COMMON DISEASE OF MAJOR CROP

Plant disease are a significant yield and quality constraint for growers of broadcare crops. Plant pathogen can be fungal, bacteria, virus and nematodes and can damages plant parts above or below the ground. Below are the example of disease of oil palm, rubber, paddy and cocoa:   

Disease in Oil Palm Crop:

  1.  BASAL STEM ROOT

  

 Casual Agent / Pathogen: Ganoderma boninense

Symptom & Damage:

• Rotten and destruction of basal stem tissues 
• New developing shoots will not expand  
• Leaves and fronds become wilt

Control:   

• Field sanitation
• Trunk injection    
• Fumigation
• Biological control                       

2.     UPPER STEM ROOT 

 

Casual Agent / Pathogen: Phelinnus noxious
 
Symptom & Damage:

• Lower leaves first become yellow and die from tip to the base
• This condition progresses to the middle of the crown and finally affected the spear leaves
• Dark brown to black crust of mycelium around infected stem

Control:

• Removed the infected part/plant
• Trunk injection using pressure injection apparatus
• Development of resistance varieties 

Disease In Rubber: 

 

1.          Pink Disease

Casual Agent:

                          Corticium salmonicolor

Symptoms & Damage:

• Affecting mainly the young rubber
• Rooting, drying up and cracking of the affected bark
• The leaves turn yellow and dry up

Control Methods:

• Two rounds of spraying with 1% Bordeaux mixture on the forks and branches
• Mature plants: Thiram 0.75% thiride with tridemorph 2%  

2.          Powdery Mildew

  Casual Agent: Oidium hevea

 Symptoms & Damage:

• Infected leaves get covered with white powdery masses
• Leaves shrive, curl and edges roll inwards
• Leaves fall and followed by twigs 

 Control Method:

• Sulphur mixed with Talc with ratio 70:30
• Bavistin 0.05%
• Most efficient:
  Alternate use of Bavistin and Sulphur is recommended to avoid resistance problem
  
  
   Disease In Paddy Crop
  1.       Rice Blast Disease
  
  
   

 Casual Agent:

-                                                  Pyricularia Oryzae

  Symptoms:

• Initial symptoms white to gray-green lesions or spots with darker borders produced on all parts of shoot
• Older lesions: white to gray with necrotic boarder

Control Methods:

• Used seed from a disease-free crop
• Destruction of alternate wild host
• Use of tolerant varieties

2.   False Smut

Casual Agent:

-                                                  Ustilaginoidea virens

Symptoms:

• The false smut fungus transform individual grains of the panicle into greenish spore balls with a velvety appearance
• Later, the ball become orange or yellowish green

Control methods:

•  Use certified seed
• Collect and destroy grains check secondary spread of disease helps in reducing inoculum for the next year
• Spray Carbendazim 

Disease In Cocoa: 

1. Black Pod Disease 

 

Casual Agent:

-                                                 Phytophthora palmivora

Symptoms:

• The disease begins with circular brown lesion that enlarges to cover the whole pod
• The cocoa pod become black and rotting
• Die-back 

Control Methods:

• Harvest pods regularly and remove disease pods
• Thin canopy to improve airflow and reduce humidity
• Space plating in well drained sites 

References:

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=2ahUKEwjU_YyUx87eAhULAXIKHUfYB2MQjhx6BAgBEAM&url=https%3A%2F%2Fwww.flickr.com%2Fphotos%2Fiita-media-library%2F4729834020&psig=AOvVaw3nFYoKD6ULVyNiY46eR7vI&ust=1542101837584721

https://www.agric.wa.gov.au/pests-weeds-diseases/diseases/crop-diseases

Prepared by: Nur Fasihah Binti Sharifful Bahri (2018224462)

Group: 2 (Plant pathology: Disease in major crop)