fungus may
produce spores on these lesions.

11. Overview (Continued…..)
3. Rice necks: Necks are often infected at
the node by the rice blast fungus and
infection leads to a condition called rotten
neck or neck blast.
4. Rice panicle: Lesions can be found on
the panicle branches, spikes, and spikelets.
The lesions are often gray brown
discolorations of the branches of the
panicle, and, over time, the branches may
break at the lesion.
:

12. Overview (Continued…..)
5. Rice seeds: The fungus has
often been isolated from the
pedicels of the seeds. Seeds are
not produced when pedicels
become infected, a condition
called blanking. Symptoms of rice
blast on seeds themselves consist
of brown spots, blotches

13. Disease cycle of rice blast
• Generally, rice blast is favored by moderate temperatures (24oC) and periods of
high moisture that are 12 hours or longer.
• Spores produced as the primary inoculum on the overwintering tissues produce
the initial infections on young seedlings when the spores that are deposited on
leaves, germinate and invade leaf tissues.
• Lesions on the young seedlings appear within a few days after infection. These
secondary lesions produce more spores and these spores are readily wind
disseminated to nearby healthy leaf tissues. The secondary cycles can be
repeated many times during the growing season, with the potential for very high
amounts of disease within the crop
• Generally, the leaf phase of the disease is most severe when daily temperatures
are moderate, and when rice is over-fertilized, or if it is being grown in flood
waters below the recommended depths.

16. Rice blast in Bangladesh
• Frequency of rice blast in different month in Bangladesh:

17. Resistant cultivars of Rice blast
• On the basis of disease intensity, three were highly resistant, 12 resistant, 16
were moderately resistant and 1 was moderately susceptible at T. aman season
• At boro season 3 lines were found to be highly resistant, 8 resistant, 17
moderately resistant and 4 were moderately susceptible

18. Different control strategies for Rice blast
• Prevention and control.
• Resistant Crop Cultivars.
• Cultural Practices.
• Chemical Control.
• Biological Control.

19. Conclusion
Rice is staple food for us. So we will be obviously affected if any type of disease
destroy any whole rice field. We can clearly understand that by observing data
which is included in this assignment.
As blast disease found in that time when moisture is high, we need to be careful
about this when the temperature and moisture is high. From the statistical data,
we can see that the attack of rice blast is higher in October month. So we need
to very much careful about this in October.
If we won’t careful and won’t try to prevent and control this disease, our whole
country will be sufferer for the drastic attack of blast disease of rice.

20. Thanks
To
All