Relative humidity, temperature, rainfall, and other weather-related factors are critical for forecasting outbreaks of leaf spot disease in bananas. A model can graphically depict the optimal temperature and humidity conditions from month to month that favor disease development. Maintaining proper spacing, controlling weeds and humidity levels in banana plantations, and applying fungicides appropriately are important for disease management and maximizing yields.

1. ..
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2. DISCUSSION OF IMPORTANTDISCUSSION OF IMPORTANT
FACTORS FOR FORECASTING ANDFACTORS FOR FORECASTING AND
CRITICAL WEATHER MODEL OF LEAFCRITICAL WEATHER MODEL OF LEAF
SPOT OF BANANASPOT OF BANANA

3. ObjectivesObjectives
 TO KNOW THE FACTORS RESPONSIBLE FOR
FORECASTING
 TO KNOW THECRITICAL WEATHER MODEL OF
LEAF SPOT OF BANANA

4. INTRODUCTION
 Black leaf streak, also known as Black Sigatoka, was
first recorded in 1964 from Fiji. This fungal disease of
banana has since spread to most of the banana
growing regions of the world and is regarded as one of
the most important constraints on banana production
worldwide. The disease is particularly important where
growers cultivate monocrops of banana and cannot
afford to use chemical fungicides for disease control.
Black leaf streak can cause extensive defoliation. Yields
are reduced, and fruit from affected plantations is
prone to premature and uneven ripening. Because
banana bunch weight is a function of the number of
healthy leaves at flowering, it is critical to manage the
crop and the disease so that an acceptable quantity
and quality of fruit is harvested

5. WHAT IS FORECASTING?WHAT IS FORECASTING?
 Giving information in advance about the
epidemic of a disease and control measure.It is
the applied epidemiology.
 According to the Miller and O’Brien (1952)
–“Forecasting involves all the activities in
ascertaining and notifying the growers of a
community that ----
 conditions are sufficiently favourable for certain
disease
 applicatiom of control measures will results in
economic gain
 the amount of disease is enough to justify the
cost of expenditure

6. CAUSAL ORGANISM OF LEAF
SPOT OF BANANA
Mycosphaerella fijiensis
Cercospora musae

7. DISEASE SYMPTOMS
 The first symptom of LEAF SPOT OF BANANA is minute, chlorotic flecks
that appear on the undersurface of the third or fourth fully expanded leaf. The
flecks develop into narrow (1-2 X 10-20 mm) rusty brown streaks and often
have truncated ends and sides that are sharply limited by the leaf veins.
During early stages, the streaks are visible only from the lower surfaces.
 On some cultivars, and on very young plants (suckers) the streaks are less
defined and have diffuse margins
 The color of the lesions or streaks intensifies to dark red, brown, or black,
sometimes with a purple tinge, and they become visible on the upper surfaces
 The streaks enlarge, becoming fusiform or elliptical, and darken to give the
characteristic black streaking of the leaves. Conspicuous yellowing of
adjacent leaf tissue may also occur.
 The lesions dry to light gray with definite dark brown or black borders and
often have narrow, yellow transition zones between the borders and the green
leaf tissue.
 When disease severity is very high, large areas of the leaf may become
blackened and water-soaked. As with yellow Sigatoka, the spots on juvenile
leaves are oval or rounded and are often surrounded by a conspicuous yellow
margin.
 In extreme cases, all leaves can be destroyed before the bunch is mature, and
the bunch may fall from the plant.

8. SYMPTOMS

9. LIFE CYCLE

10. FACTORS RESPONSIBLE FORFACTORS RESPONSIBLE FOR
FORECASTINGFORECASTING
HUMIDITY
TEMPERATURE
HUMIDITY
RAINFALL
WIND
INOCULUM
SOIL
SOIL PH

11. CRITICAL WEATHER FOR LEAF
SPOT OF BANANA
RELATIVE HUMIDITY 80-90%
TEMPERATURE 10-16 DEGREE
CENTRIGRADE
CLOUDY WEATHER

12. MODEL FOR FORECASTING
A model is nothing but a sequential
hypothesis of what to do before
epidemic .It is the simple and easy
expression of forecasting information.
It can be expressed by graphically or
diagrammatically

13. A Critical weather model forA Critical weather model for
leaf spot of bananaleaf spot of banana ..
 .
February
January
Decemb
er
November
OctoberSeptember
August
July
June
May
April
March
Time of
forecasting

14. Control measure
Variety selection:
The variety agnishar,sagor kola,amrito sagor etc.
SPACING:
Single-row or double row planting systems allow
best fungicide coverage for bananas and have
superior air flow and reduced relative humidity
levels in the canopy.
Weed control:
Tall weeds (especially grasses) create high
humidity in the plant canopy, which favors
black leaf streak disease.

15. CHEMICAL CONTROL
 Febuconazole, tebuconazole are
reported to be the most
effective. As systemic
fungicides, the triazole
fungicides provide the longest
duration of disease mitigation
after application, but also pose
a risk for the development of
fungicide resistance if they are
over used.

16. CONCLUTION:CONCLUTION:
 BY FORECASTING MESSAGE OUR
FARMERS BECOME ALERT
ABOUT THE DISEASE AND TAKE
APPROPRIATE MEASURES TO
AVOID THAT DISEASE .THUS
HIGH YIELD IS ACCEPTED.SO
IT IS VERY LMPORTANT IN
AGRICULTURE.