ANALYSIS AND DISTRIBUTION OF TOMATO ROOT ROT IN ROCKWOOL
The nature of the mineral fibre matrix and the root colonisation pattern make root isolation and analysis more difficult than from soil or other substrates. Tomato cv. Marathon, inoculated with Phytophthora cryptogea, was grown to fruiting in rockwool slabs. A three-dimensional distribution of roots and Phytophthora was obtained by maceration-dilution plate counting, by microdissection and by separation of roots by dissolution of the rockwool fibre and binder. Most parts of the growing block and slab were colonised seven days after inoculation. The greatest root biomass and infection was found in and immediately beneath the growing block.
The results were discussed in relation to pre-disposition to infection and subsequent disease development.