Studies on powdery mildew disease of mulberry (Morus alba): a new report from Uttar Pradesh, India

Abstract

During a survey of fruit trees in the months of November 2004 to January 2005, constant occurrence of powdery mildew disease of mulberry caused by Phyllactinia guttata was observed in and adjoining areas of Aligarh District of Uttar Pradesh. The symptom of powdery mildew disease of mulberry first appeared in the month of November in the form of small patches of white coloured powdery masses on the abaxial surface of mulberry leaves with corresponding lesions on the opposite surface (adaxial). When the disease progressed, these powdery patches grew in size and finally coalesced to cover the entire abaxial surface of leaves. These white powdery patches finally turn brown to black and leaves become yellow in colour. The development of cleistothecia was observed at the end of January, when conidial production slows down and eventually ceased. Cleistothecia were white at first, then turned orange to reddish brown and finally black when matured. Cleistothecia were usually hypophyllous, scattered, sometimes gregarious and large globose. The asci were numerous, 4–18 per cleistothecium and each ascus had two ascospores. Abnormal developments of cleistotheica were also observed. This is the first report of P. guttata on mulberry plants from Uttar Pradesh.

Keywords:

• Morus alba
• Phyllactinia guttata
• Cleistothecia