Centre : YSPUHF,RC Kullu
Name of the Protocol
Development of protocol/ new method for isolation of Phytophthora cactorum causing collar rot of apple from soil
Nature : Modification of existing protocol
Crop / Pathogen : Apple / Phytophthora cactorum
The isolation of P. cactorum causing collar rot of apple carried by modified SADAMCAP method given by Horner and Wilcox (1995) by using sun hemp seeds as bait. Soil was collected upto 10 cm depth, sieved by passing through 2-2.5 mm sieves. Then air dried at room temperature for 2-4 days. 10 g of soil in Petri plant was moistened with 3.8ml of pond water and then incubated at 22± 1oC for 96 hrs. The plate was flooded by adding 12.5 ml pond water. These covered plates were then chilled at 6-8oC for 2hrs in the refrigerator. Then pre-soaked (6hrs)and surface sterilized sun hemp seeds(5-6No.)were put in the plate as bait and then incubated in light at 22± 1oC. After 4-5 days the germinating radicles with brown lesions near the tip were cut in small pieces, surface sterilized and transferred onto Petri plates containing specific CMA PARP medium and incubated at 22± 1oC. The fungal growth of P. cactorum was observed after 48-72 hrs.Two other baits viz., deodar needle and apple seeds were the next best in order.