In this article we will discuss about the life cycle of plasmodiophora brassicae with the help of suitable diagrams. Cook and Swartz (1930) showed that the life cycle of P. brassicae comprises two distinct phases, the haplophase (primary phase) and the diplophase (secondary phase). The former occurs in the root hairs and the latter in the cells of the main [...]
The following points highlight the top five evolutionary trends on Oomycetes. 1. There is progressive evolution from the aquatic to land habitat. Members of orders Lagenidiales, Saprolegniales and Leptomitales are chiefly aquatic. The advanced order Peronosporales includes aquatic, amphibious and terrestrial forms. 2. The representatives of this class show a whole range from saprophytes (Saprolegnia) to facultative parasites (Pythium) and [...]
In this article we will discuss about:- 1. Occurrence of Pythium 2. Predisposing Factors of Pythium Debaryanum 3. Mode of Infection 4. Symptoms 5. Economic Importance 6. Salient Features. Occurrence of Pythium: P. debaryanum is the classic example of the most common species of Pythium which causes the widespread "damping off" disease of tobacco, tomato, mustard, chillies and cress seedlings. [...]