Annexure VI

Plant Pathology
• Identification of diseases in different crops in host farmer’s field or any fields in village.
• Methods of taking observations in field crops/vegetables/fruit/crops regarding
disease incidence.
• Recording of observations on agronomical/horticultural crops regarding disease incidence.
• Calculation of disease incidence in related crop.
• Suggestion of control measures to the farmers and get the knowledge regarding
different Indigenous Technical Knowledge (ITKs) used by the farmers to control the
disease.
• Collection of twenty disease sample for preparation of disease herbarium at the time
of final report submission.

Method of taking observations in the field

• Enter into the field of the farmer and divide the field in five blocks.
• From each block select randomly five plants per meter row length for observation
from each block and have the sample of 25 plants/ field.
• Find out any abnormalities in plant like wilting, deformation and a discoloration
of leaf/stem/fruit/pod is present or not.
• Make sure that it occurred due to disease or any nutritional deficiency or pest attack.
• Make sure that which type of disease is it and take the sample to lab, verify it.

A) Fungal Disease:
Put your, self
captured infected
Name of the Example Identifying
Sl No crop plant
Symptom s of crop characters
photographs
affected
White grey, brownish or
Mildew (Downy Cucurbits, purplish growth on the
1. mildew, powdery crucifer, maize, host
mildew) sunflower surface

Red, brown, yellow or

black colour rusty
symptom appears
2. Rust Maize,
on the leaf and stem
sunflower
The affected plant
converted to black dusty
spore mass. It infects
3. Smut Maize
leaf, stem
and roots.

White blister like

4. White blister Crucifer pustules
 Tissue become dead at
the point of infection
5. Necrotic and generally
Leaf
symptom/spot surrounded by yellow
halo.

The stripe appear as

elongated line and
6. Streak or stripe Leaf and stem initially yellow in colour
later turn brown

Sudden death of leaves,

twig occurs and dead
7. Leaf, blooms
Blight organ changed to
and twigs
brown or black

Near the soil line the

stem affected with
8. Damping off Seedling rotten symptoms and
generally finally whole shoot
affected system
collapse
The affected tissue die
decomposed to a
9. Fruit, stem and
Rot great extent and turn
root
brown

Ulcer like lesion on

10. Anthracnose Fruit, pod and fruits and pods
stem

A flaccid or drooping
condition of leaves,
shoots or other parts is
Whole shoot usually due to a diseased
system, found vascular system which
11.
Wilt in Solanaceous ultimately resulted with
plants mortality of the
plant

A symptoms resulting
from the dying of twigs
or branches from the tip
12. Twigs or
Die-back towards the base.
branches
B) Bacterial disease: Bacterial disease can easily identify (those who are not showing any
symptoms specifically bacterial wilt) in the field as well as lab condition through Ooze test.
Ooze test – In this technique, stem portion of suspected plant samples cuts obliquely by a fine knife.
Then the cutted stem placed into a test tube (takes half of its volume with sterile distilled
water/normal water) and observed very closely. If small droplet of Ooze or viscous fluidal material
comes out from the cutted stem to the water, then we can say plant sample is infected with bacterial
disease. This is one types of rapid confirmatory test without lab trial.

C) Viral disease: Yellowing, curling of leaf, stunting of plant etc.

D) Phytoplasma disease: Little leaf of brinjal, Sesamum phyllody

• Methods of observation will slightly change from crop to crop. However, to get the
correct information enquire from your subject teacher (Pathologist) for recording
observations.

Schedule on monitoring the crops for disease occurrences and seeking their remedies
Name of the Students……….………………………………..Date……..............................
To monitor the crops for disease occurrence, each student should pay constant visit to the cropped area
and look for any unnatural growth and occurrence. Take samples to Department of Agricultural
Entomology, Plant Pathology and Physiology to identify the maladies if noticed or may be with the
teacher Get the remedies and make record.

