عرض الجزء الثاني امراض نبات د. مهدي باحسن.pptx

The effect of the Environment
on the detection and
Emergence of plant diseases
‫أمراض‬ ‫وظهور‬ ‫تكشف‬ ‫على‬ ‫البيئة‬ ‫تأثير‬
‫النباتات‬
‫المعدية‬
‫أعداد‬
‫د‬
.
‫مهدي‬
‫سعيد‬
‫باحسن‬
‫كلية‬
‫العلوم‬ - ‫قسم‬
‫االحياء‬
‫الثاني‬ ‫الجزء‬
–
‫النظري‬

Environment is the factors surrounding plants from
heat - Humidity - light - soil ...., and these factors
may help the spread of the disease and the incidence
and severity of the disease if it is suitable for the
growth and reproduction of pathogens or work to
increase the resistance to diseases and the disease
does not occur if it is suitable for the growth of host
plants .Plant disease is only an interaction between
the three pillars of the disease triangle
(host plant - pathogen - environmental conditions).

 Disease Triangle ‫مرض‬
‫المثلث‬
The disease
TIME
 Pathogen host

1- Temperature ‫الحرارة‬
The pathogen needs an optimal temperature in its growth and
reproduction, and a drop or rise above this degree leads to little
growth or stop the infection or not to occur,
For example: -
Late blight on potatoes and Tomatoes caused by the fungus
Phytophthora infestanse need a low Temperature to grow, spread
and injury, while other diseases at high Temperatures. The life
cycle of Puccinia graminis tritici, caused by black stem rust, takes
5-6 days at the optimum Temperature (23Cº) while the disease
cycle takes 22 days at 5C°.

Each pathogen has an optimum degree
of humidity, which increases its growth
and reproduction.
High humidity affects the induction of
fungal spores on germination, and
ciliary spores and bacterial cells need
aqueous medium on the surface of the
leaf to move in, and some causes low
humidity, such as powdery mildew.‫البياض‬
‫الدقيقي‬
2- Humidity ‫الرطوبة‬

3- Wind ‫الرياح‬
The wind plays a role in the transfer of pathogens
from one place to another as they occur friction
between the plant parts, which causes damage to
their surfaces are scratches and wounds and
facilitates the process of injury due to the entry of
pathogens from those wounds.

4- Light ‫الضوء‬
Light is less effective than heat and humidity on
plant pathogens, but the effect of light is evident on
bacteremia in some fungi, such as Alternaria spp,
and low light encourages severe disease .Such as
Tomato infection with Cladosprium fulvm. Poor
lighting also helps with viruses.

5- Soil acidity (pH) ‫حموضة‬
‫التربة‬
The pH of the soil affects the density and presence
of pathogens and the appearance of diseases.
For example, the maceous root disease in
Plasmodiophora brassica caused by the fungus in
acidic lands at pH between 5.7 - 6.2 and stops
completely at pH 7.8, while the normal scabies
disease in the potato caused by Streptomyces
scabies in alkaline lands.

6- Ground water level ‫مستوى‬
‫الماء‬
‫األراضي‬
High water level of land directly affects the spread
of diseases, causes the growth of roots in the
surface area of the soil and weakens them.
Excess irrigation leads to high soil moisture and
therefore the spread of plant diseases, such as in the
pathogenic rust disease caused by Paccinia pruni-
spinosae, as well as bacteria and nematodes.
scabies in alkaline lands.

7- Nutrients ‫المغذيات‬
Plants that have a balanced nutrition (soil salts) are more
resistant to disease, while fluctuation in the amount of
nutrients in the soil leads to weak growth of plants and
helps to get sick. For example:- increased Nitrogen
fertilization encourages vegetative growth of the plant and
become tissue juicy and thin The root thus becomes more
susceptible to diseases such as rust in wheat and fire blight
in pears and apples, while the addition of potassium
reduced the incidence of wilt of cotton and fusarium
Tomatoes.

