Your SlideShare is downloading. ×
0
MIC 319
FUNDAMENTALS OF
AGRICULTURAL
MICROBIOLOGY

CHAPTER 2
CAUSES OF PLANT DISEASES
BY
SITI NORAZURA JAMAL
03 006/ 06 48...
OUTLINE

Abiotic
factors

nutrients, pesticide
exposure,
environment
pollution,
temperature,
moisture, & light.

Biotic
fa...
ABIOTIC
FACTORS
1) Nutritional
abnormalities


Often nutrient abnormalities show up as
discoloration of foliage



Common discoloration ...
Nutrient deficiencies


Plants require several
major (N,P,Ca,Mg) and
minor (iron,copper,Zn)
elements for normal
growth.

...
Mineral Toxicity


Presence of excessive
available amounts of
certain minerals in the
soil can lead to mineral
toxicity t...
2) Pesticide Exposure
Some pesticides , if improperly used can
cause serious damage to plants.
 However, the most common ...
The common
symptoms of
herbicide
exposure are
curling and
cupping
 This plant was
exposed to the
herbicide 2,4-D

3) Environmental
Pollutants
High level of fluoride in water or fluorine gas
in the air can cause symptoms like this.
 The...
Air pollution
 Certain chemicals such as O3, SO2 and NO2 are
released into the air from factories, power plants
and autom...


Ozone damage
on morning glory



Ozone damage or
marijuana leaves
4) Extreme Weather Conditions
Extreme of weather can also lead to plant injury.
Cold injury
 Low temperature, like frost ...
5) High/low soil moisture
Due to excessive watering poor drainage or
flooding may cause plants to turn yellow
and be stunt...
6) high/low intensity




High light intensity is usually not a problem but
low light conditions, especially for indoor ...
BIOTIC
FACTORS
1)Fungi
Largest pathogen group
 More than 8000
pathogenic species
 Vegetative growth
through production of
hyphae
 Repr...
Fungal Hyphae




Some examples of plant diseases
caused by fungi:
brown rot of cherries, peaches and apricots; apple scab.
powdery m...
Brown rot

powdery mildew

(Monilinia fructicola)

(Triticum sp.)
2) Bacteria
About 200 pathogenic species
 Can be seen with a light microscope
 Simple, unicellular
 Reproduce by binary...





Some of the commonly
encountered bacterial diseases
are:
crown gall of rose, grape, apple, cherry and
other orname...
Crown Gall

Fire Blight

(Agrobacterium tumefaciens )

(Erminia amylovora)
3) Viruses








Can only be seen
using an electron
microscope
Extremely simplenucleic acid with a
protein coat.
Rep...




Viruses can multiply only in a living host
cell and can often spread systemically
throughout the infected plant.
Vir...
Viruses cause mainly two types of
symptoms: mosaics and leaf curls.
 Some examples:






rose mosaic
potato leaf roll
Rose mosaic

(Rose Mosaic Virus) (RMV)

Potato leaf roll (Polerovirus)
4) Nematodes
Parasite worms
 Very complex compared to other pathogens
 Usually seen only with a light microscope
 Repro...






Most of the nematodes feed on the
underground parts of the plants (roots,
tubers, bulbs, etc.) causing lesions o...
Root knot nematodes

(Meloidogyne)

Stubby root nematode

(Trichodoridae)
5) Phytoplasmas






A prokaryotic organism that lacks a cell wall and
survive in the phloem of plant
The helical ph...




Some of the commonly
encountered phytoplasmas
diseases:
aster yellows phytoplasma on carrots,
tomatoes, onions and l...
Aster yellows
phytoplasma
Upcoming SlideShare
Loading in...5
×

causes of plant disease

2,003

Published on

Published in: Technology, Health & Medicine
0 Comments
3 Likes
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total Views
2,003
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
89
Comments
0
Likes
3
Embeds 0
No embeds

No notes for slide

Transcript of "causes of plant disease"

