Abstract

The effect of type of shading (coconut leaf thatch - CLT and coir mat - CM), seed rate (2. 89 and 7. 0 g/m2) and quantity of water provided (11 and 14 litres/m2 per day) on microclimatic conditions and consequent incidence and severity of seedling diseases of E. grandis was studied in an area of Kerala where high disease pressure of Cylindrocladium quinqueseptatum [Calonectria quinqueseptata] had been recorded. The type of shading provided over the seed beds appeared to be the most important factor. Shading with CLT led to low light intensity (av. 1463 lux) with high soil water potential, low soil and ambient temp., high severity of damping off caused by Pythium sp., Rhizoctonia solani and C. quinqueseptata and web blight (R. solani) and a poor seedling shoot: root ratio. Seed beds under CM shading had dispersed light (av. 22 299 lux), high severity of seedling blight (C. quinqueseptata) and shoot wilt (Sclerotium [Corticium] rolfsii) and a good seedling shoot: root ratio. Under