Survival by Means of Specialized Resting
- Ischia Spores or conidia spores emerging from them to preserve the fungus
that causes the wrinkle of peach leaves Taphrina deformans during the winter.
- As well Conidia spores of the Alternaria solani fungus that cause early
symposium disease in Potatoes and Tomatoes remain alive for 18 months in dry
leaves.
- Some fungi can also survive in inappropriate seasons on static stone
objects such as those produced by the fungus that causes Sclerotinia sclerotiorum,
which remains for several years in dry weather.
- Mealy white fungi and other ischemic fungi survive in perithecia.
Survival of plant pathogens
‫قدرة‬
‫المسببات‬
‫البقاء‬
‫حية‬
‫أجسام‬
‫متخصصة‬ ‫ساكنة‬

2- Survival as saprophytes
The ability to live in a restored state helps some plant
pathogens to survive in the absence of plants.
- Most fungi and bacteria causing plant diseases can
live restored in the soil, such as Rhizoctonia solani
and Pythium spp fungi that cause seedling fall and
root rot.
Survival of plant pathogens
‫مترممة‬

Survival in Vital Association with living plants
Ustilago tritici fungus that causes bulk smut in wheat enters
through flower seasons and infects the seeds and remains alive as
a mesilium dwelling next to the embryo and the seeds remain
alive.
Also, potato mosaic virus is carried through tubers, as well as
vegetative reproductive organs used in agriculture, transmit plant
viruses from one season to another growth season.
‫النباتات‬ ‫مع‬ ‫باالرتباط‬

Survival in Association with Nematodes and Fungi
There are at least 6 plant viruses, including wheat
mosaic, foliar smoke, and cyclic stains in the smoke that
survive with nematodes or fungi in the soil
For example:- the smokescreen virus is associated with
Xiphinema americana nematode, and the smoke ulcer
virus is transmitted by the fungus Olipidium brassica.
‫النيماتودا‬ ‫بصحبة‬
‫والفطريات‬

Survival in Association with insects
Many insects carry infectious vaccine, and many important
pathogens survive between growing seasons outside or inside
insects, for example:-
- Bacteria causing wilt of cucumber crosses the winter
period by a planned cucumber beetle.
- There are a number of plant viruses multiply within the
insect hopper vector and remain alive for the duration of
winter within the bodies of these insects.
- Mycoplasma and fungi that cause forest tree diseases
transmit mostly insects.
‫الحشرات‬ ‫بمصاحبة‬

A) Pre-penetration
This is the stage when the vaccine reaches the
surface of the host plant where the spores or
infection units stick and are fixed on the host
surface. In this stage, some changes in the pathogen
cause such as germination of fungal spores and
seeds of fine plants and nematode eggs.
‫والطفيل‬ ‫العائل‬ ‫بين‬ ‫الفسيولوجية‬ ‫العالقة‬
‫االختراق‬ ‫قبل‬ ‫ما‬

B) Penetration phase
This stage involves the entry of the pathogen
through different ports into the host tissue to
obtain food.
‫االختراق‬

C) Post-penetration
After successful penetration, the parasitization process
begins immediately, whereby the parasite obtains the
necessary food for growth and reproduction, and then
begins to show the host plant pathological symptoms
where the pathogen maintains a close relationship with
the host's tissues.
Nurses differ in terms of how the tissue of the host is included:-
‫بعد‬ ‫ما‬
‫االختراق‬

1- Direct Penetration
Many types of fungi and nematodes can penetrate directly into
the host's surface by mechanical pressure on the surface of the
plant through the enemy Haifa or adhesion member in the
fungus or by spear in the nematode and with the help of
enzymatic activity of the pathogen soften the cell wall materials
to facilitate the process of penetration.
The Rhizoctonia fungus enters the plant tissue by infecting the
infection and the Erysiphe fungus penetrates the leaf surface
directly by forming an adhesion member on the surface and the
thread of infection penetrates the plant.
‫مباشر‬

2- In Direct Penetration
-
Some pathogens enter the plant tissue through wounds, scratches and cracks
due to several different factors such as wind, cold, lightning, temperature
fluctuations, biting insects, animals and various agricultural processes.
The main pathogens that enter through wounds Penecillium fungus and
bacteria Corynbacterium.
-
Many pathogens enter through natural openings in the plant
(stomata, lenses, nectar glands, water stomata)
‫مباشر‬ ‫غير‬

(A) Stomata
Through the stomata enter Puccinia graminis tritici,
which causes black stem rust in wheat, where it grows
the spores made up of a germination tube and grows on
the surface until it reaches the stoma.
(B) Lenses
In this way, Cynchytrium endobioticum, which causes the
disease of black warts, Enters the potato where the
spores grows and a germination tube penetrates the
plant through the lentils on the stem of the potato
tubers.
‫العديسات‬
‫الثغور‬

(C) Water stomata
Xanthomonas compestris, which causes black mold
disease, enters the crusades through the water stomata.
The bacteria accumulate in the leaching water outside
the water stomata.
(D) Nectar glands
One of the most important pathogens that can enter
through the nectar glands in the flowers are the blight
bacteria on the apples Erwinia amylovora.
‫المائية‬ ‫الثغور‬
‫الرحيقية‬ ‫الغدد‬