  1. 1. MIC 319 FUNDAMENTALS OF AGRICULTURAL MICROBIOLOGY CHAPTER 2 CAUSES OF PLANT DISEASES BY SITI NORAZURA JAMAL 03 006/ 06 483 2132 norazura6775@ns.uitm.edu.my
  2. 2. OUTLINE Abiotic factors nutrients, pesticide exposure, environment pollution, temperature, moisture, & light. Biotic factors fungi, bacteria, nematodes, parasitic plants & virus
  3. 3. ABIOTIC FACTORS
  4. 4. 1) Nutritional abnormalities  Often nutrient abnormalities show up as discoloration of foliage  Common discoloration symptoms include:  Yellowing Chlorosis  Two types    Nutrient deficiencies Mineral toxicity
  5. 5. Nutrient deficiencies  Plants require several major (N,P,Ca,Mg) and minor (iron,copper,Zn) elements for normal growth.  Deficiency or lack of any of these essential nutrients results in disease symptoms in the plant.  The symptoms in this photo occur due to a lack of molybdenum (minor plant nutrient)
  6. 6. Mineral Toxicity  Presence of excessive available amounts of certain minerals in the soil can lead to mineral toxicity to the plants.  The extent of injury depends on the mineral, its concentration & species of the plant.  The plant in this photo has received excess manganese, which has proved toxic and led to yellowing.
  7. 7. 2) Pesticide Exposure Some pesticides , if improperly used can cause serious damage to plants.  However, the most common type of chemical injury to plants is due to soil residue or spray drift of herbicides.  Examples of pesticide toxicity are:    2,4-D damage to beans and tomatoes Glyphose (Roundup) damage to fruit trees
  8. 8. The common symptoms of herbicide exposure are curling and cupping  This plant was exposed to the herbicide 2,4-D 
  9. 9. 3) Environmental Pollutants High level of fluoride in water or fluorine gas in the air can cause symptoms like this.  The damage is concentrated towards the margins of the leaf where fluorine tends to accumulate.  E.g. Air pollution 
  10. 10. Air pollution  Certain chemicals such as O3, SO2 and NO2 are released into the air from factories, power plants and automobile exhausts.  These chemicals can accumulate in the atmosphere insufficient concentration to cause damage to plants.  Ozone damage appears in the form of chlorosis, spots and bleaching of young leaves.   This common in certain regions of the country where there is a high ozone concentration in smog Some of the air pollutants responsible for acid rain cause damage to vegetation in certain regions.
  11. 11.  Ozone damage on morning glory  Ozone damage or marijuana leaves
  12. 12. 4) Extreme Weather Conditions Extreme of weather can also lead to plant injury. Cold injury  Low temperature, like frost or freeze can damage the exposed or sensitive organs (buds, flowers, young fruits) or may kill the entire plant.  As the new branch tips began to expand, a period of cold was severe enough to kill the growing tips. Heat injury  In this case the temperature was high enough and damage the plant tissue  When plants or plant parts are exposed to high temperature for prolonged periods, symptoms of scorching or scalding may develop. 
  13. 13. 5) High/low soil moisture Due to excessive watering poor drainage or flooding may cause plants to turn yellow and be stunted.  Potted indoor plants may show poor development or root rots.  At the other extreme, low moisture or drought conditions can lead to poor development, wilting and death of plants. 
  14. 14. 6) high/low intensity   High light intensity is usually not a problem but low light conditions, especially for indoor plants, lead to etiolation (tissue are yellowish) A normal and etioled shoot under sun and artificial lighting.
  15. 15. BIOTIC FACTORS
  16. 16. 1)Fungi Largest pathogen group  More than 8000 pathogenic species  Vegetative growth through production of hyphae  Reproductive via spores 
  17. 17. Fungal Hyphae
  18. 18.    Some examples of plant diseases caused by fungi: brown rot of cherries, peaches and apricots; apple scab. powdery mildew of roses, apples and other plants.
  19. 19. Brown rot powdery mildew (Monilinia fructicola) (Triticum sp.)
  20. 20. 2) Bacteria About 200 pathogenic species  Can be seen with a light microscope  Simple, unicellular  Reproduce by binary fission 
  21. 21.    Some of the commonly encountered bacterial diseases are: crown gall of rose, grape, apple, cherry and other ornamental plants fire blight of apple and pear
  22. 22. Crown Gall Fire Blight (Agrobacterium tumefaciens ) (Erminia amylovora)
  23. 23. 3) Viruses     Can only be seen using an electron microscope Extremely simplenucleic acid with a protein coat. Reproduce by taking over host reproductive machinery Often associated with insect vectors.
  24. 24.   Viruses can multiply only in a living host cell and can often spread systemically throughout the infected plant. Viruses may be transmitted from infected to healthy plants mechanically, through grafts, or contaminated propagating material; however, the most important means of spread is by insect transmission.
  25. 25. Viruses cause mainly two types of symptoms: mosaics and leaf curls.  Some examples:    rose mosaic potato leaf roll
  26. 26. Rose mosaic (Rose Mosaic Virus) (RMV) Potato leaf roll (Polerovirus)
  27. 27. 4) Nematodes Parasite worms  Very complex compared to other pathogens  Usually seen only with a light microscope  Reproduce by eggs. 
  28. 28.     Most of the nematodes feed on the underground parts of the plants (roots, tubers, bulbs, etc.) causing lesions or root knots. Some examples: Root knot nematodes on tomato, potato, beans and many other plants. Stubby root nematode of corn, onion.
  29. 29. Root knot nematodes (Meloidogyne) Stubby root nematode (Trichodoridae)
  30. 30. 5) Phytoplasmas      A prokaryotic organism that lacks a cell wall and survive in the phloem of plant The helical phytoplasmas are known as spiroplasmas. Round or elongate Usually seen only with an electron microscope Reproduce by binary fission
  31. 31.   Some of the commonly encountered phytoplasmas diseases: aster yellows phytoplasma on carrots, tomatoes, onions and lettuce.
  32. 32. Aster yellows phytoplasma
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×