Occurrence of Powdery Mildew Disease of Tectona grandis (L.f.) at Aligarh District: A New Report from Uttar Pradesh

The symptoms of powdery mildew disease of teak appeared in the month of January in the form of characteristic small patches of white coloured powdery masses on the upper surface (adaxial) of teak leaves with corresponding chlorotic lesions on the lower surface (abaxial). As the disease progressed, these powdery patches grew in size and finally coalesced to cover the entire adaxial surface of leaves. Finally, white powdery patches turned brown to black and leaves turned yellow in colour due to necrosis. The development of cleistothecia was observed in the second week of March, when conidial production slowed down and eventually ceased. Young cleistothecia began to make their appearance on white powdery mildew mycelium on teak leaves. Asci numerous, 6–15 per cleistothecium, each ascus having 6–8 ascospores. Appendages were numerous, apex closely circinate or subhelicoid and not enlarged. The frequency of occurrence of powdery mildew disease on teak plants was 60.5% in and around AMU Campus, showed severe infection of Uncinula tectonae on teak.