‫للمرض‬ ‫المقاومة‬ ‫النباتات‬
1- Mechanical resistance
I. Defensive structures already present in the plant
before injury prevent injur ‫اإلصابة‬ ‫حدوث‬ ‫تمنع‬ ‫أصال‬ ‫موجودة‬ ‫دفاعية‬ ‫تراكيب‬
such as :-
- Thickness of the skin layer due to the presence of a
quantity of wax and layer of Qiotikal on the skin.
- Daily timing to open the gap and install the gap.
- Early and delay in maturity.
‫الميكانيكية‬ ‫المقاومة‬

I. ‫تراكيب‬
‫بالممر‬ ‫لإلصابة‬ ‫استجابة‬ ‫تتكون‬ ‫دفاعية‬
‫ض‬
II. Defensive structures formed in response to
infection with the pathogen ‫بالممرض‬ ‫لإلصابة‬ ‫استجابة‬ ‫تتكون‬ ‫دفاعية‬ ‫تراكيب‬
such as:-
1) The formation of a cork barrier is made up of several layers behind the
area of injury to prevent the advancement of the pathogen.
2) Deposition of the telosate in the vessels to impede transmission and progress
of the pathogen.
3) Deposition of lignin and soprin during short periods of wound incidence.
4) The formation of a separation layer between two layers of cells surrounds
the area of injury and thus separates the area from the rest of the paper and
fall.
5) Hypersensitivity reaction Once the pathogen penetrates the cell wall, the
nucleus moves toward the pathogen and breaks down and forms in the
cytoplasm.

2- Biochemical resistance
A- Existing materials originally ‫ا‬‫ل‬‫أص‬ ‫موجودة‬ ‫مواد‬
Before infection, such as red dye in red onion varieties resistant to
black onion disease, where inhibited germination of fungus germs.
B- Material Updated After injury ‫مواد‬
‫بعد‬ ‫مستحدثة‬
‫اإلصابة‬
Such as the accumulation of phenolic substances and the increased
activity of the oxidizing enzymes of phenols and their conversion to
the toxic quinones of the pathogen.
Or the production of phytoaloxins, which are toxic substances
produced in the plant in quantities can be estimated and formed only
after the plants are alerted by different types of pathogens or
mechanical or chemical damage and restrict phytoaloxins pathogen
and prevent infection.
‫البيوكيميائية‬ ‫المقاومة‬

The genetic relationship between the host and
the pathogen
1- Immune plants
It does not show symptoms of infection, and
there is no plant immune to all pathogens
and be immune to a parasite and sensitive to
another parasite.
2- Resistance plants
They are infected to a small degree that does not
affect the crop, because the plant has mechanical and
biochemical resistance factors that contribute to
counteracting, inhibiting or preventing the
advancement of the pathogen within plant tissues.
2- Vulnerable plants
(Sensitive)
It is the inability of the plant to resist the effect of the
pathogen, and the crop is economically affected by the
death of the plant in whole or in part and entails loss
in production.
‫الممرض‬ ‫والكائن‬ ‫العائل‬ ‫بين‬ ‫الوراثية‬ ‫العالقة‬
‫المنيعة‬ ‫النباتات‬
The pathogenicity of the host and the parasite in the Environment is determined
by genetic factors.
‫المنيعة‬ ‫نباتات‬
‫نباتات‬
‫المقاومة‬
‫نباتات‬
‫حساسة‬

a. Single gene resistance
It means that only one gene in a plant is
responsible for superior resistance in a
plant.
b. Low gene resistance
It means that two or three genes in a plant
are responsible for plant resistance.
c. Multi-gene resistance
It means the presence of multiple genes
responsible for resistance in the plant.
1. Resistance depending on the number of genes
‫النباتات‬ ‫تقاوم‬ ‫كيف‬
‫الجينات‬ ‫عدد‬ ‫حسب‬
‫الجين‬ ‫وحيدة‬
‫الجينات‬ ‫قليلة‬
‫الجينات‬ ‫متعددة‬

a. Vertical resistance
Where we find the resistance of
the host class high for some
physiological strains of the
pathogen and low for other strains
b. Horizontal resistance
It is the host resistance to all
physiological strains of the known
pathogen, knowing that there is
always the possibility of the
emergence of new strains of the
pathogen capable of overcoming
this resistance.
2. Specific and general resistance ‫مقاومة‬
‫نوعية‬
‫والعامة‬
‫رأسي‬
‫ة‬
‫أفقية‬