Exercise
• Document the problems that you have identified and the remedies given by the experts
below in the table.
• Make regular record of observation during the entire course of time and draw conclusion.
Table 1 Schedule of monitoring the crops for disease occurrences and seeking remedies

Crop Disease Stage with date of Remedy given by

observation experts
Rice
Maize
Sorghum
Soybean
Groundnut
Sesamum
Vegetable -1
Vegetable -2
Vegetable -3
Any other crop

Conclusion:
I. Crop Disease Status and Damage in the Field of Host Farmers.
Name of Students :

Name of Village :

Host Farmer :

Name of the Crop :

Variety : Area:

Date of Sowing :

Stage of the Crop :

Objectives:

• To know the status of disease incidence on the cultivated crop.

• Students will be able to correlate the present disease incidence status with the ETL levels
of the disease incidence.
• On the basis of observation and available ETL level, the control measures to be adopted
by the farmer, it should be suggested by the student to the host farmer.

Table 2 Record of disease occurrence per meter row length for foliar disease
Total no. of leaves No. of leaves affected Percentage of
Block Plant present
Top Middle Lower disease incidence

1 1
2
3
4
5
2 1
2
3
4
5
Similarly, record of observations should be prepared to other types of disease.
Conclusions:
 Disease incidence:
The formulae used for determining the disease and pest incidence are:
Disease Incidence % =
No. of affected leaf/plant/tiller/pod x 100
Total No. of leaf/plant/pod assessed

If the percentage of disease incidence is above 50% i.e. near equal to Economic threshold level (ETL)
then control measure is recommended to farmer.
Total no. of leaf affected/hill or plant x 100
Seasonal Incidence % = Total no. of leaf present/hill or plant
 II. Crop disease status and damage in the fields of host farmers
Table 3 Record of disease occurrence in 25 square meter crop area (consider only those
much plants present under this area) of fruit and vegetable crop plants

Block Observation Fruit Disease A [Name] Vegetable disease B [Name]

Total Damage Per cent Total Damage Per cent
plants Damage plants Damage
1 1
2
3
4
5
Total
Average
2 1
2
3
4
5
Total
Average

Table 4 Record of disease occurrence of cereal crop like Rice [Fix the crop area 25 square meter]

Block Observation/Plants Total no. of tiller Total no. of affected Per cent Disease
present per hill tiller per hill incidence
1 1
2
3
4
5
2 1
2
3
4
5
1
2
3
3
4
5
Per cent Disease Incidence =

50
III. Control measures suggested to host farmers on the basis of disease damage.
1. Name of students :
2. Name of farmer :
3. Name of Crop/Variety :
4. Date of Sowing :

Table 5 Control measures suggested to host farmers on the basis of disease

incidence/ damage
Control measures Suggested control measures Adapted/not adopted by the
farmers along with the
Reasons
Cultural control
Physical control
Chemical
Biological
IDM

Information on IDM to be collected in the form of Questionnaire from the host farmer
Name of Students :

Name of the Farmer :

Name of Crop/variety :

Date of Sowing :

1. What is IDM ?
2. Do you know the components of IDM?
3. Which fungicides/bactericide is purchased by farmer?
4. Who suggested them to use in the crop?
5. Source of purchase of fungicides/bactericide?
6. How you decide the quantity of fungicides/bactericide to be purchased?
7. How you prepare the solution?
8. Dou you use measuring cylinder, weighing balance for correct measurement of pesticide?
9. How you spray the fungicides/bactericides?
10. Whether the pesticide is applied alone or in combination?
11. Whether you know the dose of fungicides/bactericide, do you calculate the dose of
fungicides/bactericide?
12. Time and dose of application of fungicides/bactericide?
13. Whether pesticides are applied as preventive or curative measures?
14. Do you know the precautionary measures to avoid poisoning?
15. Do you follow other methods of disease control?
16. Are the RAEO, extension workers/KVK's are guiding you in disease management?
17. Are the RAEO/Scientists pay visit your village/fields?
18. Do they advise IDM tactics for disease management?
19. Do you follow the advice given on TV/Radio in krishi Darshan regarding IDM?
20. Do you feel any difficulties while performing disease management in the field?

