1. Hull, R., Plant Path., 2, 39; 3, 130; 4, 134; 5, 130; 6, 131; 7, 131; 8, 145; 9, 151; 10, 149 (1953–61).
2. Russell, G. E., Ann. App. Biol., 46, 393 (1958).
3. Russell, G. E., Brit. Sugar Beet Rev., 28, 163 (1960).
4. De Clercq, S. W., Landbouwk. Tijdschr.'s Grav., 45, 143 (1933).
5. Roland, G., Rev. Path. Veg., 23, 185 (1936).