Yellow Leaf Disease of Arecanut

In news 

Recently, Yellow leaf disease of areca nut lead to a sharp decline in crop yield

About Yellow leaf disease of areca nut in India

Origin 

• Yellow leaf disease of arecanut (Areca catechu Linnaeus), known as ‘Kattuveezhcha’, ‘Chovakedu’ etc, in Malayalam and ‘Chandiroga’ in Kannada, was reported from Moovattupuzha. Meenachil and Chalakudi areas of Kerala in 1949.
• It was observed that the disease had some similarities with the ‘root and leaf disease’ of coconut prevalent in those areas.
• The disease, which affects the areca palms of all age groups, declines the plant’s productivity
• Vector: Planthopper (Proutista moesta)

Symptoms 

• The symptoms of the disease are the yellowing of leaves and the shedding of both mature and immature fruits. 
• The yellowing starts from the tips of the leaflets of the outer leaves gradually extending to the middle of the laminae
• The affected leaves often develop necrosis from their tips. 
• The diseased leaves possess smaller epidermal cells, stomatal pores and midrib parenchyma cells.
• Tips of the chlorotic leaves dry up. In the advanced stage all the leaves become yellow.
• Finally, the crown leaves fall off leaving a bare trunk. Root tips turn black and gradually rot

Other diseases of Arecanut

Arecanut Footrot : 

• The leaf lets in outer whorls become yellow and spreads to the whole leaf and the leaves droop down covering the stem.
• Later, the inner whorl leaves also become yellow. Subsequently all the leaves droop, dry up and fall off, leaving the stem alone.
• When infected trunk is cut open brown discoloration can be seen up to one metre from ground level.

Arecanut Mahali/Fruit rot: 

• Characteristic symptom is rotting and extensive shedding of the immature nuts which lie scattered near the base of the tree. 
• When infection occurs later in the season, it leads to rotting and drying up of nuts without shedding (known as ‘Dry Mahali’).

Arecanut  Bud rot:

• Initial symptom is the characteristic change of spindle leaf colour from green to yellow & then brownish.
• The leaves rot and the growing bud rots causing death of the palm.
• The affected young leaf whorl can be easily pulled off.
• The outer leaves also become yellow and droop down one by one leaving a bare stem.

Inflorescence die back of Arecanut  and button shedding: 

• The disease appears on the rachillae of the male flowers and then in the main rachis as brownish patches which soon spreads from tip downwards covering the entire rachis causing wilting. 
• The female flowers of the infected rachis shed and the whole inflorescence shows ‘die back’ symptom