Soil Solarization, Non-Host Crops, Bio-fumigation and Oil Cakes in Management of Collar Rot and White Root Rot Diseases in Apple

Soil solarization, twelve non-host crops, six bio-fumigation (mulching whole plant) and five oil cakes were evaluated against two important soil borne diseases viz., collar rot (Phytophthora cactorum (Leb. & Cohn) Schroeter) and root rot (Dematophora necatrix Hartig) of apple under pot and field condition in nursery (sick soil) during 20052010. Soil solarization of sick plots by using transparent polythene sheet (25μm) for 60 days provided 91.6 and 87.4 PDC of collar rot and white root rot, respectively. Growing of non-host crops viz., mustard (61.4%) and cabbage (56.4%) was highly effective against collar rot and root rot, respectively under pot conditions. Similarly, bio-fumigation separately with mustard and cabbage plants under pot conditions were correspondingly quite effective in controlling collar rot (80.2%) and root rot (64.1%) diseases. Evaluation of above non-host and biofumigation crops under nursery conditions (sick soil) revealed similar results but with slightly decreased disease control. Amongst oil cakes, addition of mustard cake both under pot and nursery conditions was highly effective (75.5, 72.4%) in controlling collar rot whereas; neem cakes provided maximum control (75.3%, 70.2%) of root rot pathogen. Combined treatment of soil solarization (60 days) separately with mustard cake and neem cake was quite effective against collar rot (98.2%) and root rot diseases (99.6%) in order.