In many cases, the plant is susceptible to disease at some stage of its
development and is resistant in others.
Some types of resistance appear only under certain environmental
conditions, usually conditions that are inappropriate for the growth
of the pathogen.
Field resistance is a term called resistance in the field and not in greenhouses,
and this resistance does not know its genetic and physiological foundations and
when analyzing the nature of this resistance found that the resistance enjoyed by
mature plant or environmental resistance.
3. Resistance depending on plant Age ‫حسب‬
‫النبات‬ ‫عمر‬
4. Environmental resistance ‫البيئة‬ ‫حسب‬
5. Field resistance ‫حقلية‬

Resistance that may not last but keep the life of the
commercial class, that is, until it is replaced by another.
It is the ability of the plant to tolerate the disease and continue to
grow and produce a good crop even with the emergence of plant
disease.
6. Sustainability Resistance ‫المداومة‬ ‫حسب‬
7. Endurance ‫التحمل‬ ‫حسب‬

‫قدرة‬
‫على‬ ‫الممرض‬
Mutation
These are sudden spontaneous changes in the
genetic makeup of the organism that are rare and
may appear in the form of
( Increase or decrease in the rate of growth
- The production of enzymes - The
production of toxic substances - Carrying
toxic substances ).
( ‫النمو‬ ‫معدل‬ ‫في‬ ‫نقصان‬ ‫أو‬ ‫زيادة‬
-
‫اإلنزيمات‬ ‫إنتاج‬
-
‫السامة‬ ‫المواد‬ ‫إنتاج‬
-
‫السامة‬ ‫المواد‬ ‫حمل‬ )
There are factors and materials causing mutations such as :-
( X-rays, Ultraviolet radiation(UV), Toxic substances ).
‫طفرة‬

‫قدرة‬
‫على‬ ‫الممرض‬
Hybridization
Hybridization leads to increased vitality
and increased ability to cause infection
and thus overcome the resistance genes in
the host.
‫التهجين‬

‫األوبئة‬ ‫علم‬ ‫أساسيات‬
Epidemiological
diseases
They occur suddenly and spread quickly and are very
stressful and cause significant losses on the crop and
appear occasionally and at irregular intervals.
Endemic diseases
These are diseases that spread within their area of
endemism in the region and are not sudden and have
a moderate to severe adverse effect on plants.
Emergency diseases
(Sporadic)
Diseases that are found in individual cases, are less
prevalent, have no effective effect on the crop and are
found in season without season.
Epidemiology:- It is the science that studies the sudden rapid spread of the
disease.
‫الطارئة‬
‫المستوطنة‬
‫الوبائية‬

1. The presence of many vulnerable families.
2. High degree of susceptibility in crop plant.
3. Increased pathogen density.
4. Strains (ferocity) of the pathogen are highly
capable of inducing the disease
5. Suitable environmental conditions.
6. Continued favorable environmental conditions
for a long period of time.
Conditions of Epidemic disease ‫الوباء‬ ‫شروط‬

* Know the weather conditions such as measuring
temperature, humidity, wind direction and light rays
* These measurements are taken within the field near
the surface of the plant and at different heights.
* Estimate the amount of infectious vaccine such as
measuring the number of germs in the atmosphere and
their altitudes.
‫أوبئة‬ ‫بحدوث‬ ‫التنبؤ‬
It is this information that can be collected to predict the occurrence of the disease

- Number of descending germs on the plant surface.
- Measuring the progression of the disease on the plant.
* Number of pimples *Area of pimples * Spots relative to area.
*
‫البثور‬ ‫عدد‬
*
‫البثور‬ ‫مساحة‬
*
‫الورقة‬ ‫مساحة‬ ‫إلى‬ ‫البقع‬ ‫نسبة‬
.
* Ability to save information for many years. * Accuracy of calculations.
* Quickly get results.
*
‫عديدة‬ ‫لسنوات‬ ‫المعلومات‬ ‫حفظ‬ ‫على‬ ‫القدرة‬
* .
‫الحسابات‬ ‫دقة‬
* .
‫النتائج‬ ‫على‬ ‫بسرعة‬ ‫الحصول‬
.
‫أوبئة‬ ‫بحدوث‬ ‫التنبؤ‬
Thus it can be estimated
Such as recording the germination of spores on the surface of leaves
This method is characterized by
‫تسجيل‬
‫الورقة‬ ‫سطح‬ ‫على‬ ‫الجراثيم‬ ‫إنبات‬