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Seasonal disease incidence (On two agronomical and one horticultural Crop)
Name of Students :

Name of the Farmer :

Name of Crop/variety :

Date of Sowing :

Table 6 Seasonal disease incidence (on two agronomical and horticultural crops)
Date of Name Damaging Plant Status of the Control Biocontrol
sowing of stage of Parts disease (Percent measures agent, if
Diseas Disease affected damage) undertaken anything they
e Low Medium High have
<10 10-30 % >30% applied/you
% suggested

Signature of Students Signature of Teacher

52
Preparation of Plant Disease herbarium

Plant disease herbarium can prepared by using the following steps -

Herbarium sheet measurement – Please make sure that size of the herbarium sheet is 42 cm (length) and
29 cm (width). For the preparation of herbarium sheet you can easily prepare the same by buying white
thick art paper or chart paper and by cutting it into aforesaid mentioned size.

1. Collection of diseases sample

In READY programme collection of plant disease sample for herbarium preparation is an important task. At
least 15-20 diseases sample should be collected. Plant disease sample collection is done by keeping the
following points in mind –
(i) Plant sample should be at least 6-8 cm in length.
(ii) Disease plant part should be water free.
(iii) Disease sample should be fresh and leaves will be in normal state means not fully died or decayed or
plant parts rolled.

2. Pressing and drying

Collected plant samples were kept in the old newspaper, magazines or books and put a heavy weight onto it.
But before putting heavy weight make sure that all the leaves of the plant samples will expand/stretched welly
under the paper.

3. Maintaining of the samples

For every 15 days interval change the pressed paper, because if moisture remains in your news paper, huge
number of microbial association can damage your plant samples totally. For avoiding of any kinds of microbial
or insect-pest attack in your plant sample 45% formaldehyde solution can apply. By an absorbent cotton very
little amount of formalin soaked and make the surface clean of your herbarium sample.

4. Sticking with herbarium sheet

Always try to stick your dry preserved samples by liquid gum (like fivocol). Try to avoid sticking with
cellotapes. As because any kind of cellotapes opens after a certain time and makes the herbarium sheets
appearance worst.

5. Filling of herbarium sheet token

Herbarium token should attach at the right side corner (down) of your herbarium sheet. Properly fulfills all the
information mentioned under the token. Sample of herbarium token is shown below. Mention the field record
number by cutting it from field record data sheet and paste the same on ‘field record no’ position on the
herbarium token.

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 DISEASE REPORT
Herbarium Sheet No :
FIELD RECORD NO : DATE OF COLLECTION :

NAME OF THE HOST :

NAME OF THE DISEASE :

NAME OF THE PATHOGEN :

GEOGRAPHICAL LOCATION :

COLLECTED BY :

IDENTIFIED BY :

IDENTIFYING CHARACTERS / SYMPTOMS :

NAME OF THE DEPOSITOR :

Field Report

Whenever you will go for collection of the herbarium samples every time you will borrow the field report. Make
a 30-50 pages field report (as par your requirement) with the sample field record data sheet (shown below).
Properly fill all the disease data description mention under the field report. Cut the righ side corner field report
no and paste the same on the herbarium token. This field record needs to submit along with the herbarium sheets.

Fresh Sample Photographs (Field condition symptomatological photography): Whenever you will collect
the herbarium samples, must be captured fresh sample photographs at the field condition. More specifically
symptomatological photograph in field condition should attach along with each and every disease description in
the field report. This looks like a book pattern where in left side fresh sample photographs paste on a A4 size
paper and on the right side field report data sheet present.

54
 FIELD REPORT FR -1
Herbarium Sheet No :

NAME OF THE HOST : Field

Record
NAME OF THE DISEASE :
(FR) No -
NAME OF THE PATHOGEN : 1
GEOGRAPHICAL LOCATION / ALTITUDE :

Irrigation -

Properly irrigated Moderately irrigated Poorly irrigated

WEEDING

Done properly Not properly (If not properly, then name of the
weeds/secondary hosts present)

EPIDEMIOLOGICAL PERSPECTIVE:

Temperature (°C) Humidity (%) Rainfall (mm) Soil type Soil pH

APPLICATION OF AGROCHEMICALS (Pre-treatment and post treatment) with doses –

Fertilizer Biocontrol agent Botanicals Fungicides Pesticides

COLLECTED BY :-

IDENTIFIED BY :-

IDENTIFYING CHARACTERS / SYMPTOMS :-

NAME OF THE DEPOSITOR :-