Diseases of fruit plantation medicinal and aromatic crops (2+1)

Powdery mildew

Causal organism: Oidium piperis (Uppal, Kamat and Patel)
Symptoms

• Early leaf infection symptoms consist of the formation of circular light greyish white powdery patches or spots which gradually enlarge and turn powdery mass of fungal growth. Under ideal conditions both the leaf surfaces get covered by the white floury mass of fungal growth.
• It is followed by yellowing of the leaves which become brittle resulting in early leaf falls.
• The growing shoots are also affected in severe cases and whole crop may be destroyed. Photosynthesis process is reduced and yield reduction occurs.


Management

• Application of wettable sulphur (0.3%) is effective in controlling the disease.
  
• The control of powdery mildew is also achieved by spraying with Bordeaux mixture (0.5%) and also by the application of 0.5% suspension of colloidal sulphur.
• Spraying with Arsenium album @2000 potency has also been recommended to control the Colletotricum leaf spot diseases of piper beetle.