Publications for:

pest = Pythium (genus)
crop = Amaranthus (crop)

found 2 publications:

2007

First report of stem canker affecting Amaranthus caudatus in Argentina
Australasian Plant Disease Notes (2007) 2 (1), p. 5
publishers website - pestinfo wiki

1993

Diseases of Amaranthus spp. caused by Pythium aphanidermatum and Macrophomina phaseolina
Canadian Journal of Botany - Revue Canadienne de Botanique (1993) 71 (9), 1219-1223
publishers website - pestinfo wiki