Estimating the spread of disease and estimating
losses
* Estimation of the prevalence of the disease
(incidence)
* and the degree of severity of infection on a single
plant.
Number of infected plants
Prevalence rate = −−−−−−−−−−−−−−−−−−−− x 100
Total number of plants
Estimation of the severity of the infection varies depending
on the type of the affected part, whether it is on Tubers or on
the stem or leaves.
In estimating disease losses, he likes :-
‫والخسائر‬ ‫المرض‬ ‫انتشار‬ ‫تقدير‬

Estimating the spread of disease and estimating
losses
Then the severity of the injury is
calculated by the equation
DS = The severity of the injury. ∑ = (Total ab)
a = Degree of scale. b = The number of plants that
took the same degree.
r = Number of degrees of scale. N = Total number of plants.
Knowing the incidence and severity of the infection, the severity of
the disease can be estimated on the crop.
Severity of disease = prevalence rate x severity of infection
‫المرض‬ ‫شدة‬
=
‫المرض‬ ‫انتشار‬ ‫معدل‬
x
‫اإلصابة‬ ‫شدة‬
In estimating disease losses, he likes :-
‫والخسائر‬ ‫المرض‬ ‫انتشار‬ ‫تقدير‬
∑ ab × 100
DS =
rN

Control of plant diseases
1-
Agricultural
quarantine
It is a laws and legislation issued by the
States that prevent the entry of plant
pathogens into free areas, and
agricultural quarantine are Two types:
International
agricultural
stone
Plants and means of propagation are
examined by specialists in border areas.
Internal
agricultural
stone
It is prohibited to move crops and plants
from one area to another within the
country.
‫دولي‬ ‫حجر‬
‫الزراعي‬ ‫الحجر‬
‫داخلي‬ ‫زراعي‬ ‫حجر‬
- Means to combat plant diseases

health certificate
It is issued by specialized certified and
accredited bodies stating that crops are
free from pests and diseases. It is stated
that plants were examined by the
quarantine officer and his name and
description
- Means to combat plant diseases
‫صحية‬ ‫شهادة‬

a. Production and cultivation of
resistant varieties.
b. Use of agricultural courses.
c. Improve plant growth conditions
d. Tissue culture.
e. Health procedures.
3- Agricultural roads ‫الطرق‬
‫الزراعية‬

some microbes in the environment to act against the
growth and activity of pathogens
* It is carried out by injecting the soil with
antibodies or used as a biocide sprayed on
the vegetative total.
One of the most important species used in biological
control :- * Bacillac ‫بكتيريا‬ * Trichoderma ‫فطر‬
* Agrobacterium radiobacter has also been used in
the fight against coronary tuberculosis caused by
Agrobacterium tumefaciens.
4- Dynamic methods ‫الحيوية‬ ‫الطرق‬

By using temperatures or heat treatment
of soil, seeds or plant assets used to breed
with hot water to kill the parasites they
carry, hot air can also be used.
Reducing or decreasing moisture and
controlling temperatures by cooling stores
increases resistance to post-harvest
diseases in stores.
5- Physical methods ‫فسيولوجية‬

1-Pesticides
(protective)
Systemic pesticides
6- Chemical methods
‫جهازية‬ ‫مبيدات‬
‫وقائية‬ ‫مبيدات‬
‫تستخدم‬
The pesticide is used for

- Spray on the green parts
- Treatment of seeds and reproduction parts before
planting with pesticides to kill the parasites inside and
prevent infection of soil pathogens.
- Treat soil before planting by vaporizing the soil with
pesticides to kill pathogens in the soil
- Treatment of wounds and pruning sites in trees with
appropriate material such as tar, wax or wound paste to
prevent the entry of pathogens.
6- Chemical methods
‫تستخدم‬

- Control post-harvest diseases where products are
immersed in chemical solutions immediately after
harvest.
- Disinfect stores to avoid injury to stored materials and
clean, wash and vaporize walls.
- Control insect vectors with insecticides to prevent the
transmission of diseases from infected plants to healthy
plants.
6- Chemical methods
‫تستخدم‬

Soil treatment
a. Soil insolation.
b. Following agricultural methods.
c. Soil treatment with pesticides.
d. Pollination of soil with antibodies.
‫التربة‬ ‫معاملة‬

Seed treatment
a. Seed cleansing.
b. Following agricultural methods.
c. Seed treatment by heat and
radiation.
‫معاملة‬
‫التقاوي‬

Plant treatment
a. Following agricultural methods.
b. Plant fertilization to improve plant growth.
c. Agricultural quarantine procedures.
d.Chemical treatment by spraying and fogging.
e.Use of antibodies.
‫معاملة‬
‫النبات‬

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