National Seed Health System
Sb 2.2 Phomopsis-Diaporthe – Blotter
|PATHOGEN: Phomopsis/Diaporthe complex|
|HOST: Soybean (Glycine max)|
|COMMON NAME: pod and stem blight; seed decay; stem canker|
|METHOD: Sb 2.2 Blotter (McGee and Nyvall, 1984) (formerly Sf 2.2)|
|METHOD CLASS: STANDARD (A)|
|SAMPLE: 400 seeds|
1. Two sterilized blotters are placed in plastic boxes.
2. Moisten blotters with 80ml of sterile water, containing 40mg of 2,6 dichloro-6-nitroaniline (Botran 75W).
3. Four sets of 100 seeds are surface sterilized in 1% NaOCl for 30 seconds and then rinsed in sterile water.
4. Seeds are incubated at 25°C for 10 days under continuous light.
5. Seeds are evaluated for the presence of fungi in the Phomopsis/Diaporthe complex characteristic dense, white fungal growth.
McGee, D. C., Brandt, C. L. and Burris, J. S. 1980. Seed mycoflora of soybeans relative to fungal interactions, seedling emergence, and carry-over of pathogens to subsequent crops. Phytopathology. 70(7):615-617.
McGee, D. C. and Nyvall, R. F. 1984. Soybean seed health. Coop. Ext. Serv. Iowa State Univ. Pm- 990.